Friday, September 28, 2012

Friday Bug: Broad heads, thin necks, and ant mimics

Reaching for the sky, getting it in the neck
I don't suppose anyone ever asked General Sherman his opinion on good bugs, but he may very well have said that the only good bug he saw was dead. Then again, may be not. Entomophobia isn't universal or even all that common in people who are both observant and enjoy being out-of-doors. Few, except perhaps eccentric entomologists, are entomophiliacs, but even fewer are completely misentomonic. For example, seemingly everyone loves butterflies, and even it they have reservations about butterflies in general ( (e.g. if their cabbage was just eaten by green worms), few would be rash enough to cast aspersions on a Monarch.
Alydus eurinus Say 1825 meets well-camouflaged Crab Spider
Thomas Say was one of those eccentric entomologists who may have loved insects. He described more than 1400 species of them and, as both a Quaker and a resident in the New Harmony utopian experiment, one might expect him to have held a benevolent attitude even toward bugs. In any case, we can thank Thomas Say for today's unfortunate bug meal for a near perfectly camouflaged crab spider (probably a species of Xysticus): Alydus eurinus Say 1825, a member of the Alydidae or Broad-headed Bugs.
Ant-mimicing nymph of Broad-headed Bug (Alydidae)
We have three species of Broad-headed Bugs inhabiting our pasture. The late Alydus eurinus, its congener Alydus conspersus Montandon, 1893, and its more colourful relative Megalotomus quinquespinosus (Say, 1825) all belong to the subfamily Alydinae and so are probably feeding on the vetch, clover, and alfalfa. In any case, they are common and as nymphs (or larvae if you prefer) do their best to look like black ants.
Mystery alydid mimic of black ant
Unfortunately, I can only key them as adults, so the nymphs remain mysterious, but rather good mimics of ants (presumably the common Formica podzolica and its relatives). 
Megalotomus quinquespinosus (Say, 1825)
The "Broad-headed" aspect of these bugs is more or less visible in the picture above - the head is rather broad compared to the thorax, at least compared to most of their relatives in the Coreoidea. But I do think this 'common name' (possibly made-up by an entomologist) leaves something to be desired. It's nowhere as evocative as, for example, the Tarnished Plant Bug, which also seems to make a habit of getting bitten in the neck by crab spiders.
A Tarnished Plant Bug gets it in the neck from another Xysticus.

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