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Succession Ecology of Coptotermes formosanus Shiraki Following Area-Wide Colony Elimination.

Permanent Link: http://ufdc.ufl.edu/UFE0025089/00001

Material Information

Title: Succession Ecology of Coptotermes formosanus Shiraki Following Area-Wide Colony Elimination.
Physical Description: 1 online resource (57 p.)
Language: english
Creator: Mullins, Aaron
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: Entomology and Nematology -- Dissertations, Academic -- UF
Genre: Entomology and Nematology thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: SUCCESSION ECOLOGY OF COPTOTERMES FORMOSANUS SHIRAKI FOLLOWING AREA-WIDE COLONY ELIMINATION The succession and population recovery of Coptotermes formosanus Shiraki colonies was monitored following an area-wide elimination of all detectable colonies in Louis Armstrong Park, New Orleans, LA. From September 2003 to August 2005 six colonies reinvaded the vacant niche created by the full elimination. These colonies expanded their territories throughout the study period. This represented 43% of the original number of colonies present in the Park before the elimination. In order to determine the mode of the reinvasion, alate populations and nuptial pair establishment was monitored during the C. formosanus dispersal flight seasons. Alate populations were found to decrease following the area-wide elimination, and nuptial pairs were discovered up to one year following the elimination. Morphological data were collected from field colonies before the full elimination in 2002 and again in 2005 following the re-invasion of these territories by new colonies. These data was used in order to estimate the age of reinvading colonies compared to their predecessors. It is proposed that the first three reinvading colonies detected were older, established colonies which were undetectable before the full elimination, or were colonies present outside of the Park, which expanded their foraging territories into the Park in the absence of intraspecific, intercolonial competition from the eliminated populations. The subsequent three colonies to reinvade appeared to be small colonies founded during or just before the study period by an imago pair following a dispersal flight into the park from outlying areas. The implications of this study on subterranean termite area-wide integrated pest management strategies are discussed.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Aaron Mullins.
Thesis: Thesis (M.S.)--University of Florida, 2009.
Local: Adviser: Su, Nan-Yao.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0025089:00001

Permanent Link: http://ufdc.ufl.edu/UFE0025089/00001

Material Information

Title: Succession Ecology of Coptotermes formosanus Shiraki Following Area-Wide Colony Elimination.
Physical Description: 1 online resource (57 p.)
Language: english
Creator: Mullins, Aaron
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: Entomology and Nematology -- Dissertations, Academic -- UF
Genre: Entomology and Nematology thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: SUCCESSION ECOLOGY OF COPTOTERMES FORMOSANUS SHIRAKI FOLLOWING AREA-WIDE COLONY ELIMINATION The succession and population recovery of Coptotermes formosanus Shiraki colonies was monitored following an area-wide elimination of all detectable colonies in Louis Armstrong Park, New Orleans, LA. From September 2003 to August 2005 six colonies reinvaded the vacant niche created by the full elimination. These colonies expanded their territories throughout the study period. This represented 43% of the original number of colonies present in the Park before the elimination. In order to determine the mode of the reinvasion, alate populations and nuptial pair establishment was monitored during the C. formosanus dispersal flight seasons. Alate populations were found to decrease following the area-wide elimination, and nuptial pairs were discovered up to one year following the elimination. Morphological data were collected from field colonies before the full elimination in 2002 and again in 2005 following the re-invasion of these territories by new colonies. These data was used in order to estimate the age of reinvading colonies compared to their predecessors. It is proposed that the first three reinvading colonies detected were older, established colonies which were undetectable before the full elimination, or were colonies present outside of the Park, which expanded their foraging territories into the Park in the absence of intraspecific, intercolonial competition from the eliminated populations. The subsequent three colonies to reinvade appeared to be small colonies founded during or just before the study period by an imago pair following a dispersal flight into the park from outlying areas. The implications of this study on subterranean termite area-wide integrated pest management strategies are discussed.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Aaron Mullins.
Thesis: Thesis (M.S.)--University of Florida, 2009.
Local: Adviser: Su, Nan-Yao.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0025089:00001


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1 SUCCESSION ECOLOGY OF COPTOTERMES FORMOSANUS SHIRAKI FOLLOWING AREA-WIDE COLONY ELIMINATION By AARON JAMES MULLINS A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2009

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2 2009 Aaron Mullins

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3 To Mom and Dad

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4 ACKNOWLEDGMENTS I would like to begin by thanking foremost my advisor, Nan-Yao Su for his patience, encouragement and direction over the last few years. My Committee, Rudolph Scheffrahn and William Kern provided much needed insight into this document. A somber thanks is in order to Claudia Reigel, Ed Freytag and Kenneth Brown with the New Orleans Mosquito and Termite Control Board. They provided me with support, encouragement, patience and friendship in difficult times. In addition, they provided me with critical guidance over the years and initial reviews of this document. Thanks to Mike Carroll a nd Ed Bordes for making the New Orleans Mosquito and Termite Control Board what it is, and showing me how administration can work. The rest of the crew at the New Orleans Mosquito and Termite Control Board; Perry Ponsetti, Barry Yokum, Barry Lyons and Carr ie Owens provided me with much needed support, laughs and physical labor over the years. Finally I would like to thank Matt Messenger, my mentor and personal friend who taught me about much more than termites. I could not have finished this work without th e support of my parents, Donald and June Mullins. Who provided understanding, support and encouragement when times were tough.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ...............................................................................................................4 LIST OF TABLES ...........................................................................................................................7 LIST OF FIGURES .........................................................................................................................8 ABSTRACT ...................................................................................................................................10 CHAPTER 1 INTRODUCTION ..................................................................................................................12 Pest Status and Remedial Treatment Limitations ...................................................................12 Description and Life History ..................................................................................................13 Distribution, Accidental Introductions and Spread ................................................................14 The Problem in New Orleans .................................................................................................14 Implications of Baiting Technology .......................................................................................15 Area-Wide Approach to Termite Control ...............................................................................16 Armstrong Park as a Test Site for Reinvasion Studies ...........................................................16 2 REINVASION OF LOUIS ARMSTRONG PARK VIA ALATE DISPERSAL FLIGHTS ................................................................................................................................18 Introduction .............................................................................................................................18 Dispersal Flights of Coptotermes formosanus ................................................................18 Trapping alates as an indicator of C. formosanus populations ........................................18 Materials and Metho ds ...........................................................................................................19 Monitoring Alate Populations and Dispersal Flight Activity ..........................................19 Monitoring In-Ground Nuptial Pairs and Incipient Colonies ..........................................20 Monitoring Colony Dispersal Flight Ac tivity .................................................................21 Results .....................................................................................................................................22 Decline in Alate Activity Over Time ..............................................................................22 Presence of Established Nuptial Pairs .............................................................................23 Discussion ...............................................................................................................................26 Decrease in Dispersal Flight Activity ..............................................................................26 Intraspecific, Intercolonial Competition ..........................................................................27 3 EXPANSION OF TERRITORIES FOLLOWING AREA -WIDE COLONY ELIMINATION ......................................................................................................................30 Introduction .............................................................................................................................30 Previous Reinvasion Studies in Louis Armstrong Park ..................................................30 Area-Wide Full Elimination and Successive Reinvasion ................................................30 Materials and Methods ...........................................................................................................31

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6 Monitoring In-Ground Subterranean Termite Activity ...................................................31 Mark-Recapture and Colony Characterization ................................................................32 Results .....................................................................................................................................33 Reinvading Colony Locations .........................................................................................33 Reinvading Colony Foraging Territory Expansion .........................................................34 Discussion ...............................................................................................................................36 Time Frame of Reinvasion ..............................................................................................36 Undetected Colonies and Incipient Colonies ..................................................................37 Factors for Reinvasion .....................................................................................................37 4 MORPHOMETRIC CHARACTERIZATION OF REINVADING COLONIES FOLLOWING AREA-WIDE COLONY ELIMINATION ....................................................39 Introduction .............................................................................................................................39 Reinva sion of Vacant Territories Following Area -Wide Colony Elimination ...............39 Morphometry and Colony Characterization ....................................................................39 Materials and Methods ...........................................................................................................40 Morphology Measurements .............................................................................................40 Morphology Data analysis ...............................................................................................42 Results .....................................................................................................................................42 Original Colonies Versus Reinvading Colonies ..............................................................42 Discussion ...............................................................................................................................44 Relativ e Age of Reinvading Colonies .............................................................................44 5 CONCLUSIONS ....................................................................................................................47 LIST OF REFERENCES ...............................................................................................................51 BIOGRAPHICAL SKETCH .........................................................................................................56

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7 LIST OF TABLES Table page 4-1 Statistical analysis of morphological characteristics of original C. formosanus colony F8 vs. reinvading colony R2 in overlapping area 1 of Armstrong Park. ...........................43 4-2 Statistical analysis of morphol ogical characteristics of original C. formosanus colony F8 vs. reinvading colony R6 in overlapping area 2 of Armstrong Park. ...........................43 4-3 Statistical analysis of morphological characteristics of original C. formosanus colony F2 vs. reinvading colony R3 in overlapping area 2 of Armstrong Park. ...........................43

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8 LIST OF FIGURES Figure page 2-1 Locations of 68 glue board traps and one New Jersey-style light trap in Louis Armstrong Park..................................................................................................................20 2-2 Location of all Sentricon in-ground stations in Louis Armstrong Park...........................21 2-3 Total annual C. formosanus alate catch from 62 glue-board traps and 1 New Jersey style light trap in Louis Armstrong Park............................................................................22 2-4 C. formosanus nuptial pairs (labeled C.f.n-1 to C.f.n-4) found in Sentricon! inground stations in Louis Armstrong Park from June to December, 2003........................23 2-5 C. formosanus and R. flavipes nuptial pairs (labeled C.f.n-5 and R.f.n-1) found in Sentricon! in-ground stations in Louis Armstrong Park from March to June 2004..........24 2-6 An example of a nuptial pairing in a Sentricon in-ground monitoring station in Louis Armstrong Park........................................................................................................25 2-7 An incipient colony of C. formosanus including queen (a), king (b) and workers (c) found inside a Sentricon monitoring device (d) in Louis Armstrong Park.....................26 3-1 The Sentricon Colony Elimination System was used for monitoring subterranean termite activity in Armstrong Park....................................................................................32 3-2 New C. formosanus colonies detected in Louis Armstrong Park from September 2003 to March, 2005..........................................................................................................34 3-3 Comparison of the number of Sentricon monitoring stations with C. formosanus activity over time in Louis Armstrong Park, New Orleans, LA........................................35 3-4 An example showing expansion of a reinvading C. formosanus colony into new foraging territory from September 2003 to March 2005 in Louis Armstrong Park, New Orleans, LA................................. ..............................................................................36 3-5 A typical population logistic growth curve showing the hypothetical population of C. formosanus in Armstrong Park..........................................................................................38 4-1 Two aerial maps Of Louis Armstrong Park showing C. formosanus colonial territories of the original 14 colonies eliminated in 2002-2003 (a), and the reinvading colonies present in the summer of 2005 (b).......................................................................41 4-2 Eliminated and reinvading C. formosanus colonies in Louis Armstrong Park, showing three areas with colonial foraging territory overlap or near-overlap...................41

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9 4-3 A box plot of individual worker wet mass from all of the original colonies (20 workers per colony, pooled data) in Armstrong Park (F0), compared to the reinvading colonies R1 through R6. ..................................................................................44

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10 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science SUCCESSION ECOLOGY OF COPTOTERMES FORMOSANUS SHIRAKI FOLLOWING AREA-WIDE COLONY ELIMINATION By Aaron James Mullins August 2009 Chair: Nan-Yao Su Major: Entomology and Nematology The succession and population recovery of Coptotermes formosanus Shiraki colonies was monitored following an area -wide elimination of all detectable colonies in Louis Armstrong Park, New Orleans, LA. From September 2003 to August 2005 six colonies reinvaded the vacant niche created by the full elimination. These colonies expanded their territories throughout the study period. This represented 43% of the original number of colonies present in the Park before the elimination. In order to determine the mode of the reinvasion, alate populations and nuptial pair establishment was monitored during the C. formosanus dispersal flight seasons. Alate populations were found to decrease following the area -wide elimination, and nuptial pairs were discovered up to one year following the elimination. Morphological data were collected from field colonies before the full elimination in 2002 and again in 2005 following the re -invasion of these territories by new colonies. Th ese data was used in order to estimate the age of reinvading colonies compared to their predecessors. It is proposed that the first three reinvading colonies detected were older, established colonies which were undetectable before the full elimination, or were colonies present outside of the Park, which expanded their foraging territories into the Park in the absence of intraspecific, intercolonial competition from the eliminated populations. The

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11 subsequent three colonies to reinvade appeared to be small colonies founded during or just before the study period by an imago pair following a dispersal flight into the park from outlying areas. The implications of this study on subterranean termite area -wide integrated pest management strategies are discussed.

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12 CHAPTER 1 INTRODUCTION Pest Status and Remedial Treatment Limitations Coptotermes formosanus Shiraki is a highly studied termite species of great economic importance. It is generally accepted that this species originated in Southeastern China (Kitstner, 1985). However, due to its pestiferous nature and human -aided transport it now has a widespread distribution in subtropical and temperate regions around the world (Su, 2003). Of the roughly 3,000 known species of termite, only about 70 to 80 of them are considered pests of human structures and commodities. Half of those are occasional problem species, leaving only 4% of all Isoptera considered of serious economic importance (Edwards and Mill, 1985). Although the vast majority of isopteran taxa are innocuous to h uman developments, the genus Coptotermes is particularly pestiferous. Of the 30 known species, 17 (56%) are considered of high economic importance (Su, 2003a). In the United States alone, C. formosanus is believed to cause approximately $1 billion annually in property damage, repair costs and control measures (Suzkiw, 1998). There are many reasons why C. formosanus is a particularly problematic termite pest, notably colony size. Although wood consumption rates (mg wood/g termites/day) of individual worker termites of Reticulitermes sp and C. formosanus were approximately the same, the larger Coptotermes colony size results in more feeding at a foraging site, causing more significant and rapid damage (Su and Tamashiro, 1987). Coptotermes formosanus is also known to nest in and damage living plants as well as a wide variety of lignocellulosic materials. Many common shade, ornamental, and fruit trees are susceptible to attack and damage from these termites (Lai et al., 1983; Chambers, 1988; Messenger and Su, 2005). The damage caused to standing live trees can weaken them to the

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13 point of breakage (Osbrink, 1999). While Reticulitermes spp are known to attack living plants, it is an uncharacteristic behavior (Spink, 1967). Another contributing factor to th e C. formosanus problem is its resilience when treated with conventional soil barrier termiticides. Often a treatment that is sufficient for control of other species of subterranean termites is ineffective against C. formosanus (Beal and Smith, 1971; Spink, 1967). With the presence of condensation from air conditioning, and poor building drainage, C. formosanus is known to have enough available moisture to establish above -ground colonies with no soil contact. This presents another treatment concern when soi l barrier termiticides are used (La Fage, 1987). Description and Life History Foraging galleries of C. formosanus are made up of a complex series of underground, and occasionally, aboveground nests interconnected via tunnels. A single interconnected colon y can have a foraging territory range of 83 -1634m2 (Messenger and Su, 2005). The biology of C. formosanus follows the typical structure of eusociality as other termites in the family Rhinotermididae. Three distincts castes are present, reproductives, worke rs and soldiers. The reproductive caste, comprised of imago queens, kings and alates, secondary reproductives, and immature alates known as nymphs. Alates are approximately 12 -15 mm in length, are golden brown and along with Coptotermes gestroi (Wasmann) a re easily distinguished from other North American termites by their wings, which are not reticulated, and are covered by setae. The worker caste consists of determinate true workers, as opposed to indeterminate pseudergates. The worker caste makes up the majority of the colony, their role includes foraging for nutrients, nest building, grooming, and providing food for other castes. Soldiers of C. formosanus are easily distinguishable from Reticulitermes spp. by their abundance, making up about 10% of the colony, their oval or teardrop shaped head, and a large,

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14 forward facing fontanel, which ejects a milky -white defensive secretion when attacked. They also elicit more aggressive behavior than Reticulitermes spp (Spink, 1967). Distribution, Accidental Introductions and Spread Coptotermes formosanus currently has a global distribution in subtropical and temperate environments with a northern and southern boundary of approximately 35 from the equator (Su, 2003a). A major factor of the spread of C. formosanus from its native range is its capacity to infest ships and barges (Bess, 1970; Oshima, 1919). It has been introduced to new areas around the world in this manner through transport of infested lignocellulosic materials or via dispersal flights from infested ships into harbor sites. It was likely transported to Japan from China prior to the 16th century (Su, 2003a) and first discovered in Hawaii in 1907 (Swezey, 1914). The pacific theater during World War II was the likely cause of its introduction into port cities of the southern United States. It was discovered in Houston, Texas, New Orleans, Louisiana and Charleston, South Carolina in the 1960s (La Fage, 1987). Human -aided transport of infested railroad ties, pallets, utility poles and other lignocellulosi c products have resulted in numerous infestations throughout the southern United States. This species is now found in at least 10 states (Woodson et al., 2001). The Problem in New Orleans The City of New Orleans, Louisiana has had a particularly significa nt problem with C. formosanus. Of the estimated $1 billion annual cost of property damage, repairs and control measures for C. formosanus damage in the US, roughly $300 million is accrued in the city of New Orleans alone (Suzkiw, 1998). The large amount o f damage caused in New Orleans is the result of several factors. First is the subtropical and wet climate that has proven ideal for this species. Second, the age of the infestation in New Orleans provided more time for C. formosanus to become established t han

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15 other sites in the continental U.S. resulting in more time for colony development and thus a higher population. Third, old construction, particularly in the French Quarter often includes absorbent sandstone brick and stucco, which retains moisture. Fou rth, many buildings were constructed with flat roofs, where standing water can provide a source of moisture for aboveground nests. Both of these last two construction practices lead to moisture conditions conducive for the potential development and mainten ance of aboveground colonies, independent of soil contact. Such colonies are difficult to control, as they avoid contact with traditional soil barrier termiticide treatments. These construction practices were in place long before consideration of methods t o counter the success of C. formosanus was needed. The common use of shared-wall construction further complicates remedial treatment because of difficulty in application of traditional liquid termiticide barrier treatments (La Fage, 1987). Implications of Baiting Technology Soil termiticide barriers, while protecting a structure from damage, usually do not impact the total population of subterranean termites in an area (Su and Scheffrahn, 1988). However, baiting technology has been shown to effectively red uce subterranean termite populations, by the elimination of colonies (Su et al., 1993; Su, 1994, 2005). The success of these approaches has created the possibility for, and implementation of, area -wide subterranean termite programs (Lax and Osbrink, 2003; Smith et al., 2006; Su et al., 2004). This approach was considered implausible before the development of these new technologies (Su, 2003), but now area -wide subterranean termite management may be particularly effective when considering the massive economi c impact the establishment of C. formosanus has had in the southeastern United States and historic New Orleans in particular, (Su and Scheffrahn, 1990).

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16 Area-Wide Approach to Termite Control In 1998, the U.S. Department of Agricultures Agricultural Resea rch Service (USDAARS) established the National Formosan Subterranean Termite Program, Operation Full -Stop. This program was the first of its kind to attempt area -wide control of C. formosanus in the French Quarter of New Orleans (Lax and Osbrink, 2003). With the implementation of area -wide management of any insect species, a key question must be asked: after the target species has been removed from an area, what is the time frame and mode o f reinvasion if the use of control measures are terminated? In the case of C. formosanus, reinvasion may be caused by colonies outside of the managed area expanding their range into vacated foraging territories, or by dispersal flights originating outside of the managed area, followed by coupling and subsequent colony es tablishment via male and female imagoes inside the vacated territories. Armstrong Park as a Test Site For Reinvasion Studies Louis Armstrong Park, bordering the French Quarter in New Orleans has been the site of extensive termite ecology studies since 199 8 (Messenger et al, 2005; Husseneder et al., 2005). The Park provides a unique opportunity to study the biology and ecology of an invasive species in an urban environment. It was chosen as a test site because of its close proximity to the French Quarter, and its relative lack of structures, which allows for easy access to termite colonies via in-ground monitoring stations and wooden stakes. A major component of studies in Armstrong Park has involved the selective elimination and subsequent reinvasion of for aging territories by bordering colonies of C. formosanus as well as Reticulitermes spp ., (Messenger et al., 2005). A full elimination of all detectable colonies in Armstrong Park was completed in 2003 using two insect growth regulator bait toxicants hexafl umuron and noviflumuron (M. Messenger,

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17 unpublished data). These treatments were terminated in order to study the reinvasion of Armstrong Park following area-wide termite control. The objectives of this study were: 1. To examine the mode of reinvasion via imag oes following dispersal flights from outside of the Park. 2. To document how quickly C. formosanus would reinvade the Park. 3. To determine whether the Park would be reinvaded by older, more established colonies moving in from foraging territories located adjac ent to the Park, or by smaller, incipient colonies founded by alate pairs that may have flown into the Park and are able to expand their range in the absence of intraspecific, intercolonial competition with established colonies within the study area.

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18 CHAPTER 2 REINVASION OF LOUIS ARMSTRONG PARK VIA A LATE DISPERSAL FLIGHTS Introduction Dispersal Flights of Coptotermes formosanus Dispersal flights are the primary means of mate selection and reproduction in the Isoptera. Unlike mobile, solitary insects, termi tes spend their entire lives within the confines of a colony. The winged reproductive caste functions as the primary means of reproduction and new colony foundation outside of the colonial territory. Alates fly away from the parental nest, shed their wings, and form tandem pairs with other de -alates. This tandem pair with the female in the lead then seeks a location to form a nuptial chamber, mate, and begin producing offspring in the form of workers and soldiers (Raina et al., 2003). Dispersal flights and the presence of alates is often the first indication a homeowner has of the presence of termites in a structure. In Louisiana, identification of the termite species present can often be determined simply by the date and time of day the dispersal flight tak es place (Messenger, 2002). The dispersal flights of C. formosanus in New Orleans, LA, occur during a two-month period from late April to late June. Dispersal flights occur in peaks throughout this season with marked decreases in activity for 5 to 9 days between peaks. The highest activity of dispersal flights occurs in mid -May (Henderson, 1996). Dispersal flights occur during dusk, alates emerge from their parental nests and fly about, aggregating around light sources. C. formosanus alates have been docu mented to have a maximum flight distance range of close to 1 Kilometer (Messenger and Mullins, 2005). Trapping alates as an indicator of C. formosanus populations Due to their tendency to fly toward, and aggregate about light sources, light traps are frequently used to determine the presence of C. formosanus in an area (Brown et al. 2007), as

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19 well as to monitor the overall population in an area over time (Su et al. 2004; Henderson, 1996, Lax and Osbrink, 2003). The presence of nuptial pairs in copulatoria h as also been used to monitor initiation of aerial colonies (Su et al. 1989). A total elimination of all detectable C. formosanus colonies in Louis Armstrong Park was conducted between July 2002 and June 2003 using the bait toxicants hexaflumuron and noviflumuron (M. Messenger, unpublished data). Dispersal flight activity was monitored in the Park as a means of observing the overall reinvasion of the Park by C. formosanus alates following this area -wide elimination. Materials and Methods Monitoring Alate Pop ulations and Dispersal Flight Activity Subterranean termite dispersal flight activity in Armstrong Park was monitored from 1999 to 2005 using 68 Trapper glue board traps (20.7 cm x 10.2 cm) (Bell Laboratories Inc., Madison, WI), and one New Jersey-style l ight trap Of the 68 glue board traps, 34 were installed on light posts in Congo Square located on the southeastern edge of the Park, 28 were suspended along the perimeter fence surrounding the Park, and six were suspended from a magnolia tree in the Northwestern edge of the Park. (Fig. 2.1). The New Jersey-style light trap was installed in approximately the center of the Park Traps were installed each April, before the start of the C. formosanus dispersal flight season and removed by mid -July when dispersal flight activity ended. Each trap was checked and replaced weekly or biweekly and the total number of C. formosanus and other termite alates were counted. Light traps were monitored by M. T. Messenger (USDA -ARS, unpublished data) from 1999 to 2002.

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20 Figure 2-1. Locations of 68 glue board traps and one New Jersey -style light trap in Louis Armstrong Park. Monitoring In-Ground Nuptial Pairs and Incipient Colonies Between the years 1999 and 2003, 816 Sentricon (Dow AgroSciences, Indianapolis, IN) in-ground stations and bucket style underground monitoring stations (UMS) (Su and Scheffrahn, 1986) were installed throughout Louis Armstrong Park (Messenger, 2004 ) (Fig 2.2). The Sentricon stations were monitored using the DowAgrosciences ESP termite detect ion system on a monthly or bi -monthly basis throughout the test period. The DowAgrosciences ESP termite detection system provides a wireless means of checking stations for termite activity. A

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21 Transensor device inside of the monitoring station transmits s tation activity to an electronic scanning device. All subterranean termite activity in the stations was recorded. This included the presence of de-alates and established nuptial pairs. Figure 2-2. Location of all Sentricon in-ground stations in Loui s Armstrong Park. Monitoring Colony Dispersal Flight Activity In addition to in -ground stations, trees, buildings and other structures were periodically inspected throughout the test period for signs of dispersal flight activity within the Park. Signs of

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22 flight activity included detection and documentation of the presence of nymphs and construction of dispersal flight tubes. Results Decline in Alate Activity Over Time The overall alate catch dropped following the area -wide elimination of all detectable i nground colonies of C. formosanus in Louis Armstrong Park in 2002 (Fig. 2.3). Figure 2-3. Total annual C. formosanus alate catch from 62 glue -board traps and 1 New Jersey style light trap in Louis Armstrong Park. Alates were captured each year during t he entire dispersal flight season lasting from April to July.

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23 Presence of Established Nuptial Pairs Over the year following the full elimination (June 2003 to June 2004), 5 separate nuptial pairings of C. formosanus and one nuptial pairing of R. flavipes were discovered in Sentricon! in-ground stations (Figs. 2.4 and 2.5). The first two nuptial pairings ( C.f. n-1 and n-2) were discovered in June 2003 in the northern area of the Park (Fig. 2.4). Figure 2-4. C. formosanus nuptial pairs (labeled C.f.n-1 to C.f.n-4) found in Sentricon! in-ground stations in Louis Armstrong Park from June to December, 2003.

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24 Figure 2-5. C. formosanus and R. flavipes nuptial pairs (labeled C.f.n-5 and R.f.n-1) found in Sentricon! in-ground stations in Louis Armstrong Park from March to June 2004. The pairing labeled C.f n-1 was a nuptial triad, consisting of one female and two male de alates (Fig. 2.6). The pairing labeled C.f n-2 had excavated a nuptial chamber in the station, however only a male de -alate was recovered. The nuptial pair labeled C.f n-3 was discovered in October 2003 and consisted of an entire incipient colony including one queen, one king, 30 workers and 2 soldiers (Fig. 2.7). All of the workers and soldiers had an extremely small body size. The queen was not visibly physogastric.

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25 The nuptial pair labeled C.f n-4 was discovered in December 2003 and was a simple pairing of one male and one female de -alate. Following the 2004 dispersal flight season, another nuptial pair labeled C.f.n-5 was discovered the following June. Though the one male and one female pair had excavated a nuptial chamber, the pair was dead and slightly decomposed upon discovery. In March 2004, an R. flavipes nuptial pair was discovered and labeled R.f.n-1 (Fig. 2.5). No established de -ala te pairs were discovered following June 2004. Neither dispersal flight tubes, nor pre -alate nymphs were discovered during the test period. Figure 2-6. An example of a nuptial pairing in a Sentricon in -ground monitoring station in Louis Armstrong Park. This nuptial triad was labeled C.f.n-1.

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26 Figure 2-7. An incipient colony of C. formosanus including queen (a), king (b) and workers (c) found inside a Sentricon monitoring device (d) in Louis Armstrong Park. This nuptial pair with offspring was labell ed C.f.n-3. Discussion Decrease in Dispersal Flight Activity Though a predictable drop in alate trap recovery was observed following the area -wide elimination of detectable colonies, a steady decrease in alate recovery was also observed the previous three years Fig, 2.3, (M. Messenger, unpublished data). A logical explanation for this decline is that the decrease in total alate recovery coincides with a large -scale area -wide

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27 subterranean termite control program in the French Quarter, adjacent to the Park (Lax and Osbrink, 2003). After all detectable colonies were eliminated in Armstrong Park, C. formosanus alates continued to be recovered in the Park, both during dispersal flights, as well as following de-alation, mating and establishment of a nuptial cha mber. No evidence of dispersal flight activity was observed in the Park (in the form of dispersal flight tubes) during the test period. This appeared to suggest that the continued alate recovery was due to alates flying into the Park from outlying areas (Messenger and Mullins, 2005). Intraspecific, Intercolonial Competition In 2002-2003 all large, detectable colonies of C. formosanus were eliminated. The colonies were considered eliminated when all feeding and presence of the colony had ceased for 2 months (M. Messenger, unpublished data). As a result of the full elimination, Armstrong Park represented a vacant niche, devoid of large, established subterranean termite territories amid a city infested with C. formosanus. Establishment of new colonies into the Park via alate pairs was observed in the form of discovery of nuptial chambers, mated pairs of imagoes, as well as the recovery of an entire incipient colony. This re -invasion of the Park from outside sources was a predictable result of area -wide colo ny elimination, since C. formosanus is well established in the French Quarter and surrounding areas, reinvasion pressure from these adjacent areas is an obvious source of these new introductions. However, nuptial pairs were only discovered for 1 year following the area -wide colony elimination. Most of these were discovered within 5 months following the first dispersal flight into a vacant Armstrong Park. Neither nuptial pairings, nor excavated nuptial chambers were discovered after the first year of area -wide colony elimination, nor had they been observed before the elimination (M.Messenger, personal communication). This suggests a window of opportunity of 1 year for alate pairs to establish new colonies detectable by our method in a newly vacated niche fo llowing area -wide colony elimination. Such

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28 a phenomenon could be explained by an increasing intraspecific, intercolonial competition with other colonies competing for the same resources. Chapter 3 and 4 of this thesis discuss six colonies that became estab lished following the area -wide invasion. These colonies were not discovered as nuptial pairs or incipient colonies, rather as established colonies outside of the Park foraging into new areas and encountering the monitoring devices as a result of that terri torial expansion. Intraspecific, intercolonial competition for territory and resources is well documented in the ants (Gordon, 1991; Hlldobler and Lumsden, 1980). In studies with the red harvester ant Pogonomyrmex barbatus Molefacieus, it was found that young colonies nearing reproductive maturity are more likely to engage in conflict with conspecific neighbors. Very young colonies with limited individuals, and older colonies with large, established foraging territories are more likely to avoid intraspecif ic conflict (Gordon, 1991). This can be explained by means of economics. Very young colonies have few individuals, and any gains to be had (through territorial expansion) are minimized because potential loss of individuals is a high price to pay. On the other hand, old colonies with large, established foraging territories may have access to an unusable surplus of resources within their territory so fighting for new territory may not be worth the expense of losing individual colony members. Moderately young colonies, however, would presumably have a greater need to expand territory because of the rising need for resources, and as a result the cost/benefit ratio of engaging in intercolonial aggression becomes less (Hlldobler and Lumsden, 1980). Intercolonial aggression behavior in harvester ants is easily observable because foraging trails are out in the open, foraging territories occur in two dimensions, and conspecific encounters with neighboring colonies are visible. In subterranean termites, however, such

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29 encounters would be virtually undetectable because of cryptic foraging underground. Intraspecific, intercolonial behavior in the laboratory has been observed in this species (Shelton and Grace, 1997; Messenger and Su, 2005b). An increasing number and rang e of young, competing colonies in Armstrong Park may result in the short period of time (!1yr.) new colonies have to become established via alate pairs into this newly vacated niche.

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30 CHAPTER 3 EXPANSION OF TERRITO RIES FOLLOWING AREA-WIDE COLONY ELIMINATION Introduction Previous Reinvasion Studies in Louis Armstrong Park Results from field studies have indicated that neighboring colonies will readily reinvaded vacant foraging territories of eliminated colonies (Messenger et al., 2005). Because simultaneo us eradication of all subterranean termites from a given area is unlikely, it is important to explore and consider potential reinvasion scenarios following area -wide approaches to subterranean termite control (Su, 2003). Area-Wide Full Elimination and Successive Reinvasion Louis Armstrong Park was selected as a test site to study the reinvasion of C. formosanus following area-wide colony elimination. Baiting of all previously detected and characterized colonies (Messenger and Su, 2005a) with noviflumuron or hexaflumuron bait toxicants began in July 2002, and was terminated in September 2003 (Messenger et al. unpublished data). A colony was considered eliminated when bait consumption dropped to zero, and no termites were observed foraging in the previously oc cupied station for at least two months. Any newly detected termite activity after the full elimination was not baited, in order to monitor the reinvasion. Monitoring of termite activity continued through March 2005 in order to document the successive reinv asion of C. formosanus in the Park. Dispersal flight activity into the Park is discussed in Chapter 2 of this thesis. Territory expansion of incipient and previously undetected established colonies is addressed here and in Chapter 4.

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31 Materials and Methods Monitoring In-Ground Subterranean Termite Activity Eight hundred and sixteen in -ground stations were monitored monthly for subterranean termite activity from September 2003 through August 2005 using the DowAgrosciences ESP termite detection system (Fig. 3.1). When termite activity was discovered, a sample of approximately 50 individual foragers (workers and soldiers) was collected and placed in a 13 ml vial (VWR, West Chester, PA) containing 100% ethanol for future genetic profiling. Consumption of the monitoring wood was visually estimated and recorded, as was an estimate of the number of foragers present. The monitoring device was then replaced and the termites were returned to the station. In order to facilitate termite collection for mark -recapture, at least one of the active stations in a localized area was replaced with a UMS. A strip of corrugated cardboard 15cm by 1.5m (Uline, Wakegan, IL) was rolled, moistened, and placed in the UMS to facilitate termite collection.

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32 Figure 3-1. The Sentricon Colony Elimination System was used for monitoring subterranean termite activity in Armstrong Park. The system includes a plastic housing for the in ground stations (a), Monitoring devices equipped with ESP technology (b). Recruit II Baitubes (c) with novi flumuron bait toxicant were used prior to the reinvasion study, and an Interrogator, (d), which detects subterranean termite feeding on ESP equipped monitoring devices. Mark-Recapture and Colony Characterization In the weeks between the monthly inspecti ons of all stations, field-collected cardboard rolls containing termites were taken to the laboratory and processed within 24 hours of collection. Termites were carefully separated from the cardboard roll and associated debris. Termites were sorted by cas te (workers, soldiers, nymphs) and temporarily kept in 0.8L rectangular food storage containers (Rubbermaid, Freeport, IL). The total number of termites collected was calculated based on individual weights determined from worker (5 sets of 20 > 3rd instar) and soldier (1 set of 20) sub-samples. Termites were then placed in 100 x 15 mm Petri

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33 dishes containing filter paper (Whatman No. 1) dyed with either Nile Blue A (0.1% wt/wt), or Neutral Red (0.5% wt/wt), (Fisher Scientific, Pittsburgh, PA). Approximate ly 2 g of termites were placed in each Petri dish and allowed to feed for at least six days, or until the majority of workers had ingested a sufficient amount of dye to make them easily visible in a mixed colony. They were then removed from the Petri dish es, weighed, counted, and released back into the UMS from which they had been collected originally. The re -invading colony foraging territory could then be defined after observing dyed termites in other monitoring stations. Results Reinvading Colony Locations Six reinvading colonies were detected and their foraging territories delineated From October 1, 2003 to March 2, 2005. These reinvading C. formosanus colonies were given numbers from R1 to R6 in the order that they were detected. The first reinvading colony, identified as R1, was detected in the center of the Park on October 1, 2003; the last was detected on January 7, 2005. These colonies appeared in succession throughout the Park (Fig 3.2). Four of these colonies, R1, R2, R4 and R6, were located wel l within the boundaries of the Park. However, two of the colonies, R3 and R5 were located within 5m of the Parks boundary. Dyed individuals were recaptured in every active station. No more than 1 dye color was observed in recaptured individuals of each co lony, indicating that these were all discrete, individual colonies.

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34 Figure 3-2. New C. formosanus colonies detected in Louis Armstrong Park from September 2003 to March, 2005. != C. formosanus colony, != Sentricon monitor Reinvading Colony Foraging Territory Expansion In September 2003 there were no newly detected colonies in the Park. Over the 20 -month period there was a general increase in the overall presence of termites in the monitoring stations within the Park, and in March 2005, 22 of the 81 6 Sentricon monitoring stations revealed C. formosanus foraging activity (Fig. 3.3).

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35 Figure 3-3. Comparison of the number of Sentricon monitoring stations with C. formosanus activity over time in Louis Armstrong Park, New Orleans, LA. The dotted line represents the slope of the linear regression. Reinvading colonies (R1 to R6) are labeled at the date of detection. Four out of the six newly established colonies expanded their foraging territory space vacated by the previously eliminated colonies. Fo ur of the 6 colonies were first detected in a single monitoring station and over time expanded into neighboring monitoring stations. One such example of this behavior is Colony R2 (Fig. 3.4).

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36 Figure 3.4. An example showing expansion of a reinvading C. formosanus colony into new foraging territory from September 2003 to March 2005 in Louis Armstrong Park, New Orleans, LA. Colony R2 was located in the center of the park. !=Activity in a Sentricon in -ground monitoring device. Discussion Time Frame of R einvasion A full elimination of any pest in an area -wide pest management program raises many questions about the possibility, and (more probably) the timeframe of a reinvasion into the vacated area. In this instance, the first sign of reinvasion into Louis Armstrong Park occurred within three months after the full elimination of detectable colonies. The number of newly discovered colonies, their foraging territories, as well as the total amount of termite activity steadily increased over the 20 -month study period.

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37 Undetected Colonies and Incipient Colonies The rapid appearance of new colonies into the study area, especially those well within the park boundary (R1, R2, R4 and R6) suggests that these colonies were already present within the Park, however were previously suppressed by older, larger and more dominant colonies with well-established foraging territories. Rapid reinvasion of newly vacated foraging territories by previously undetected colonies has been observed in previous C. formosanus reinvasion studies (Messenger et al., 2005). Regardless of the presence of incipient colonies, it was observed that new colonies could certainly move into a vacant territory via nuptial flights originating from outside of the treated area (Messenger and Mullins 2004) Factors for Reinvasion Before the full elimination 14 colonies were detected in Armstrong Park, each with a large foraging territory compared to all of the colonies discovered during this study (Messenger and Su, 2005a). With only 6 colonies, occupying an increasing, but still relatively small foraging territory, the total population of C. formosanus in Armstrong Park during this study was considerably lower than prior to the full elimination. After 20 months the Park had 43% of the original number of c olonies. The question remains as to how long would it take for the park to return to its previous, undisturbed population (Fig. 3.4). Figure 3.4 shows a typical logistic growth curve observed by an invasive species introduced into a new environment. The lo gistic growth curve is defined by the function P ( t; a m n,") = a 1 + me# t /"1 + ne# t /" Where population (P) is dependent on parameters a, m, n, and The curve shows logarithmic growth tapering off at the carrying capacity of the environment. The propos ed population of C. formosanus before, immediately after, and at the end of this study is indicated.

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38 Figure 3-5. A typical population logistic growth curve showing the hypothetical population of C. formosanus in Armstrong Park. The proposed populations a re labeled before the full elimination (a), the population immediately following the full elimination (b), and the proposed current status of C. formosanus at the end of the study (c). In order to determine the carrying capacity of an environment for a sp ecies, many factors should be considered: including resources, harborage, interspecific and intraspecific competition and aggression, predation, fecundity and dispersal. Further study into these subjects in a unique test area such as Armstrong Park could p rovide more valuable information in the subject of area wide management of C. formosanus and other subterranean termite species.

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39 CHAPTER 4 MORPHOMETRIC CHARACT ERIZATION OF REINVAD ING COLONIES FOLLOWI NG AREA-WIDE COLONY ELIMINATION Introduction Reinvasion of Vacant Territories Following Area -Wide Colony Elimination The primary objective of this study was to determine the mode of reinvasion following area -wide elimination of detectable colonies. Two scenarios were likely: first, reinvasion via small, col onies recently founded by alate pairs that had flown into the Park, this scenario may also include small, concealed, or otherwise undetectable colonies that had been founded by an alate pair before the full elimination, and which were undetectable prior to the study period. The second scenario is reinvasion via large, established colonies expanding their foraging territory from outside of the Park in the absence of intraspecific, intercolonial competition from the eliminated colonies (Messenger et al. 2005) In order to determine the type of reinvading colony, it becomes important to characterize reinvading colonies using some means of determining the relative age of the reinvading colonies, compared to the age of the eliminated colonies. Morphometry and Colony Characterization Wet body mass and mahalanobis distances have been used in the past to delineate and characterize field -collected colonies of C. formosanus for experimentation (Su and Scheffrahn, 1987; Husseneder and Grace, 2001; Messenger and Su, 200 5a). Although the use of multilocus DNA fingerprinting is a superior means of identifying colony genetic affiliation (Husseneder and Grace, 2001), it does not give an estimation of colony age or size. Population growth estimates for incipient colonies ran ge from approximately 1,000 up to 9,000 individuals within the first three years of growth (Su and Tamashiro, 1987). In addition to population growth, individual termites in a foraging population also increase in size and mass with the age of a colony (Grace et al 1995, Nakajima et al. 1963). According to Raina et al.

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40 (2004), C. formosanus gain an additional antennal segment with each molt. A 1st instar larvae having 11 antennal segments per antennae, and a final -molt imago having 18. Therefore younger colonies with a foraging population made up of 1st to 4th instar nymphs and workers would exhibit fewer antennal segments when compared to an older colony with an older foraging population. In addition, younger foraging populations have a lower individual wet body mass than larger more established colonies (Grace et al 1995, Nakajima et al. 1963). Therefore a young colony should exhibit a lower wet body mass, and a lower antennal segment count when compared to an older colony with an older foraging population. Materials and Methods Morphology Measurements Morphometric data of re -invaded colonies (R1 -R6) were collected to determine the relative age of these re-invaders of the territories previously occupied by older colonies eliminated in 2003. In 2002, a sample of 20 live foraging workers were collected from in -ground stations representing each of the 14 C. formosanus colonies characterized by Messenger and Su (2005a) (Fig.4.1a). These termites were individually weighed. They were then preserved in 75% isopropyl alcohol and the total of left and right antennal segments were counted. In July 2005, another 20 individuals from each of the six reinvading colonies (Fig. 4.1b) were collected and individual body weights and antennal segment counts were recorded.

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41 Figure 4-1. Two aerial maps Of Louis Armstrong Park showing C. formosanus colonial territories of the original 14 colonies eliminated in 2002 -2003 (a), and the reinvading colonies present in the summer of 2005 (b). Figure 4-2. Eliminated and reinvading C. formosanus colonies in Louis Armstrong Park, showing three areas with colonial foraging territory overlap or near -overlap.

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42 Morphology Data analysis Three areas in the Park showed overlap or near -overlap of eliminated versus reinvading colonial territories tha t were present in the park following the full elimination. Morphological data was analyzed for significant differences between original colonies and re -invading colonies occupying the same territory using a t -test at alpha=0.05. The non -parametric Mann -Whitney rank sum test was used in cases when the data did not exhibit a normal distribution sufficient for a t-test. These calculations were performed using Sigma Stat statistical software (Systat Software, Inc. San Jose, CA). Results Original Colonies Vers us Reinvading Colonies Of the six colonies present in the Park in the summer of 2005, (Fig. 4.1a) three of the colonies were occupying, foraging territories previously occupied by large, established colonies that were eliminated in 2003. (Fig. 4.2) These c olonies are designated R2, R3, and R6. Colonies R2 and R6 both reinvaded the vacant foraging territory formerly occupied by the eliminated colony F8. When compared, it was found that R2 was significantly larger than F8 in both wet weight and antennal segme nt count (Table 4.1). Reinvading colony R6 was significantly smaller in antennal segments and body weight than original colony F8 (Table 4.2). Colony R3 reinvaded the territory formerly occupied by colony F 2. The statistical analysis of these two colonies did not show a significant difference in size or antennal segments (Table 4.3)

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43 Table 4 -1. Statistical analysis of morphological characteristics of original C. formosanus colony F8 vs. reinvading colony R2 in overlapping area 1 of Armstrong Park. The re invading colony is significantly larger than the original colony in both wet weight and antennal segment counts. Measurement Original colony F8 Mean/stdev. Reinvading colony R2 Mean/stdev. t value p value # Antennal segments 28.43 30 .19 315.5 P 0.0 11 Wet weight (mg) 2.77 .41 3.247 .32 4.097 P<0.001 Table 4 -2. Statistical analysis of morphological characteristics of original C. formosanus colony F8 vs. reinvading colony R6 in overlapping area 2 of Armstrong Park. The reinvading colony is significantly smaller than the original colony in both wet weight and antennal segment counts. Measurement Original colony F8 Mean/stdev. Reinvading colony R 6 Mean/stdev. t value p value # Antennal segments 28.43 26.6 554.5 P<0.001 Wet weight (mg ) 2.77 .41 2.216 .24 4.097 P<0.001 Table 4 -3. Statistical analysis of morphological characteristics of original C. formosanus colony F2 vs. reinvading colony R3 in overlapping area 2 of Armstrong Park. The reinvading colony is not significantly different than the original colony in wet weight nor antennal segment counts. Measurement Original colony F8 Mean/stdev. Reinvading colony R 3 Mean/stdev. t value p value # Antennal segments 28.1.25 27.96 421 P=0.776 Wet weight (mg) 3.5 .0.22 3.5 .36 479 P=0.064

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44 Figure 4-3. A box plot of individual worker wet mass from all of the original colonies (20 workers per colony, pooled data) in Armstrong Park (F0), compared to the reinvading colonies R1 through R6. The box in each data s et indicates the interquartile range of the data. The Median of the data is indicated as a line within the box, and the whiskers above and below the boxes indicate the upper and lower quartile. Discussion Relative Age of Reinvading Colonies Morphometric data from area 2, comparing the reinvading colony R6 to F8 revealed that the reinvading colony was significantly smaller, and had significantly fewer antennal segments than the original colony (Table 4.1). This indicates that R6 is smaller, and therefore y ounger (Grace et al 1995, Nakajima et al. 1963) than the original colony. This suggests that it must be an incipient colony, founded by alate pairs flying into the Park following the area wide elimination, or it was a small, undetected colony prior to the full elimination. In area 1, however the Individual worker wet weight (g) F0

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45 interpretation is not clear -cut. Workers of reinvading colony R2 are bigger, and therefore the colony may be older than the original colony occupying that territory. However, the territories did not overlap exactly, rather were very close in proximity to one another. One explanation could be that reinvading colony R2 was present and established prior to the full elimination, however avoided detection. Because it is located adjacent to the Performing Arts Building, it is possible that the building provided refuge for colony R2 prior to the full elimination, and then the colony expanded its territory outside of the structure in the years following the elimination of the existing colony F8. In area 3, Colony R3 showed no significant difference in size nor antennal segment counts than its predecessor. This suggests that it was an established colony prior to the full elimination, and expanded its foraging territory into the Park from the outside in the absence of intrasp ecific, intercolonial competition from colony F -2. This is consistent with the location of the reinvasion, which is on the perimeter of the Park. When the wet mass data of the eliminated colonies was pooled, and sub samples of the reinvading colonies was compared using descriptive statistics in a box -plot It becomes relatively clear that three of the reinvading colonies, R1, R2 and R3 do not differ much from the original in individual body weights. This indicates that all three of these colonies were prese nt, in some form, prior to the full elimination. In the case of colony R3, again taking its proximity into account it is likely a large colony moving into the Park from the outside. However, R1 and R2 were first detected near the center of the Park. It is thus likely that both of these colonies were present inside the park, but remained hidden because they were out competed by original colonies and thus were not readily detected before the total elimination.

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46 Colonies R4, R5, and R6 being of significantly sm aller body size, are likely to be new colonies (Fig. 4.3). These were likely founded after or just prior to the full elimination, in the absence of intraspecific, intercolonial competition with dominant colonies. An interesting observation of the data, w hich are consistent with the timeline of the reinvasion, is the order of when the reinvading colonies were detected, and colony size. R1 through R6 were numbered in order of detection, with R1 being detected within months of the full elimination and R6 bei ng detected near the end of the study period (Fig. 3.3). It is evident that the first colonies detected were those that were already established, and began expanding their foraging territory, while those discovered later in the study were of much smaller b ody size, and were likely at the beginning stages of foraging territory establishment.

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47 CHAPTER 5 CONCLUSIONS When properly implemented, area -wide integrated past management (IPM) of a pest species has many advantages. Area -wide IPM usually provides a long er-term and more cost effective solution to targeted pest control than remedial control methods. It also usually provides a more sustainable population control of the targeted pest over time, reducing the number and intensity of pest outbreaks. Also, area -wide IPM often results in an overall reduction in unnecessary pesticide use (Chandler and Faust, 1998). The implementation of an area -wide IPM program requires specific knowledge of the biology and ecology of the targeted pest species in order to correctly design and carry out a successful program. Following the area -wide elimination of all detectable C. formosanus colonies in Louis Armstrong Park, a vacant niche remained where a long -standing population of C. formosanus once existed. In the absence of this population there was no question that the niche would be filled by reinvading populations. However the questions remained: How would such a reinvasion take place? And how quickly would it occur? In this study, Louis Armstrong Park was used as a test sit e in order to observe the succession of C. formosanus populations following area -wide colony elimination. The original objectives of this particular study were: 1. To examine the mode of reinvasion via imagoes following dispersal flights from outside of the Park. 2. To document how quickly C. formosanus would reinvade the Park. 3. To determine whether the Park would be reinvaded by older, more established colonies moving in from foraging territories located adjacent to the Park, or by smaller, incipient colonies founded by alate pairs that may have flown into the Park and are able to expand

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48 their range in the absence of intraspecific, intercolonial competition with established colonies within the study area. In Chapter two of this thesis, the first objective was di scussed. Alate populations decreased following the full elimination, and nuptial pairs were discovered in monitoring devices once occupied by eliminated colonies. Evidence suggests that the dispersal flights of these new potential colonies originated from outside of the treated area. Five such nuptial pairs were discovered within the first year of colony elimination. The majority of these were discovered within the first 5 months. No such pairings were detected throughout the rest of the study. In other sce narios the dispersal flight season of C. formosanus must be considered; however there appeared to be a window of opportunity of approximately one year where new colonies will be established via dispersal flights of imagoes into the newly vacated niche. In the race of new colonies to occupy newly vacated territory and resources, intraspecific, intercolonial aggression with conspecific neighbors has been observed in ants. Though the cryptic behavior of termites prevents such direct observation from taking p lace, it is proposed that increased intraspecific, intercolonial competition after one year is the reason further nuptial pairs were not observed with the sampling method. Within two years of colony elimination six distinct colonies were documented and characterized within Armstrong Park. The third chapter of this thesis discussed the discovery and expansion of these colonies over time (Figs. 3.2, 3.3). These findings demonstrated that nearly two years after area -wide elimination, the population of reinvadi ng C. formosanus was increasing, however, with only up to 43% of the original number of colonies, it was not near the

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49 carrying capacity of the Park. A typical logistic growth curve was presented with a proposed status of the growing population as of March 2005 (Fig. 3.4). The third objective of this study was discussed in the fourth chapter of this thesis. In order to answer the question of whether the Park would be reinvaded by older, established colonies moving in from outside the treated area, or by sma ll, incipient colonies established by nuptial pairs flying in from outside the park, morphological data was collected from the six reinvading colonies. This morphological data suggests that both reinvaded the Park. The first two reinvading colonies detecte d were actually present, but were suppressed and undetectable prior to the full elimination. However, both colonies quickly became detectable after all previously detectable colonies were eliminated from the Park. The proximity of nearby structures could h ave provided hidden refuge for the colonies prior to the elimination. Thorough inspections and the use of aboveground bait stations could have potentially prevented this from occurring. The third colony that was detected was likely an established colony ex panding its territory from outside of the Park in the absence of intraspecefic, intercolonial competition from established colonies in the treated area. The final three colonies were small, and likely were new colonies established by alate nuptial pairs fl ying into the Park just prior to, or just after the full elimination. This study provides a snapshot of what happens immediately after area -wide management of subterranean populations is implemented. In this study, further baiting was ceased following the initial elimination. Presumably, correctly implemented area -wide subterranean termite control measures would include continued baiting upon the detection of new colonies. In addition, the use of structural inspections and aboveground baiting stations would have increased the efficacy of the full elimination. Potentially slowing the initial reinvasion of the Park. However, after 20 months of the full elimination the population recovery of C. formosanus in the

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50 Park was well underway. Further monitoring of the Park and documentation of new colonies and colony expansion may provide a more robust insight into the succession ecology of subterranean termites and other social insects following such an endeavor.

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51 LIST OF REFERENCES Beal, R. H., and V. K. Smith. 1971. Relative susceptibilities of Coptotermes formosanus, Reticulitermes flavipes and R. virginicus to soil insecticides. J. Econ. Entomol. 64: 472 475. Bess, H. A. 1970. Termites of Hawaii and the oceanic islands. Pp. 449 -476 In K. Krishna & F. M. Weesner [eds.], Biology of termites, Vol. 2. Academic Press, New York and London. Brown, K. S., B. P. Yokum, C. Riegel, and M. K. Carroll. 2007. New parish records of Coptotermes formosanus (Isoptera: Rhinotermitidae) in Louisiana. Florida Entomol. 90: 570-572. Chambers, D. M., P.A. Zungoli, and H. S. Hill, Jr. 1988. Distribution and habitats of the Formosan subterranean termite (Isoptera: Rhinotermitidae) in South Carolina. J. Econ. Entomol. 81: 1611 -1619. Chandler, L. D., and R. M. Faust. 1998. Overview of area-wide management of insects. J. Agric. Entomol. 15: 319 -325. Edwards, R., and A. E. Mill. 1986. Termites in buildings. Their biology and control. Rentokil Ltd. W. Sussex UK, pp. 261 Gordon, D. M. 1991. Behavioral flexibility and the foraging ecology of seed-eating ants. Am. Nat. 138: 379-411. Grace, J. K., R. T. Yamamoto, and M. Tamashiro. 1995. Relationship of worker mass and population decline in a Formosan subterranean termite colony (Isoptera: Rhinotermitidae). Environ. Entomol. 24: 1258 -1262. Grace, J. K., and A. Abdallay. 1990. A short-term dye for marking eastern subterranean termites, Reticulitermes flavipes Kollar (Isoptera: Rhinotermitidae). J. Appl. Entomol. 109: 71-75. Henderson, G. 1996. Alate production, flight phenology, and sex -ratio i n Coptotermes formosanus Shiraki, an introduced subterranean termite in New Orleans, Louisiana. Sociobiology 28: 319 -326 Hlldobler, B. and C. J. Lumsden. 1980. Territorial strategies in ants. Science 210: 732 -739. Husseneder, C., and J. K. Grace. 2001. Evaluation of DNA fingerprinting, aggression tests, and morphometry as tools for colony delineation of the Formosan subterranean termite. J. Insect Behav. 14: 173 -186.

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52 Husseneder, C., M. T. Messenger, N.-Y. Su, J.K. Grace, and E. L. Vargo. 2005. Colony social organization and population genetic structure of an introduced population of Formosan subterranean termite from New Orleans, Louisiana. J. Econ. Entomol. 98: 1421-1434. Kistner, D. H. 1985. A new genus and species of termitophilus Aleaocharinae f rom mainland China associated with Coptotermes formosanus and its zoogeographic significance (Coleoptera: Staphilinidae). Sociobiology 10: 93 -104. La Fage, J. P. 1987. Practical considerations of the Formosan subterranean termite in Louisiana: A 30-year problem, pp. 37 -42. In M. Tamashiro and N.-Y. Su [eds.], Biology and control of the Formosan subterranean termite. College of Tropical Agriculture, Human Resources, University of Hawaii, Honolulu, HI. Lai, P. Y., M. Tamashiro, J. K. Fujii, J. R. Yates, and N.-Y. Su. 1983. Sudan red 7B, a dye marker for Coptotermes formosanus. Proc. of Hawaiian Entomol. Soc. 24: 277 -282. Lax, A. R. and W. L. Osbrink. 2003. United States Department of Agriculture Agricultural Research Service research on targeted manageme nt of the Formosan subterranean termite Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Pest Manag. Sci. 59: 788 800. Messenger, M. T. 2002. The termite species of Louisiana: an identification guide. New Orleans Mosquito and Termite Control B oard. Bull. No. 01-01. 2nd ed. 12pp. Messenger, M. T., and N.-Y. Su. 2005a. Colony characteristics and seasonal activity of the Formosan subterranean termite (Isoptera: Rhinotermitidae) in Louis Armstrong Park, New Orleans, Louisiana. J. Entomol. Sci. 40 : 268-279. Messenger, M. T., and N.-Y. Su. 2005b. Agonistic behavior between colonies of the Formosan subterranean termite (Isoptera: Rhinotermitidae) from Louis Armstrong Park, New Orleans, Louisiana. Sociobiology 45: 331 -345. Messenger, M. T., N.-Y. Su, C. Husseneder, and J. K. Grace. 2005. Elimination and reinvasion studies with Coptotermes formosanus (Isoptera: Rhinotermitidae) in Louisiana. J. Econ. Entomol. 98: 916 -929. Messenger, M. T., and A. J. Mullins, 2005. New flight distance recorded for Coptotermes formosanus (Isoptera: Rhinotermitidae). Florida Entomol. 88: 99 -100. Nakajima, S., K. Shimizu, and Y. Nakajima. 1963. Analytical studies on the vitality of colonies of the Formosan termite. Coptotermes formosanus Shiraki. Bull. Fac. Agr., Univ. Miyazaki 8: 106 -110

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53 Osbrink, W. L. A., W. D. Woodson, and A. R. Lax. 1999. Populations of Formosan subterranean termite, Coptotermes formosanus (Isoptera: Rhinotermitidae), established in living urban trees in New Orleans, Louisiana, USA., pp. 341 -345. In W. H. Robinson, F. Rettich, and G. W. Rambo [eds.], Proc. 3rd International Conference on Urban Pests, Czech Republic: Graficke zavody hronov. Oshima, M. 1919. Formosan termites and methods of preventing their damage. Phillipine J. Sci. 15: 319-383. Raina, A. K., J. M. Bland, J C. Dickens, Y. I. Park, and P. Hollister. 2003. Premating behavior of dealates of the Formosan subterranean termite and evidence for the presence of a contact sex pheromone. J. Insect Behav. 16: 233 -245. Raina, A., W. Osbrink, and Y. I. Park. 2004. Nymphs of the Formosan subterranean termite (Isoptera: Rhinotermitidae): aspects of formation and transformation. Ann. Entomol. Soc. Am. 97: 737-764. Scheffrahn, R. H., J. R. Mangold, and N. -Y. Su. 1988. A survey of structure-infesting termites of peninsular Florida. Florida Entomol. 71: 615 -630. Shelton, T. G., and J. K. Grace. 1997. Suggestion of an environmental influence on intercolony agonism of Formosan subterranean termites (Isoptera: Rhinotermitidae) Environ. Entomol. 26: 632 -637. Smith, J., N.-Y Su, and R. N. Escobar. 2006. An areawide population management project for the invasive eastern subterranean termite: (Isoptera Rhinotermitidae) in a low -income community in Santiago, Chile. Am. Entomol. 52: 253 -260. Spink, W. T. 1967. The Formosan subterranean termite in Louisiana. Circular No. 89, Louisiana Agricultural Experiment Station, Baton Rouge. 12 pp. Su, N.-Y. M. Tamashiro, J. R. Yates, and M. I. Haverty. 1984. Foraging behavior of the Formosan subterranean termite (Isopt era: Rhinotermitidae). Environ. Entomol. 13: 1466 1470. Su, N.-Y., and R. H. Scheffrahn. 1986. A method to access, trap, and monitor field populations of the Formosan subterranean termite (Isoptera: Rhinotermitidae) in the urban environment. Sociobiology 12: 299-304. Su, N.-Y., and R. H. Scheffrahn. 1987. Alate production of a field colony of the Formosan subterranean termite (Isoptera: Rhinotermitidae). Sociobiology 13: 209 -215. Su, N.-Y., and M. Tamashiro. 1987. An overview of the Formosan subterranean termite in the world, pp. 3-15. In: M. Tamashiro and N. -Y. Su [eds.], Biology and control of the Formosan subterranean termite. College of Tropical Agriculture, Human Resources, University of Hawaii, Honolulu, HI.

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54 Su, N.-Y., and R. H. Scheffrahn. 1988. Intraand interspecific competition of the Formosan and the eastern subterranean termite: evidence from field observations (Isoptera: Rhinotermitidae). Sociobiology 14: 157 -164. Su, N.-Y., and R. H. Scheffrahn. 1988. Foraging population and territory of the Formosan subterranean termite (Isoptera: Rhinotermitidae) in an urban environment. Sociobiology 14: 353-359. Su, N.-Y., R. H. Scheffrahn, and P. M. Ban. 1989. Method to monitor initiation of aerial infestations by alates of the Formosan subterranean termite (Isoptera: Rhinotermitidae) in high-rise buildings. J. Econ. Entomol. 82: 1643 -1645. Su, N.-Y., and R. H. Scheffrahn. 1990. Economically important termites in the United States and their control. Sociobiology 17: 77 -94. Su, N.-Y., P. M. Ban, and R. H. Scheffrahn. 1993. Foraging populations and territories of the eastern subterranean termite (Isoptera: Rhinotermitidae) in southeastern Florida. Environ. Entomol. 22: 1113 -1117. Su, N.-Y. 1994. Field evaluation of a hexaflumuron bait for po pulation suppression of subterranean termites (Isoptera: Rhinotermitidae). J. Econ. Entomol. 87: 389 -397. Su, N.-Y. 2003a. Overview of the global distibution and control of the Formosan subterranean termite. Sociobiology 41: 7 -15. Su, N.-Y. 2003b. Baits as a tool for population control of the Formosan subterranean termite. Sociobiology 41: 177 -192. Su, N.-Y., P. Ban, and R. H. Scheffrahn. 2004. Use of a bait impact index to assess effects of bait application against populations of Formosan subte rranean termite (Isoptera: Rhinotermitidae) in a large area. J. Econ. Entomol. 97: 2029 -2034. Su, N.-Y. 2005. Response of the Formosan subterranean termite (Isoptera: Rhinotermitidae) to baits or nonrepellent termiticides in extended foraging arenas. J. E non. Entomol. 98: 2143-2152. Suzkiw. J. 1998. The Formosan termite. A formidable foe. Agr. Res. 46: 4 -9. Sweezy, O. H. 1914. Notes and exhibitions. Proc. Hawaii. Entomol. Soc. 3: 27. Tamashiro, M., J. K. Fujii, and P.-Y. Lai. 1973. A simple method to ob serve, trap, and prepare large numbers of subterranean termites for laboratory and field experiments. Environ. Entomol. 2: 721 -722.

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55 Woodson, W. D., B. A. Wiltz, and A. R. Lax. 2001. Current distribution of the Formosan subterranean termite (Isoptera: Rhin otermitidae) in the United States. Sociobiology 37: 661-671.

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56 BIOGRAPHICAL SKETCH The author began his fascination with insects as a child. Receiving his first beehive as a 4 H project at age 9. His interest in biology, in particular the social insects, c ontinued through an undergraduate degree in biology with a minor in chemistry and entomology at Virginia Tech. Following his undergraduate he served as a United States Peace Corps Volunteer, working with small land holding farmers in a remote village in No rthwestern Ecuador for two years. Upon his return he worked as a seed chemist for Busch Agricultural Resources Inc. in Fort Collins, Colorado before relocating to New Orleans, LA for a job with the New Orleans Mosquito and Termite Control Board. During his 5 years in the City of New Orleans, he worked primarily with the Formosan Subterranean Termite, conducting field ecology research in city parks. The author currently resides in his hometown of Blacksburg, VA and is Research Faculty in the Virginia Tech Apiculture Program.

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SUCCESSION ECOLOGY OF COPTOTERMES FORMOSANUS SHIRAKI FOLLOWING AREA-WIDE COLONY ELIMINATION Aaron James Mullins (540) 239-2427 Entomology and Nematology Nan-Yao Su Master of Science August 2009 The Formosan Subterranean Termite is a s ignificant economic pest in the southeastern United States. It is known to cause millions of dollars in damage to houses and buildings annually. Much of this damage is located in Louisiana and Florida. A new approach to control of this pest species is Area -Wide Management. This approach involves using pest control strategies unique to the behavior and biology of the target pest in order to control the overall population in a given area. Such a large -scale control effort requires some basic knowledge of the Ecology of the target pest. Of particular interest is the speed and facility of the pest to re -invade an area following such an effort. This study has culminated in a bet ter understanding of the reinvasion of a test area following Area -Wide population cont rol of the Formosan Subterranean Termite.