The lesser of two jewels

Chrysobothris dentipes on exposed root of Pinus virginiana | South Cumberland State Park, Tennessee

Chrysobothris dentipes on exposed root of Pinus virginiana | South Cumberland State Park, Tennessee

A couple of months ago I wrote a post about Chrysobothris orono, a magnificent jewel beetle that I had the opportunity to see earlier in the year. Fellow buprestophile Joshua Basham and his colleague Nadeer Youssef had managed to find this very uncommonly encountered species breeding in exposed roots of Virginia pine (Pinus virginiana) on the edges of high bluff tops in South Cumberland State Park, Tennessee. I traveled to the site with them this past May and was rewarded with one specimen of the species, two Buprestis species that I’d not collected before (B. striata and B. salisburyensis), several photographs of each, and numerous memories. Chrysobothris orono was not, however, the only species in the genus seen that day. We also encountered numerous individuals of another species, Chrysobothris dentipes, on the same Virginia pines that were hosting C. orono, B. striata, and B. salisburyensis. Like C. orono, nearly all of the individuals seen were not on the trunks and branches of the pines, but on dead, exposed roots of the pines.

Presumed Chrysobothris dentipes adult emergence hole in exposed root of Virginia pine.

Presumed Chrysobothris dentipes adult emergence hole in exposed root of Virginia pine. Note pile of frass on the ground below the hole, suggesting that the adult emerged shortly before this photo was taken.

Unlike C. orono, however, which has only been recorded from a handful of states/provinces along the eastern seaboard and around the Great Lakes (and, now, Tennessee—MacRae & Basham 2013), C. dentipes is one of the widest ranging species in the genus, occurring throughout much of the U.S. & Canada and even the West Indies and northern Mexico (Fisher 1942). Throughout this expansive range, C. dentipes larvae develop in dead pine wood, although they have been reared also from tamarack (Larix laricina) and balsam fir (Abies balsamea) (Fisher 1942, Dearborn & Donahue 1993). I remember my excitement at collecting this species for the first time back in the 1980s in Missouri on log piles and slash from logging operations in the shortleaf pine (Pinus echinata) forests of southern Missouri. Eventually I realized how common and widespread a species it is, as it was the one species I could almost always count on seeing whenever I examined recently dead pines wherever I went.

The flattened body, dull coppery color, and partly yellow antennal segments make this a distinctive eastern U.S. species.

The flattened body and partly yellow antennal segments make this a distinctive species in the field.

The specific epithet (“denti-” meaning tooth, and “pes” meaning foot) apparently refers to the large spine on the front femora, although many species of Chrysobothris exhibit this character. This was one of the earliest described species in the genus, so perhaps other species with spined femora hadn’t been seen yet, or maybe the name refers to the toothed outer margin of the femoral spine rather than the spine itself. In any case, the species is rather distinctive and easy to identify in the field by its moderately large size, somewhat flattened body, and overall matte appearance. The clincher are the antennae, which may not be easy to see in the field but, unlike any but a few other very dissimilar species, have the outer segments partly brownish-yellow in color. Like most Chrysobothris species, adults are very “zippy” and alert in the field, the males running rapidly in short bursts when searching logs for females and both sexes quick to take flight when approached. While the adults in these photos are fairly conspicuous on the wood on which they are sitting, their coloration and surface sculpturing actually serve a cryptic function and make them very difficult to spot on rough pine bark where they are normally encountered.

REFERENCES:

Dearborn, R. G. & C. P. Donahue. 1993. An annotated list of insects collected and recorded by the Maine Forest Service, order Coleoptera, beetles. Maine Forest Service, Department of Conservation, Insect and Disease Division No. 32, 102 pp.

Fisher, W. S. 1928. A revision of the North American species of buprestid beetles belonging to the genus AgrilusU. S. National Museum 145, 347 pp.

MacRae, T. C. & J. P. Basham. 2013. Distributional, biological, and nomenclatural notes on Buprestidae (Coleoptera) occurring in the U.S. and Canada. The Pan-Pacific Entomologist 89(3):125–142 [pdf].

© Ted C. MacRae 2014

About Ted C. MacRae

Ted C. MacRae is a research entomologist by vocation and beetle taxonomist by avocation. Areas of expertise in the latter include worldwide jewel beetles (Buprestidae) and North American longhorned beetles (Cerambycidae). More recent work has focused on North American tiger beetles (Cicindelidae) and their distribution, ecology, and conservation.
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