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Copyright 2005, Board of Trustees, University
Stinging or Venomous Insects
and Related Pests
P. G. Koehler and D. E. Short
Florida Cooperative Extension Service
Institute of Food and Agriculrural Sciences
University of Florida, Gainesville
John T. Woeste, Dean for Extension
Millions of people in the United States are in-
jured from venoms produced by insects and other
arthropods each year. Of these injuries about
25,000 result in severe injuries and about 32 re-
sult in deaths (Table 1).
Table 1. Deaths from Venomous Pests (from Parrish
Percent of Total
Snakes 13.8 30
Insects and Related Pests 32.2 66
Bees 12.4 27
Wasps 6.9 15
Spiders 6.5 14.1
Yellow Jackets 2.2 4.8
Hornets 1.0 2.2
Scorpions 1.0 2.2
Ants 0.4 0.8
Others 1.8 4
Venomous insects and other arthropods produce
venoms which can be classified as:
(1) Venoms which produce blisters (Vesicat-
ing Toxins) (e.g., blister beetles, certain
stinging caterpillars, millipedes).
(2) Venoms which attack the central nervous
system (Neurotoxins) (e.g., black widow
spiders, bark scorpions, certain ticks, Hy-
menoptera, wheel bugs).
(3) Venoms which destroy tissue (Cytolytic
and Haemolytic) (e.g., Hymenoptera, fire
ants, ground scorpions, mites, chiggers,
wheel bugs, brown recluse spider).
(4) Toxins that prevent blood from clot-
ting (Haemorrhagic) (e.g., lice, fleas, ticks,
mites, true bugs, biting flies).
Humans differ greatly in their reaction to ar-
thropod venoms. Allergic reactions are often
more important than the toxic effects of arthro-
pod venoms. Of individuals who die from ar-
thropod venoms, 96% had an allergic reaction.
Prepared by P. G. Koehler and D. E. Short,
Assistant Professor- Extension Entomologist, re-
spectively; Department of Entomology and Nema-
tology, University of Florida, Gainesville.
Allergic reactions to stings or bites are when
something happens to a part of the body other
than the immediately affected area. Allergic re-
actions are classified according to the severity of
the body's reaction as:
1. Slight general reaction inflammation,
wheals, itching, malaise, and anxiety.
2. General reaction-a slight general reaction
+2 or more of swelling, wheezing, abdomi-
nal pain, nausea and vomiting.
3. Severe general reaction-any of the above
+2 or more of difficulty in breathing, diffi-
culty in swallowing, hoarseness, confusion,
or feeling of impending disaster.
4. Shock reaction-any of the above+2 or more
of cyanosis, fall in blood pressure, collapse,
unconsciousness, or incontinuance.
Insect stings result in rapid progression of toxic
effects. Of 208 deaths, 80% occurred less than one
hour after being stung by Hymenoptera (bees,
wasps, yellow jackets or hornets). Spider bites,
however, have a longer time interval between
bites and time of death with 89% of 54 victims
dying more than 12 hours after being bitten. Sta-
tistics also reveal that of snakebite victim deaths,
17% died 1-12 hours after being bitten and 64%
between 12 hours and 2 days.
What To Do
Insect stings require quick, prompt action.
(1) The causative organism must be captured,
saved and identified.
(2) If a general allergic reaction is suspected,
or the victim has a history of hayfever,
allergy, or asthma, a doctor should be con-
tacted immediately. Additional medical in-
formation on poisonings can be obtained
from the Center for Disease Control, At-
lanta, Georgia (404-633-3311) or the local
Poison Control Center.
(3) If marked swelling or discoloration occurs
at site of bite or sting, the venom is prob-
ably haemolytic, haemorrhagic, or vesicat-
ing. Keep victim warm and quiet until phy-
sician is reached.
(4) If little or no swelling or discoloration oc-
curs at site of bite or sting, the venom is
probably neurotoxic. Apply ice to site or
immerse affected part of body in ice water
until physician is reached.
(5) Persons who have exhibited a severe al-
lergic reaction in the past to arthropod
venoms or have a history of asthma, hay-
fever, or allergies should:
Figure 1. Honey bee on rape blossom (Photo courtesy
of Mr. Frank Robinson).
Figure 2. Bumblebee (Photo courtesy of Dr. James E.
Figure 3. Yellow jacket capturing cuban green cock-
roach (Photo courtesy of Dr. James E. Lloyd).
a) Undergo skin testing to determine hy-
persensitivity to arthropod venoms.
b) Carry identification or tags noting hy-
c) Consider desensitization (immuniza-
d) Carry an insect sting kit (available
only with a physician's prescription).
Prevention of Stings
Several procedures can be used to minimize the
danger of being stung by venomous arthropods.
(1) Avoid mowing lawns or working with
flowering ornamentals when bees and
wasps are collecting nectar.
(2) Don't walk in the yard in bare feet.
(3) Sweet items like soft drinks, ripened fruits
and watermelons attract bees and wasps.
Keep these items covered outdoors. Pick
fruit as it ripens or dispose of rotten fruits.
(4) Stand still if a stinging insect is near you.
If it attacks, brush it off (don't slap) to
prevent a sting.
(5) Control stinging arthropods near heavily
(6) If attacked by a swarm of bees, wasps,
yellow jackets or hornets, leave area im-
mediately using arms to protect your face.
Some Common Venomous Arthropods
Pertinent information on common venomous
arthropods is found in Table 2.
Bees-Bees are often confused with wasps. Al-
though closely related, they differ in many ways.
Bees feed pollen and nectar to their young. They
are beneficial insects that pollinate fruits, vege-
tables and many other plants.
The most common bees are the honey bee, bum-
ble bee and carpenter bee. Bees are not commonly
serious problems and usually require no control.
When stung by a honey bee, scrape the bee's
stinger out of the wound immediately. Be careful
not to pull it out. If you do, you will force poison
into the wound. If the stinger is not removed, the
poison gland attached to the stinger will continue
to pump poison into the wound for several min-
utes. Wasps and other bees do not leave a stinger
and are capable of stinging many times.
At certain times of the year (spring and early
summer), honey bee colonies divide by swarming.
Swarms are not usually a problem unless they
land in an inconvenient spot or enter a building.
A honey bee colony in a building must be removed
after it has been killed to prevent problems from
odors of decaying bees, honey, and other pests.
If a bee swarm is undesirable in trees, shrub-
bery or buildings, you may wish to contact a bee-
keeper, county agent, or pest control company to
remove or kill it. Insecticide dusts are effective
for killing bee colonies in buildings. Carbaryl
(Sevin), diazinon, and malathion dusts may be
applied for effective control.
To control bees:
1) Locate the colony in the wall at night by
tapping and listening for the area of loudest
buzzing. Bees also keep the nest at 950 so
you may be able to feel the heat through the
2) At night, drill a small hole in the wall above
the colony and apply dust through it or
apply to honey bee entrance to colony.
3) Seal all entrances and exits from the colony.
4) After 2 weeks or when all sound and bee
activity has stopped, open the wall and
remove dead bees, comb, and honey.
5) Bury the colony so valuable honey bee colo-
nies will not be attracted to the residue
Wasps-Hornets, yellow jackets, Polistes, mud
daubers, and the cicada killers are all wasps. They
are generally considered to be beneficial because
they attack and destroy many harmful insects
found around homes and gardens. Hornets and
yellow jackets kill such pests as house flies, blow
flies, and various caterpillars. Polistes are pre-
dators of corn earworms, armyworms, and many
other garden pests. Though beneficial, wasps also
attack people. If disturbed, hornets, yellow jackets
and Polistes will sting. Mud daubers and cicada
killers usually are not as aggressive and will not
sting unless touched or accidentally caught in
clothing. If wasps build nests on houses or in
bushes where children play or living activities are
carried on, nest destruction or chemical control
Wasps can usually be identified by the nests
they construct and where they construct them.
Hornets, Polistes and mud daubers build nests
above the ground. Hornets and Polistes nest in
trees, shrubbery and under eaves. Mud daubers
nest under eaves, porch roofs, or similar sheltered
areas. Yellow jackets usually build their nest in
the ground, but sometimes build them above the
ground. Cicada killers nest in the ground.
Figure 4. Yellow jacket nest.
Figure 5. Polistes paper wasp and nest (Photo courtesy
of Dr. James E. Lloyd).
Figure 6. Mud dauber wasp feeding on raspberry (Photo
courtesy of Dr. James E. Lloyd).
Figure 7. Cicada-killer wasp (Photo courtesy of
Dr. James E. Lloyd).
Hornets and yellow jackets build football-
shaped paper-like nests. Polistes build paper-like
nests that resemble a honeycomb. Mud daubers
build clay or mud-cell nests. Cicada killers dig
homes about one half inch across and pile the ex-
cavated soil around the opening.
Hornets, yellow jackets and Polistes are social
insects and their colonies develop in a similar way.
Adult females make up two castes-queen or fer-
tile females which lay eggs; workers or sterile
females which feed larva and may lay eggs with-
out mating if the queen dies during the season.
In the fall, queens and males leave the nest and
mate. The male dies and the surviving queens
hiberate in cracks of rocks, under bark of trees,
in buildings or in the ground. In the spring the
queen comes out of liberation and builds a nest
with a few shallow cells. An egg is laid in each
cell and these hatch into worker larvae in 2 to 3
days. The queen feeds these larvae which develop
in 12 to 18 days and spin cocoon caps over the
cells and change into pupae. After the first brood
emerges the queen resumes egg laying. The work-
ers take charge of the nest, enlarging it and car-
ing for the new larvae.
Mud daubers are solitary wasps. Each female
constructs a clump of mud cells. There is no work-
er caste. In the spring young adults come out of
their nests and mate. The females then build mud-
cell nests. After she completes the nest she cap-
tures about 20 spiders, paralyzing each with her
sting as she catches it. These are stored in the
cell and she lays an egg on one of the spiders and
caps the cell with clay. This is repeated until she
has built one nest containing 6 to 20 cells. She
may then build other nests in other locations.
Table 2. Summary of Important Stinging Arthrodpods.
Pest Description Nest Ability
Honey Bee 2/3 in., yellow and black or brown, Made of wax cells, found in Yes
body covered with hairs. wall voids or under slab
Bumble Bee 1 in., black and yellow body Made of wax cells, below Yes
covered with hair. ground, under slabs,
in wall voids.
Hornets and 3/4 in., black with yellow or white Made of papery material. Nests Yes
Yellow Jackets markings. either aerial or below ground
or both. Nests large and
Table 2. (cont.)
Pest Description Nest Ability
%-1 in., black or brown with red
and a few with small
%-1 in., black and yellow, or
metallic blue, or shiny black.
112 in., black with yellow
1-4 in., have 10 legs with tail
which bears a stinger.
Depend on species, 8 legs, 2 body
Brown with fiddle-like mark on
cephalothorax, 6 eyes.
Black with red hourglass mark on
underside of abdomen, 8 eyes.
1/16-/4in., yellowish to dark red
with stinger on end of abdomen.
1-11/2 in., cog-like wheel on
top of thorax.
1/2- in. beetle with thorax nar-
rower than head or wings.
Depend on species, usually have
long and short hairs.
Made of papery material. One
circular comb of cells open-
ing downward commonly under
eaves or window ledges.
Made of clay or mud. Usually
along eaves or in garages.
Solitary, digs in soil.
Hide under boards, rubbish
and debris, solitary
Widespread and solitary.
Mounds 3-36 in. high with
Solitary, occur in vegetation
Solitary occur on vegetation.
1/2-1 in., wingless ant-like, covered Solitary on ground.
with hair bright red,
orange or yellow.
not have a
Figure 8. Scorpion (Photo courtesy of Mr. Lewis S.
Figure 9. Brown recluse spider
Mr. Lewis S. Maxwell).
(Photo courtesy of
Figure 10. Black widow spider (Photo courtesy of
Mr. Lewis S. Maxwell).
Once a nest is finished, she leaves it and never
returns. The larvae hatch from the eggs and feed
on the paralyzed spiders. Complete development
takes place in the cell. One to three generations
can develop in a year.
The cicada killer is also a solitary wasp. Its
habits are similar to the mud dauber except it
constructs its cells in the soil and provisions the
cells with cicadas.
When a wasp stings it injects a venomous fluid
under the skin. The venom causes a painful swell-
ing that may last several days. In some cases a
wasp sting may cause severe illness or even death.
Control-Wasps can be easily controlled by ap-
plying insecticides to the nest. However, there is
usually a certain amount of risk. Nests should be
treated at night to minimize the danger of being
stung or protective clothing should be worn. Gen-
erally, sprays are more effective for aerial nests
and dusts are more effective for below ground
nests. Residual sprays recommended for aerial
wasp control are 1% Baygon, 0.5% Vapona, 0.5%
diazinon, 0.5% Dursban, 2% malathion, or 1%
Ronnel (Korlan). Whatever spray is used, it
should have a quick knockdown agent such as
synergized pyrethrum Or Vapona mixed with it.
Dusts recommended for below ground wasp nests
are 2% diazninon, 5% carbaryl (Sevin) and 5%
Control Procedures-For below ground nests,
locate nest and mark area so it is easy to find
after dark. Use a flashlight covered with a red
cellophane paper so wasps stay in their nest. At
night, puff dusts into nest entrance and immedi-
ately throw a shovelful of moist soil over entrance.
Be careful not to step into the nest.
For aerial nests, spray nests with pressurized
containers with a pin-stream spray from a dis-
tance (20 ft.).
Indoor wasp nests should be controlled as
honey bee colonies.
Scorpions-Scorpions are flattened, crab-like ani-
mals having ten legs and a fleshy tail, ending in
an enlarged upturned tip which bears a stinger.
They vary in size from one to four inches long.
They normally live outdoors, though they will
invade homes and buildings.
Scorpions will sting, but usually only when pro-
voked or disturbed. Scorpion venom is a neuro-
toxin, but the dose injected usually is insufficient
to prove fatal to an adult human. None of the sev-
eral species of scorpions which occur in Florida
is capable of inflicting a lethal sting; however, the
site of the sting may be sore and swollen for some
Scorpions are most active at night. They hide
under boards, rubbish, or similar debris which
provide shelter and protection. Places commonly
infested in a home are under the house or in the
attic. They feed on insects, spiders, or similar
small animal life.
Scorpions have a long life cycle. Three to five
years may be normal. Males and females go
through a courtship ritual prior to mating. Scor-
pions do not lay eggs and the young are born alive.
After birth the young scorpions climb on the back
of the mother and remain there until after their
first molt. Scorpions are cannibalistic and will
readily eat other species or smaller individuals of
their own species. Females will often eat their
Control-Mechanically destroy any scorpions
found indoors by swatting or crushing. Clean out
all possible hiding places. Treat hiding or breeding
areas with sprays containing 1% Baygon, 0.5%
diazinon, 2% malathion or dusts containing 5%
malathion or 2% diazinon.
Ducks and chickens will eliminate most scor-
pions from around a building. During dry weather
scorpions can be attracted and trapped by spread-
ing moist burlap on the ground around infested
Spiders-Almost all spiders in Florida are harm-
less to man. Most species do not bite unless pro-
voked to attack. The widow spiders, primarily the
southern black widow and northern black widow,
are the most frequently found venomous spiders.
The brown recluse spider is not considered to be
established in Florida although physicians have
diagnosed its bites on patients. See Entomology
Fact Sheet #26 for additional information on
Fire Ants-Fire ants look like ordinary house
ants; however, they are an aggressive ant capable
of inflicting a painful sting. The colony of im-
ported fire ant is a mound sometimes 3 feet across.
See Entomology Fact Sheet #10 on Ants.
Wheel Bug-The wheel bug is a predacious bug
with a cog-like crest on its thorax. They feed on
insects; however, humans are bitten by accidental
contact. The bug penetrates the skin with its beak
and injects a salivary fluid used to kill its prey.
The fluid causes an immediate intense pain which
lasts 3-6 hours. The best way to prevent wheel
bug bites is to avoid the insect.
Blister Beetles-Blister beetles are narrow beetles
with a neck which is slenderer than the head and
wings. Adult beetles can release a fluid which
causes blisters on human skin. The larvae of
Figure 11. Major worker of fire ant (Photo courtesy of
Figure 12. Wheel bug (Photo courtesy of USAF)
Figure 12. Wheel bug (Photo courtesy of USAF).
Figure 13. Blister beetle (Photo courtesy of Mr. Lewis S.
Figure 14. 10 moth caterpillar (Photo courtesy of
Mr. Lewis S. Maxwell).
Figure 15. Velvet ant
(Photo courtesy of Mr. Lewis S.
blister beetles are harmless to man and are pre-
daceous on other insects. The adult beetles feed
on foliage, and persons often come into contact
when moving through infested vegetation.
The only suitable control of blister beetles is
avoidance of individual beetles or chemical appli-
cation to crop plants. It is necessary to check
recommendations for the crop to determine the
chemical to be used.
Stinging Caterpillars-Stinging caterpillars fre-
quently found in Florida are the puss caterpillar,
saddleback caterpillar, IO moth caterpillar, and
the hag moth caterpillar. These caterpillars feed
on vegetation and have spines which can break
off in the skin. When the spines break, a toxin
flows from the spines onto the skin, causing a
When working in an infested area, wear pro-
tective clothing. See the Extension fact sheet on
"Stinging Caterpillars" for more information.
Velvet Ant-Velvet ants belong to a large family
of wingless, ant-like wasps. The females are soli-
tary, parasitic wasps with an efficient, large sting-
er. Most species are parasitic on solitary bees and
Humans are usually stung by velvet ants when
the female wasp is accidentally stepped on with
bare feet or trapped against the body in clothing
or bedding. Since the wasp is solitary and roam-
ing, control is difficult.
Editor: Keith Hoeller
Graphic Design: Ashley Wood
Cover Photo: Paul Cassidy
Single copies are free to residents of Florida and may be ob-
tained from the County Extension Office. Bulk rates are
available upon request. Please submit details of the request to
C. M. Hinton, Publication Distribution Center, IFAS Building
664, University of Florida, Gainesville, Florida 32611.
This publication was printed at a cost of
$2,746.00 or 27.5 cents per copy to inform the
public about stinging or venomous insects and
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