Subject: RE: Ladybug invasion
Date: Oct 23 13:25:30 1998
From: Burton Guttman - guttmanb at elwha.evergreen.edu


On Fri, 23 Oct 1998 foxglove at jps.net wrote:

> I think the ladybugs are perhaps looking for a protected environment for
> winter hibernation.

They may be "looking for" a protected environment, and locally I've found
enormous numbers gathered at the partially open windows of our Lab
Building, sometimes getting inside. But the first time I encountered this
ladybug aggregation was long ago on the sandy shore of Lake Superior at
Duluth, and while they might keep one another warm and protected through
the winter by sheer mass and numbers, as bees do, they had found a
terribly cold, exposed place to do it. The insects secrete an aggregation
pheromone, which causes them to seek higher concentrations of the
pheromone, and so they may finally get together quite randomly, depending
on where a few nuclei form. I don't have any reference here that gives
any function for aggregation except the one I suggested--warmth by mass.
They surely can't be feeding in such massive numbers, and I wonder how
long they can stay alive, even assuming a very low metabolic rate because
of the temperature. I'd love to get more information.

Burt Guttman guttmanb at elwha.evergreen.edu
The Evergreen State College Voice: 360-866-6000, x. 6755
Olympia, WA 98505 FAX: 360-866-6794

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