Sunday, October 24, 2010

Ambush Bugs

The sky was ominous this afternoon, but the temperature was a very pleasant 66-degrees.  Other than the usual suspects (chickadees, Purple Finches and nuthatches), there wasn't much avian activity along the Lower Chippewa River State Trail. 

So I decided to take a close look at the few goldenrods still in flower.  They were a-buzz with insects.  I felt some of them before I got close - female mosquitoes, getting in their last licks before the snow flies.  I spotted a few paper wasps, and a pair of what appeared to be copulating bugs with forelegs that reminded me of praying mantis.

Ambush Bugs paired
I've seen them before, but haven't been able to get a photo that could help me with identification.  Determined to get one today, I plucked the couple off the goldenrod and held them in my hand for good look (and better photo).

Was it a male was riding on the back of a larger (and lighter colored) female?  I'd have to figure it out when I got home. 

Ambush Bug
An hour later, I found them on Plate 3 in the Peterson Insects Guide: abdomen wider toward the rear; antenna 4 segmented, last segment swollen:  ambush bugs.

Known for sitting camouflaged on flowers (usually yellow or white), they wait to ambush their prey - the other insects working the flowers:  bees, wasps, flies, bugs and lepidoptera.  These tiny bugs are reported to take arthropods 10 times their size.

How to they do it?  They grab their prey with their modified forelegs and then bite, injecting a chemical that first paralyzes them, then liquefies their insides.  

Next time I see an ambush bug on a flower, I'll look for the lifeless exoskeletons of their prey nearby - on the flower and on the ground below.

Were they mating?  Maybe not.   Male ambush bugs are known for hitching a ride on the female's back as he waits to share in her hunting success.  (When ambush bugs mate, the male is lateroventral, not ventral-dorsal.)

If the pair I photographed today copulate, the female will glue her eggs onto a nearby twig, where they will over-winter and hatch out in May.  

Are they dangerous to handle?  While some references say they don't bite people, others say they do.   Next time, I won't take any chances.  I'll be carrying a glove in my pocket.

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