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Family Meloidae - Blister Beetles
Classification Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga (Water, Rove, Scarab, Longhorn, Leaf and Snout Beetles)
Superfamily Tenebrionoidea (Fungus, Bark, Darkling and Blister Beetles)
Family Meloidae (Blister Beetles)
Other Common Names Oil Beetles Explanation of Names Author of family is Gyllenhaal, 1810. From genus Meloe (Linnaeus, 1758). The Century Dictionary (1) says etymology is uncertain, as does The Oxford English Dictionary, in its entry for Meloe. It dates first use to 1650, and gives early alternative spellings as Melaones (plural?) and, from a work by Paracelsus (1603) as melloes (genitive case). The OED states this may be related to the name Melolontha, a European scarab called the cockchafer. That genus name is from Greek μηλολονθη, apparently a name for the same scarab beetle.
The 1913 Webster's Unabridged Dictionary says Meloe is New Latin, from Greek, "to probe a wound". Direct link to an on-line version of the dictionary is here, and here is the text of the entry:
Meloe (page 910 of 1913 edition)
Mel"o*e (?), [ NL., fr. Gr. to probe a wound.] (Zoöl.) A genus of beetles without wings, but having short oval elytra; the oil beetles. These beetles are sometimes used instead of cantharides for raising blisters. See Oil beetle, under Oil. Numbers There are 22 genera and approximately 410 Nearctic species (2)
White (3) lists 26 genera and more than 335 species.
Worldwide, approximately 80 genera, 2500 species (Internet searches). Size 3-30 mm, typically 10-20 mm Identification Medium to large beetles, typically elongated and rather cylindrical, often found on flowers, foliage. Characteristics:
First abdominal sternite entire, not divided by hind coxae (suborder Polyphaga).
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 elongate, soft and somewhat leathery.
Antennae filiform (thread-like) or moniliform (beaded).
Tarsi 5-5-4; claw either toothed or lobed.
Blister beetles of eastern U.S. are generally dull in color, but western species are often every colorful. (3)Range Diversity is greatest in arid and semiarid regions, the Southwest (2) (3). Food Adult meloids feed on leaves and flowers of several families of plants, particularly Asteraceae, Fabaceae, and Solanaceae (2). Life Cycle Life cycle is hypermetamorphic. Larvae are parasitoids. Hosts include bees of families Megachilidae and Andrenidae. Epicauta (and other genera) larvae prey on eggs of grasshoppers. 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 (2) (3) (4).
In some cases, such as genus Meloe, triungulins aggregate and attract male bees with chemical signals (Saul-Gershenz and Millar, 2006). Remarks Pressing or rubbing adult blister beetles may cause them to exude some of their hemolymph (“blood”), which contains cantharidin. This compound causes blistering of the skin, thus the name blister beetle. See Also In similar families, head is usually not wider than pronotum (3):
Soldier Beetles - Cantharidae--elytra usually flat, not rolled
False Blister Beetles - Oedemeridae--have no "neck"
Fire-colored Beetles - Pyrochroidae--antennae saw-like (serrate) or comb-like (pectinate) Print References The Century Dictionary--entry for Meloe (1)
White, Field Guide to the Beetles (3)
Papp, Introduction to North American Beetles, pp. 100-105 (4)
Field Guide to Beetles of California (5)
Pinto, J.D. & M.A. Bologna. 1999. The New World genera of Meloidae (Coleoptera): a key and synopsis. J. Nat. Hist. 33:569-620.
Saul-Gershenz and Millar, 2006. Phoretic nest parasites use sexual deception to obtain transport to their host's nest. PNAS 103:14039-14044 ( abstract)
American Beetles, Vol. 2, Chapter 111 (2)Internet References
meloidae.com- World meloidae plus other beetle families
Works Cited | 5. | Field Guide to Beetles of California
By Arthur V. Evans and James N. Hogue | |
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