Trichodes bibalteatus in Oklahoma

Among checkered beetles (family Cleridae), the genus Trichodes contains among the largest and most strikingly-colored species.  The 11 North American species of this predominantly Holarctic genus are primarily western in distribution, although two species (T. nuttalli and T. apivorus) do occur in the eastern U.S.  The individual in these photos was one of several I encountered feeding on the flowers of a yellow composite in the Gloss Mountains of northwestern Oklahoma during early July.  I take them to represent the species T. bibalteatus based on their close resemblance to the holotype of that species from the LeConte Collection in the Museum of Comparative Zoology at Harvard University.  While these photographs are admittedly far from perfect, they were about the best I could manage at the time considering the gusty post-storm winds that I encountered atop the mesa where these beetles were found (along with my continuing difficulty in achieving proper exposure with subjects on bright yellow flowers).

The striking colors of adult Trichodes and their frequent association with flowers for feeding and mating belies a more treacherous aspect of their life history.  While adults may serve as important pollinators of native plant species (Mawdsley 2004), they also lay their eggs on flowers.  The larvae that hatch from these eggs don’t eat the flower itself, but rather attach themselves to bees and wasps that visit the flower as they gather pollen for provisioning their own nests (Linsley & MacSwain 1943).  The larvae hitch a ride back to the hymenopteran’s nest, where they then prey on the developing brood and usurp pollen provisions for themselves.

Photo Details: Canon 50D w/ MP-E 65mm 1-5X macro lens (ISO 100, 1/250 sec, f/16), Canon MT-24EX flash (1/8 ratio) w/ Sto-Fen + GFPuffer diffusers. Typical post-processing (levels, minor cropping, unsharp mask).

REFERENCE:

Linsley, E. G. & J. W. MacSwain. 1943. Observations on the life history of Trichodes ornatus (Coleoptera, Cleridae), a larval predator in the nests of bees and wasps. Annals of the Entomological Society of America 36:589–601.

Mawdsley, J. R. 2004. Pollen transport by North American Trichodes Herbst (Coleoptera: Cleridae). Proceedings of the Entomological Society of Washington 106(1):199-201.

Copyright © Ted C. MacRae 2010

Pseudomethoca simillima – a model for Enoclerus ichneumoneus?

Pseudomethoca simillima (family Mutillidae) - the model?

Enoclerus ichneumoneus (family Cleridae) - the mimic?

Last week, I posted the above photograph of Enoclerus ichneumoneus (orange-banded checkered beetle) and mentioned its possibly mimetic appearance to velvet ants in the family Mutillidae (order Hymenoptera).  By some stroke of serendipity, I encountered a species of Mutillidae the very next day in Missouri’s southeastern lowlands that seems to be a good candidate for one of, if not the, model species that E. ichneumoneus might have evolved to resemble.  Several individuals were encountered as they zigzagged urgently on dry sand deposits along the Mississippi River (where I had hoped, unsuccessfully, to find another locality for our intergrade population of Cicindela scutellaris).  Comparison of the individual in the photo with specimens in my collection (all identified by mutillid expert Kevin Williams, Utah State University) suggests this is Pseudomethoca simillima, and the photo is also a good match with other photographs of the species at BugGuide.  One thing that bothers me with the idea of this being a model for E. ichneumoneus is that I have not seen P. methoca commonly in Missouri (I have only three specimens in my collection), while E. ichneumoneus is one of our most common clerids.  There is another mutillid species in Missouri – Dasymutilla quadriquttata – that also seems to have potential as a model for E. ichneumoneus and that I have encountered much more commonly in the state.  However, D. quadriguttata is somewhat larger than E. ichneumoneus.  At any rate, other than the statement by Mawdsley (1994) that E. ichneumoneus seems to mimic mutillids, I can’t find that any more specific information has been recorded about the possible model(s) for that species.

As a caveat, I shall add that this mutillid was the… most… uncooperative… insect… that I have ever tried to photograph!  They really never stop moving, so you have to track the moving insect through the lens and fire shots when you think you’ve got it centered and focused.  Most of the time you don’t!  Using the Canon 1-5X macro lens for this did not make things any easier.  I tracked this female for quite a while and fired off a number of shots, only to get this one that I thought was fairly decent (and still just missed the focus on the near side of the pronotum).

Speaking of mutillids, I simply must photograph my specimen of Dasymutilla gloriosa (sometimes called the thistledown velvet ant) – you will not believe it!

Photo Details:
Pseudomethoca simillima: Canon MP-E 65 mm 1-5X macro lens on Canon 50D, ISO 100, 1/250 sec, f/14, MT-24EX flash 1/8 power w/ Sto-Fen diffusers. Minimal cropping and post-processing.
Enoclerus ichneumoneus: Canon 100mm macro lens on Canon 50D, ISO 100, 1/250 sec, f/14, MT-24EX flash 1/4 power w/ Sto-Fen diffusers. Minimal cropping and post-processing.

REFERENCE:

Mawdsley, J. R. 1994. Mimicry in Cleridae (Coleoptera).  The Coleopterists Bulletin 48(2):115-125.

Copyright © Ted C. MacRae

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

Email to a friend

Orange-banded checkered beetle

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.

REFERENCE:

Mawdsley, J. R. 1994. Mimicry in Cleridae (Coleoptera).  The Coleopterists Bulletin 48(2):115-125.

Copyright © Ted C. MacRae

Add to FacebookAdd to DiggAdd to Del.icio.usAdd to StumbleuponAdd to RedditAdd to BlinklistAdd to TwitterAdd to TechnoratiAdd to Yahoo BuzzAdd to Newsvine

Email to a friend