As a student of woodboring beetles for more than a quarter-century now, I’ve had occasion to encounter a goodly number of checkered beetles (family Cleridae) – both in the field and as a result of rearing them from dead wood. Checkered beetles are not as commonly encountered as other woodboring beetle families such as Buprestidae and Cerambycidae, and they also generally lack the size, diversity, and popularity with coleopterists that those aforementioned beetle families enjoy. However, despite these shortcomings as a group, checkered beetles are among the most brightly colored and boldly patterned of beetles. Unlike the beetles with which they often found, checkered beetles are not actually themselves woodboring beetles, but rather predators of such (particularly bark beetles in the weevil subfamily Scolytinae).
This particular species, Enoclerus ichneumoneus, is one of the more conspicuous members of the family in eastern North America. Although the genus to which it belongs is the largest of the family (32 species in North America north of Mexico), the wide orange band across the middle of the elytra and elongate scutellum make this species distinctive and unlikely to be confused with any other. I found this individual along the Ozark Trail in southern Missouri on a recently fallen mockernut hickory (Carya alba) – a number of other adult buprestid and cerambycid species were also found on this tree, all of which were mating, searching for mates, or laying eggs within the cracks and fissures on this new-found resource. In the past I have encountered large numbers of adults of this species on dead willow (Salix caroliniana) from which I later reared an even larger number of a small willow-associated buprestid, Anthaxia viridicornis. Whether the buprestid larvae served as prey for E. ichneumoneus is difficult to say, but no other potential prey beetle species were reared from the wood.
The bright, distinctive colors exhibited by many checkered beetles might seem to suggest aposematic, or warning, coloration to discourage predation; however, the question of checkered beetle palatability to predators has not been adequately studied (Mawdsley 1994). The colors and patterns of many species, especially in the genus Enoclerus, seem to mimic species of velvet ants (family Mutillidae) and true ants, but other beetles (e.g. species of Chrysomelidae and Tenebrionidae) and even flies have also been suggested as models. Still other checkered beetle species seem to be more cryptically than mimetically marked, and there are several tribes whose members seem to be chiefly nocturnal and are thus mostly somber-colored.
Of the 37 genera occurring in North America north of Mexico, I have in my collection representatives of more than 100 species in 23 of those genera. The majority of that material has been reared from dead wood collected for rearing Buprestidae and Cerambycidae – much of it coming from Texas and Arizona as well as here in Missouri.
Photo Details: Canon 100mm macro lens on Canon 50D, ISO 100, 1/250 sec, f/14, MT-24EX flash 1/4 power w/ Sto-Fen diffusers, photo lightly cropped.
Mawdsley, J. R. 1994. Mimicry in Cleridae (Coleoptera). The Coleopterists Bulletin 48(2):115-125.
Copyright © Ted C. MacRae