Friday, January 27, 2012

Friday Bug: Cosmopepla and Stachys

Two Twice-stabbed Stinkbugs do their thing on a bed of Hairy Hedgenettle
Bug blogging is fun, but also a chore that I find hard to keep near the top of the list of things to do. A major reason for that is my tendency for prolixity and another is that once I start a post I tend to get interested, dig deeper, and blather on. I guess those two reasons are actually one and the same and the solution obvious: a day with only short, simple posts. Here's a bug: isn't it pretty (not a question).
More 2-stab bugs with flowers
 So, here’s my new attempt to increase my productivity but reduce my prolixity: Friday Bug. First up is the Twice-Stabbed (i.e. two blood-red spots) Stinkbug now correctly known as Cosmopepla lintneriana Kirkaldy, 1909 (but with one of those long and complex nomenclatorial histories that I tend to run on about – short story: it was once Cimex carnifex Fabricius, 1798, then Pentatoma bimaculata Thomas,1865; and later and best , but wrongly, known as Cosmopepla bimaculata (Thomas, 1865)).
Twice-stabbed is a point of view
One of the interesting things about the Twice-Stabbed Stinkbug is that it seems to prefer to mix sex with flowers and so one has the opportunity to obtain colourful images. One can even find aggregations of butt-to-butt bugs on flowers; perhaps, as a result of males emitting a chemical scent that attracts females (and perhaps other competing males).
Bugs with purving crane fly
 Additionally, of course, stinkbugs are interesting because they stink. Krall et al. (1999) can tell you all about the chemical composition of the stink glands (aka metathoracic glands). More interestingly, they observed bugs have a good deal of control over their metathoracic glands and can shoot off one or the other or both if they so desire. Also, they nicely demonstrate that birds and a lizard are repulsed by bugs with full stink glands (but not with depleted glands).
Pasque flower seeds spark bug passion
Apparently, Ted MacRae’s cat likes to eat Twice-stabbed Stinkers, but in general, the bright black and red colouration and stink gland chemicals probably act as warning and revulsion to visually orienting vertebrate predators.
Yes, I smell and taste bad: Beware!
On a final fine note, the Twice-Stabbed Stinkbug has actually been studied in Alberta – and even better – the brief paper is now freely available.
Just hatched on a pea leaf - not a good sign
Only a few entomological journals are open access – Psyche and The Florida Entomologist come to mind. But the late, great Quaestiones Entomologicae has now joined these ranks thanks to the generosity of the many authors who have made their papers available under Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License and Kipling Will at the University of Califonria Berkeley who digitized the papers.
Twice-stabbed nymph in flower cluster
The Twice-Stabbed Stinkbug is a host generalist, but feeds almost entirely on seeds. So, finding them on your peas is not good, but on your garden flowers, not so bad. In Alberta, one preferred host is hedge nettle Stachys palustris. Well, that is what I thought anyway, but it isn’t only bug names that change. It seems former subspecies is now considered a distinct species by some: Stachys pilosa – Hairy Hedgenettle.
New & improved Stachys pilosa
In any case, except in New Jersey where a subspecies of S. pilosa is considered endangered, hedgenettle is doing fine and Twice-stabbed Stinkbug can’t be considered much of a pest. However, there is a crop species of hedgenettle – the Chinese Artichoke (aka Crosne, Chorogi) Stachys affinis.
Chinese Artichokes in Year III - a good crop for those who don't need to eat much
I’ve been trying to grow Chinese Artichoke for the last three years here in Alberta. The good news is that so far they have overwintered. The bad news is the tubers haven’t gotten very big (about half of marketable size) and the plants have never flowered. Our growing season is too short. On the other hand, no flowers = no seeds. So, Twice-stabbed Stinkbug will never be a pest and crosnes never a weed (they are naturalized in New York). Well, not a short and sweet post, but at least done and on Friday.
Crosne yield after 3 years (less nibbles)


McDonald JD. 1968.  The life history of Cosmopepla (Thomas) (Heteroptera: Pentatomidae) in Alberta  Quaestiones Entomologicae 4 (2): 35-38.

Krall BS; Bartelt RJ; Lewis CJ; et al. 1999. Chemical defense in the stink bug Cosmopepla bimaculata . Journal of Chemical Ecology 25 (11): 2477-2494   DOI: 10.1023/A:1020822107806


  1. McDonald asserts "widespread throughout North America and Mexico," but I can't recall ever seeing this thing - probably too fixated on beetles.

    Berlioz will eat anything!

  2. BugGuide has images from Washington, Iowa, Pennsylvannia, New York, New Hampshire, and Texas. I found a web page calling it the most common stinkbug outside Chicago

    Bev Wigney from Ontario - great stinkbug gallery - has it.

    Dave's Garden (no relation) reports it from:

    Deer, Arkansas; Cary, Illinois; Lombard, Illinois; Rock Falls, Illinois; Millbury, Massachusetts; Newfoundland and Labrador; Greensboro, North Carolina; Crossville, Tennessee; Pittman Center, Tennessee

    Other sites from Louisville, KY; Quebec, etc. But if you look at this distribution map, it does look like they are avoiding the southeast:

  3. I have often seen these bugts in the seed heads of of Pulsatilla spp. and wondered what they are doing there. I somehow never thought that the piercing mouthpars of true bugs would be very good at eating seeds -- I imagined juicier food sources where more likely.

  4. Yeah, used to think of bugs as predators and phloem/xylem feeders too, but many are seed predators. Even big ones like Western Conifer Seed Bug, Leptoglossus occidentals Heideman. Then so are a lot of smaller bugs, especially in the Lygaeoidea including my favourite family Rhyparochromidae - Dirt-colored Seed Bugs. A lot of carabid beetles eat seeds too. Then, of course, so do we.