Sunday, February 19, 2012

Winter's Zebra Assassins

If you live in Ohio, you would probably agree that this winter has been a strange one. In the southeast, we haven't gotten much snow (much to my own chagrin). While this stops me from sledding down the available hills on campus, the mild weather at least means that you're more likely to encounter insects than you would be under two feet of snow.

A few weeks ago, on January 27th, a friend brought me a nice little surprise:

This little dude clad in zebra stripes is the assassin bug known as Pselliopus barberi. This species, like other assassins, is predaceous (just check out that beak!) and this one overwinters as an adult, explaining why it was found in January. It's not too large, just about 14 millimeters, but it's quite striking.

There are two species in this genus that you're likely to encounter often in Ohio: P. barberi and P. cinctus. P. cinctus is slightly smaller, and is a duller orange color. Before getting this one, I hadn't bothered too much with identifying them to species because it can be subtle differences that distinguish them, but the easy way to go about it is this: P. barberi is larger, brighter, and doesn't usually have a dark spot on its anterior pronotal lobe. Another character: the back margin of the pronotum on P. barberi is straight, while P. cinctus has a bisinuate margin. Let's use some pictures to explain those terms.

Pselliopus barberi

The back of the pronotal margin is straight, that's pretty easy to see.

Pselliopus cinctus

Now you can see the difference and understand what bisinuate actually means (I wasn't sure at first myself): the back margin of P. cinctus looks slightly flared out. You can also see the dark spot.

I've seen both species and one of their nymphs: their orange color really makes them stand out. My yard seems to be a pretty good place for them, as I've found the nymph on Queen Anne's Lace (Daucus carota) and an adult P. cinctus prowling around on Smooth Sumac (Rhus glabra) near some leatherwing beetles.

Keep an eye out during the warmer days of winter and you might spot a few. I've been keeping mine alive on fruit flies and will set it free during Spring if it can stay alive until then--I have high hopes!

1 comment:

  1. Wish these guys made it into the Rocky Mountain region! Here is another good page for differentiating the two eastern N.A. species: