Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
click beetle - Denticollis denticornis

click beetle - Denticollis denticornis
Harvard, Worcester County, Massachusetts, USA
June 17, 2006

Marshall's book (1) says this is the only North American Denticollis species, and it's an exact match of his picture.

It's a perfect match for
Denticollis denticornis in Dillon but we can't find any images online :(

What's up with google?
The denticollis images in bugguide have been around a good long while and should have come up in a google image search.

Oh. They do if you just search genus name :-)

moved to genus page
I see Jim has one just like this in the guide. Thanks John and Jane.

Firefly mimic
Wow, that sure looks like a firefly--nifty.

Does mimicking a firefly give this beetle any advantage, or is it just a coincidence?

Lampyridae are extremely toxic. Eisner talks about this in For the Love of Insects (1), for instance. According to Eisner, he and his lab discoverd this about 1964 by feeding different insects to a captive Swainson's Thrush--the bird rejected them out of hand, or beak, so to speak. The toxic compounds were dubbed lucibufagins by Eisner's group, and they are steroids, similar to some toxins found in toads and also to cardiotoxic compounds found in plants (so-called cardenolides, such as oubain and digitalis). Eisner recounts that a captive Australian bearded dragon lizards were known to have died from eating just one Photinus.

Eisner's group also found that Photuris lacked the toxins unless they fed on Photinus--perhaps accounting for why Photuris females lure Photinus males with the flash response of a female Photuris. (Eisner calls these females femme fatales.)

A second Wow:-)
Yes, Patrick, I just learned a bit more from your very well-worded text! Thanks much!

That explains why there are so many beetles, and a couple of moths I've seen that mimic fireflies. If I ever get stuck out in the woods, and have to eat bugs, I now know to leave the fireflies alone:-)
Thanks for the great explanation Patrick.