Transcript Blister Beetle1

Blister Beetle
• The family Meloidae, blister beetles,
contains about 2500 species, divided
among 80 genera and three subfamilies
Description:
• Blister beetles vary by species in shape, size (3/8 to
1 inch long) and color (solid gray to black or with
paler wing margins, metallic, yellowish striped or
spotted).
• Most are long, cylindrical narrow-bodied beetles that
have heads that are wider than the first thoracic
segment (pronotum). The wing (elytra) covers are
usually soft and pliable.
• Although over 100 species occur
in Texas, common blister beetles
include:, the black blister
beetle; Epicauta pennsylvanica
(De Geer), E. occidentalis (east
and central Texas) and E.
temexa (south Texas) are mostly
orangish-yellow with three black
stripes on each of the wing
covers (elytra). A west Texas
species, Cysteodemus armatus
LeConte, has wing covers that
are broadly oval and convex,
colored black with bluish or
purplish highlights.
Blister beetles,
Epicauta sp.
(Coleoptera: Meloidae),
mating on Texas mountain laurel.
Photo by Drees
Life Cycle:
• Complete metamorphosis;
hypermetamorphosis.
Winter is spent in later larval
stages and pupation occurs
in the spring. The pupal
stage lasts about 2 weeks
and adults appear in early
summer. Female beetles lay
clusters of eggs in the soil.
The first stage (instar) larva
hatching from the egg
(triungulin) is a tiny, active,
long-legged larva that seeks
the appropriate host.
Blister Beetle Life Cycle
A = adult, E = egg, T = first instar or
triungulin, FG = first grub phase,
C = coarctate phase in instar six or seven,
SG = second grub phase, P = pupa
Habitat and Food Source(s):
• Mouthparts are for
chewing. Blister beetle
species feed on flowers
and foliage of a wide
variety of crops
including alfalfa,
ornamental plants,
potatoes, garden
vegetables and other
plants.
Black blister beetle,
Epicauta pennsylvanica (DeGeer)
(Coleoptera: Meloidae),
on goldenrod flowers.
Photo by Drees
Medical and Veterinary Importance
• Blister beetles receive their
common name from the
ability of their hemolymph to
produce blistering on contact
with human skin.
Hemolymph is often exuded
copiously by reflexive
bleeding when an adult
beetle is pressed or rubbed.
Blisters commonly occur on
the neck and arms, as the
result of exposure to adult
beetles attracted to outdoor
lights at night.
Pest Status:
• Adults usually occur in loose groups or
swarms that feed on leaves of certain
plants, especially legumes. Their bodies
contain a toxin (cantharadin) that can
cause blisters to form on the skin. Animals,
particularly horses, ingesting beetle
contaminated feed become extremely ill
and may die. Handling blister beetles can
cause blisters on the skin as a reaction to
cantharadin
• Cases of fatal poisonings of valuable
horses in Florida, Oklahoma, Tennessee,
and Texas by ingestion of blister beetles
trapped in baled alfalfa hay
Cantharidin
• Highly toxic to horses, humans, sheep, goats,
canine, feline, cattle.
• Clinical signs usually appear quick- 6-8 hours.
• No specific antidote…. Only supportive care.
• Only takes 6-8 g of dried beetles to be toxic.
Clinical signs:
(include but not limited to)
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Colic symptoms-abdominal pain
Animal Restless-urinary tract irritation
Sweating
Mucosal hemorrhage
Cardiovascular problems
GI problems-diarrhea
Neurological problems
Prevention
• Be able to identify beetles.
• Always know the source of where Alfalfa is
being grown and ask about the prevention of
beetles.
• Blister beetles usually appear in the warm
months of June-Sept. Harvest hay before
these months.
• Harvest hay before the blooming of flowers.
• Inspect hay before feeding.