Field Notes: JBWR Beetles UPDATED

Photographs by N. Arnzen.

There are something like 350,000 described species of beetles, order Coleoptera, and presumably many more that are not described. I once read that there are more species of beetles than all other species of animals combined, which may not be right, but it does give you some sense of their dominance on the earth. Perhaps 25,000 beetle species are found in North America north of Mexico. In our nook of the continent, specifically at the Jamaica Bay Wildlife Refuge in Queens, on Sunday, our party nearly stepped on these two representatives of the mighty order.
Now, only dabblers, we were wondering why the wings, or elytra, didn’t cover the abdomen, a sure sign of a beetle. Initially, then, we didn’t think they were beetles. But what else could they be? Digging in the Peterson Field Guide to Beetles, we discovered that a couple of beetle families have short wings, and ant-like bodies (look at that head!), like these. But no guide can picture all the known species, and it’s hard to identify a moving critter, so we are not sure what these are. We’re currently thinking a type of rove beetle, family Staphylinidae, of which there are around 3100 species in North America. These glossy hexapods were about an inch long, with one a bit larger than the other, which makes them big for the family as represented in the Peterson. We left them to their work, which, because that included the slightly smaller one clambering over the slightly larger one, may have been reproductive. Opps, excuse us!

UPDATED thanks to blogger TGIQ at Fall to Climb: these are actually oil beetles, of the genus Meloe. According to the Bug Guide the genus is known to feed on native bee larva and other goodies found in ground bee nests. The kink in the antennae, seen in the first image, may help the male in courtship. Kinky indeed.

8 Responses to “Field Notes: JBWR Beetles UPDATED”

  1. 1 amy melson March 23, 2010 at 5:01 pm

    Were they really soap-stone blue black like that? What a freakin’ gorgeous color.

  2. 2 TGIQ March 23, 2010 at 5:06 pm

    Although rove beetle is a really good guess, you’ve got a lovely pair of oil beetles there (genus Meloe) from the family of Blister Beetles (Meloidae). When disturbed, they exude an oily subtance from their leg joints. Nice find!

    • 3 TGIQ March 23, 2010 at 5:10 pm

      I’ll add, too, that your first picture captures both a male and female…the smaller fellow up top is the male…the size and also the modified antennae (you’ll notice an odd kink in the middle of it) are the giveaways.

  3. 4 mthew March 23, 2010 at 5:08 pm

    Yes, that’s a pretty accurate representation of the color. They were freakin’ gorgeous all around. Not that I’d want one crawling up my nose.

  4. 5 mthew March 23, 2010 at 5:38 pm

    Thanks, TGIQ, I’ve updated the post based on your very helpful comments. So the little devils were up to some kinky nookie after all. We didn’t touch them, being hands-off amateur naturalists, so we didn’t get see any of the “oil,” which is probably for the best, family blisters and all.

  5. 7 Katie April 18, 2010 at 10:32 pm

    Awesome! Thanks TGIQ for the ID. I’ve been looking to ID a mystery beetle of my own from last year ( I’ll update my post later.

  1. 1 An Inordinate Fondness #3: Discovery Zone « Fall To Climb Trackback on April 18, 2010 at 8:57 am

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