Blister Beetle

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Blister Beetle
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• The family Meloidae, blister beetles, contains
  about 2500 species, divided among 80 genera and
  three subfamilies

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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.

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• 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
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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 CycleA 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
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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
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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.

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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

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• Cases of fatal poisonings of valuable horses in
  Florida, Oklahoma, Tennessee, and Texas by
  ingestion of blister beetles trapped in baled
  alfalfa hay