Tuesday, July 20, 2010

There are a gazillion insect stories in the naked city; this is one...

Long, long ago…. I got rid of the tomatoes, and planted my community garden plot with milkweeds and goldenrods. I had decided to feed not myself, but the BEETLES. I especially hoped to attract two cerambycids: locust borers (Megacyllene robiniae), which mate on goldenrod but lay their eggs on locusts, and milkweed beetles (Tetraopes tetrophthalmus), which feed on--you guessed it--milkweeds.

During the next year or two, I actually saw the occasional locust borer.  But the milkweed took over within a few years, and while it attracted a number of other milkweed feeders, I had pretty much lost all hope of attracting Tetraopes tetrophthalmus... until just last week, 15 YEARS LATER, when one individual arrived! 

First I noticed some unusual feeding damage;
many of the leaves were missing their tips. 
Then Mary T. spotted the culprit... 
and  documented its presence with her Iphone.
Can you see it? The long antennae gave it away.
I hurried back the next morning, hoping to catch it feeding.
But T. tetropthalmus (so called because the upper lobes of its eyes 
are completely separated from the lower lobes) 
was NOT pleased to be disturbed, 
and flew off to take refuge amongst the rose prickles.
I returned to my milkweeds to check out the feeding damage 
more closely. After all, not just any insect can feed on milkweed, 
with its gooey latex and toxic cardiac glycosides...

It turns out that "Tetro," like numerous other insects that eat 
latex-producing plants,  avoids the mess by slicing right 
through the leaf midrib! This diverts the flow of latex, 
allowing the crafty engineer to feed with near-impunity. 
Look CLOSELY!