Male Oil Beetle

2010 June 19

Back in October, I put up this post describing a female oil beetle, and mentioned that there seemed to be two very similar species, one that emerged as adults in the fall, and one that emerged in the spring. Well, here’s the one that emerges in the spring (S_ found it crawling slowly in front of the garage in the middle of May) , which is most likely Meloe angusticollis:

The one last fall was probably Meloe impressus. Aside from the time of year that it came out, this one also has little pock-marks on its back on the segment right behind the head, which I gather is an ID feature of M. angusticollis

When disturbed, the first thing they do is pull in their legs and lie there. I don’t know as I would call it “playing dead” so much, as daring you to eat them. I wouldn’t, by the way – they are filled with a blistering agent that would be very unpleasant to eat, and maybe even deadly if the predator was small enough.

I covered most of the highlights of these beetles in the posting last fall. The thing I really wanted to point out with this one, though, is the antennae. The females have straight antennae, but the males have a distinct crook in theirs about halfway up.

Evidently, a male uses the crook in his antennae for purposes of seduction. When he finds a female, he hooks his antennae around hers, and then runs them up and down her antennae. She evidently likes this, and it seems to get her in the mood to mate.

He may also use his grasp on her antennae to help hold on to her while they mate, but I’m not sure this part has actually been confirmed. The thing to keep in mind is that in insects, the antennae are basically the equivalent of our tongue, nose, fingertips, and maybe ears all rolled into one super-sensory organ. They are very, very sensitive. The antenna contact probably isn’t just tactile, either – the male is likely to be secreting chemicals that she can smell and taste. Antenna stroking is therefore probably more intense than it looks. A lot more intense.

One Response
  1. June 19, 2010

    Insect foreplay. Awesome.

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