Blister beetles are beetles of the family Meloidae, so called for their defensive secretion of a blistering agent, cantharidin. About 2,500 species are known worldwide.University of Florida, AskIFAS Blister Beetles (Insecta: Coleoptera: Meloidae) Many are conspicuous and some are aposematically colored, announcing their toxicity to would-be predators.
Description
Blister beetles are hypermetamorphic, going through several larval stages, the first of which is typically a mobile triungulin. The larvae are insectivorous, mainly attacking bees, though a few feed on grasshopper eggs. While sometimes considered parasitoids, in general, the meloid larva apparently consumes the immature host along with its provisions, and can often survive on the provisions alone; thus it is not an obligatory parasitoid, but rather a facultative parasitoid, or simply a kleptoparasite. The adults sometimes feed on flowers and leaves of plants of such diverse families as the Amaranthaceae, Asteraceae, Fabaceae, and Solanaceae.
Cantharidin, a poisonous chemical that causes blistering of the skin, is secreted as a defensive agent. It is used medically to remove warts and is collected for this purpose from species of the genera Mylabris and Lytta, especially Lytta vesicatoria, better known as "Spanish fly".
Toxicity Cantharidin from blister beetles has been used to create primarily aphrodisiacs but also poisons throughout history.
The largest genus, Epicauta, contains many species toxic to horses. A few beetles consumed in a single feeding of alfalfa hay may be lethal.University of Arizona VDL Blister Beetle Poisoning in Horses In semiarid areas of the western United States, modern harvesting techniques may contribute to cantharidin content in harvested forage. The practice of hay conditioning, crushing the stalks to promote drying, also crushes any beetles present and causes the release of cantharidin into the fodder. Blister beetles are attracted to alfalfa and weeds during bloom. Reducing weeds and timing harvests before and after bloom are sound management practices. Using equipment without hay conditioners may reduce beetle mortality and allow them to escape before baling.University of Colorado Extension Blister Beetles in Forage Crops
Evolutionary history The family is thought to have begun diversifying during the Early Cretaceous. The oldest fossil of the group is a larva (triangulin) found phoretic on a schizopterid bug from the mid Cretaceous Burmese amber, dated to around 99 million years ago.
Biology Blister beetles are known to attract bees with sex pheromones, then hitch a ride to their nests to dine on the bees' eggs. Ryan Alam of the Max Planck Institute for Chemical Ecology and colleagues analyzed the larvae of the European black oil beetle (Meloe proscarabaeus) --- they found a mix of molecules called monoterpenoids, rare in insects but common in flowers.
Systematics
Subfamily Eleticinae Tribe Derideini Anthicoxenus Deridea Iselma Iselmeletica Tribe Morphozonitini Ceriselma Morphozonitis Steniselma
Tribe Eleticini Eletica Tribe Spasticini Eospasta Protomeloe Spastica Xenospasta
Subfamily Meloinae
Tribe Cerocomini Anisarthrocera Cerocoma Diaphorocera Rhampholyssa Rhampholyssodes Tribe Epicautini Denierella Epicauta Linsleya Psalydolytta
Tribe Eupomphini Cordylospasta Cysteodemus Eupompha Megetra Phodaga Pleropasta Tegrodera
Tribe Lyttini Acrolytta Afrolytta Alosimus Berberomeloe Cabalia Dictyolytta Eolydus Epispasta Lagorina Lydomorphus Lydulus Lydus Lytta Lyttolydulus Lyttonyx Megalytta Muzimes Oenas Parameloe Paroenas Physomeloe Prionotolytta Prolytta Pseudosybaris Sybaris Teratolytta Tetraolytta Trichomeloe
Tribe Meloini Cyaneolytta Lyttomeloe Meloe Spastomeloe Spastonyx Tribe Mylabrini Actenodia
Ceroctis Croscherichia Hycleus Lydoceras Mimesthes Mylabris Paractenodia Pseudabris Semenovilia Xanthabris
Tribe Pyrotini Bokermannia Brasiliota Denierota Glaphyrolytta Lyttamorpha Picnoseus Pseudopyrota Pyrota Wagneronota Genera incertae sedis Australytta Calydus Gynapteryx Oreomeloe Pseudomeloe
Subfamily Nemognathinae
Tribe Horiini Cissites Horia Synhoria Tribe Nemognathini Cochliophorus Euzonitis Gnathium Gnathonemula Leptopalpus Megatrachelus Nemognatha Palaestra Palaestrida Pseudozonitis Rhyphonemognatha Stenodera Zonitis Zonitodema Zonitolytta Zonitomorpha Zonitoschema
Tribe Sitarini Allendeselazaria Apalus Ctenopus Glasunovia Nyadatus Sitaris Sitarobrachys Stenoria Genera incertae sedis Hornia Onyctenus Sitaromorpha Tricrania
Subfamily Tetraonycinae Tribe Tetraonycini Meloetyphlus Opiomeloe Tetraonyx
See also Blister beetle dermatitis Cantarella
References
External links
Blister Beetle Intoxication: Cantharidin Poisoning meloidae.com blister beetles UF / IFAS Featured Creatures striped blister beetle, Epicauta vittata UF / IFAS Featured Creatures Beetle mania as 'extinct' insect found on Scots isle Ever so Strange: Blister Beetles Mylabris Pustulata Orange Blister Beetle found in Farms near Nagpur, Maharashtra, India