Sunday, August 1, 2010

New York City Flowerfall Event

You may or may not have noticed, but NYC is in the middle of a major flowerfall event—at least on some blocks! 
I pay attention to such things because two of my students have studied flowerfalls in the tropical rain forest. (Julie Feinstein reared over 1300 insects, including butterflies and moths, weevils, and many, many flies, from flowers shed by trees in the Brazil nut family; Amie Whigham is analyzing some of the factors that appear to make senescing flowers so appealing to insects).

The flowers currently filling our gutters are dropping from the Japanese pagoda tree (Styphnolobium japonicum). 

(Thanks to Carol Gracie, co-author of Wildflowers in the Field and Forest:
 A Field Guide to the Northeastern United States, for the identification-- 
I confuse this exotic with Robinia pseudoacacia until I see the fruits).
Both are common street trees in NYC.
Perhaps these dumpster-diving honeybees 
(Apis melliferaare seeking left-over nectar:
Pigeons and sparrows seem to like the flowers too:
If you follow insects at all, you are probably aware that honeybees are on the decline (if not, search for ‘colony collapse disorder’). I once got into a huge fight at a party because I steadfastly refused to tell a partygoer that I liked honeybees. While I concede that they are tremendously important pollinators of many food crops, in natural environments they can be considered non-native ‘pollen hogs’ that outcompete our native bees (we have more than 4000 native bee species in the US, and most are inconspicuous, solitary insects).  Colony collapse disorder? At the risk of irritating party-goers and colleagues alike, I would suggest that epidemics are simply the price that social animals pay.

For an amazing interpretation of social interactions amongst the honeybees, try to get ahold of Jim Self and Frank Moore's hard-to-find, but classic, East Village dance video, Beehive.

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.