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Family Meloidae - Blister Beetles

Easy-to-shoot beetle - Nemognatha Green flower beetle - Lytta stygica Lytta sublaevis Beetle ID Request - Lytta aenea Epicauta alphonsei Horn - Epicauta alphonsii Epicauta pennsylvanica ? - Epicauta puncticollis Meloid? - Nemognatha nemorensis Red-necked Beetle on Wavy-Leaf Thistle - Epicauta atrata
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga
No Taxon (Series Cucujiformia)
Superfamily Tenebrionoidea
Family Meloidae (Blister Beetles)
Explanation of Names
Meloidae Gyllenhaal 1810
the name "blister beetles" refers to the ability of causing skin blisters if handled
ca. 410 spp. in 22 genera of 3 subfamilies in our area, ~3000 spp. in 120 genera of 4 subfamilies worldwide(1)(2)
Overview of our fauna
Family Meloidae
Subfamily Meloinae
Tribe Lyttini Lytta
Tribe Meloini Meloe
Incertae sedis Spastonyx
Subfamily Nemognathinae
3-70 mm(3), typically 10-20 mm
Medium to large beetles, typically elongated and rather cylindrical, often found on flowers, foliage.
Head broad, generally rectangular when viewed from above.
Pronotum cylindrical and narrower than both the head and base of elytra.
Elytra not flat, typically rolled over abdomen.
Body soft, somewhat leathery.
Antennae filiform (thread-like) or moniliform (beaded).
Tarsi 5-5-4; claw either toothed or lobed.
Blister beetles of e. US are generally dull in color; western ones often very colorful(4), apparently aposematic.
Key to New World genera in(5)
Short-winged forms
worldwide and across NA, with greatest diversity in arid/semiarid areas (sw. US)(1)
For larval food, most utilize the provisions and larvae of native ground nesting bees (esp. Megachilidae & Andrenidae); several genera (in our area, Epicauta & Linsleya) utilize grasshopper eggs (Acridoidea)(3).
Adults feed on leaves and flowers of several families of plants, particularly Asteraceae, Fabaceae, and Solanaceae(1) Practically all major and minor food and forage crops are attacked by meloids to a greater of lesser extent. (6)
Life Cycle
Life cycle is hypermetamorphic. Larvae are parasitoids. Eggs are laid in batches in soil near nests of hosts, sometimes in nest of bee host, or on stems, foliage, or flowers. Larvae undergo hypermetamorphosis--first instar larvae (usually called triungulins) are active, have well-developed legs and antennae. These typically search for hosts. Later instars tend to have reduced legs and be less active, having found hosts. There is a coarctate (pseudopupal) stage, which is usually how the larvae overwinter. Life cycle may be as short as 30 days, or as long as three years. It is typically one year, corresponding to that of host(1)(4)(7).
Triungulins of some meloids, e.g. in Meloe, aggregate and attract male bees with chemical signals (Saul-Gershenz & Millar 2006).

Larvae are parasitic of grasshopper eggs or in the nest of bees.(8)
Pressing, rubbing, or squashing blister beetles may cause them to exude hemolymph which contains the blistering compound cantharidin. Ingestion of blister beetles can be fatal. Eating blister beetles with hay may kill livestock. The three-striped blister beetle Epicauta occidentalis can especially be a problem for livestock as they get caught in with the alfalfa feed. Several other species in Epicauta and Meloe (M. laevis and M. niger) may be present in alfalfa as well. Cantharidin, commercially known as Spanish Fly, may be present in higher concentrations in some species of Epicauta than Meloe (Capinera et. al., 1985).
Males of some other beetles (notably, Pedilus and some Anthicidae) seek out blister beetles, climb onto them and lick off the exuded cantharidin. These other beetles, resistant to the toxic effects, use the agent to impress their females; the cantharidin is transferred to the female with the sperm packet during mating. The eggs the female lays are coated with cantharidin to protect them from predators. Some plant bugs (e.g. Aoplonema) are also attracted to meloid beetles. (based on Jim McClarin's comment)
See Also
In similar families, head is usually not wider than pronotum(4): Cantharidae have elytra flat, not rolled · Oedemeridae have no "neck" · Pyrochroidae have antennae serrate (saw-like) or pectinate (comb-like)
The other two families of beetles producing bee-parasitizing triungulin stages are Ripiphoridae and Cleridae.
Print References
Cohen, A. C. and J. D. Pinto. (1977). An evaluation of xeric adaptiveness of several species of blister beetles (Meloidae). Ann. Entomol. Soc. Am. 70: 741-749.
Internet References
Overview of FL fauna - Selander & Fasulo, 2010 [Cite:185010] - image gallery & info on world fauna (9)
Texas Meloidae - Mike Quinn, 2015
Works Cited
1.American Beetles, Volume II: Polyphaga: Scarabaeoidea through Curculionoidea
Arnett, R.H., Jr., M. C. Thomas, P. E. Skelley and J. H. Frank. (eds.). 2002. CRC Press LLC, Boca Raton, FL.
2.Order Coleoptera Linnaeus, 1758. In: Zhang Z.-Q. (ed.) Animal biodiversity: An outline of higher-level classification...
Ślipiński S.A., Leschen R.A.B., Lawrence J.F. 2011. Zootaxa 3148: 203–208.
3.Blister beetles (Coleoptera: Meloidae) of Wisconsin: distribution and ecology
Marschalek D.A. 2013. University of Wisconsin - Madison. PhD dissertation. viii+349 pp.
4.Peterson Field Guides: Beetles
Richard E. White. 1983. Houghton Mifflin Company.
5.The New World genera of Meloidae (Coleoptera): a key and synopsis
Pinto J.D., Bologna M.A. 1999. J. Nat. Hist. 33: 569-620.
6.The Meloidae (Coleoptera) of Texas
Dillon, Lawrence S. 1952. American Midland Naturalist, Vol. 48, No. 2:330-420.
7.Introduction to North American Beetles
Charles S. Papp. 1984. Entomography Pubns.
8.Eastern Forest Insects
Whiteford L. Baker. 1972. U.S. Department of Agriculture · Forest Service.