Friday, September 7, 2012

Friday Stink Bugs: from the gaudy to the dowdy

Fall aggregation of stink bug nymphs
When I was a child, life was so much simpler. For example, a stink bug was a stink bug was a stink bug (although sometimes a stinkbug) and always Pentatomidae. 'Penta', of course means 'five', as in Pentagon, pentagram, etc., and 'tom' means 'cut'. Undoubtedly, this refers to the antennae of these bugs which are 'cut' into five segments. Most true bugs (Heteroptera) which get along with four or fewer. Alas, now we have two families to choose from: Pentatomidae and Acanthosomatidae. Well, whatever family they now inhabit, stink bugs usually live up to their names - they smell and, e.g. if one is too hasty eating a blackberry (not the electronic kind), taste bad too. Of course, many and possibly most 'true bugs' have thoracic glands that produce an odour that no one would mistake for a rose, but stink bugs are reliably smelly. Usually, though, they are not so brightly coloured.
Understated stinkyness - One-spotted Stink Bug
Take, for example, the One-spotted Stink Bug Euschistus variolarius (Palisot de Beauvois, 1805). Although not leaf green, as many stink bugs are, she clearly has no interesting in standing out. This is a full grown adult, but what I think is a nymph is similarly unremarkable.
What I think is a nymph larva of the One-spotted Stink Bug
Well, in my youth this was a nymph, as all immature terrestrial insects that did not go through complete metamorphosis were called. But now 'nymph' is out of fashion and hip entomologists call all immature insects, from maggots to hoppers, larvae. I'm sure the heuristic value of a holistic view of metamorphosis makes up for the loss of information conveyed by anachronisms like 'nymph'. Anyway, as long as someone knows that 'larvae' is plural and 'larva' singular, I'm unlikely to have a fit. (Although this information does not seem to be being passed down very well to the larval generation of entomologists.)
Twice-stabbed Stink Bug Adult and Larva: Cosmopepla lintneriana Kirkaldy, 1909 
Stink bugs are capable of advertising their distastefulness in both the adult and larval stage, as in the Twice-stabbed Stink Bug above. That our larval One-spotted Stink Bug does not is is interesting, in a rather intricately drab way. Why not advertise one's ability to make one go 'yuck!'? The One-spotted has a rather broad diet, everything from grass to veggies to fruit trees to other insects. So perhaps it finds being rather averagely drab an advantage in a variety of habitats. Sure, brightly coloured stink bugs may taste inexecrably bad, but who's to know until one tastes one?
Ground beetle that likes smelly food?
So is this predatory ground beetle (Carabidae) about to get the surprise of its life or does it like stinky food? Or perhaps caution will get the better of hunger. Alas, the photographer didn't stick around to find out, so we will have to end with a double mystery: and unknown larval bug and an unknown ground beetle.


  1. Thanks for helping me identify a stinker in Sask.!

  2. You are welcome. And the cluster of larvae at the top and bottom are of the burrowing bug (Cydnidae) Sehirus cinctus (Palisot, 1811).