[Pollinator] Fwd: Xylocopa glob pics

[Peter Bernhardt]

Our lab has been studying the pollination biology of swamp milkweed
(Asclepias incarnata) at the Shaw Nature Reserve (Missouri).  Yesterday
afternoon, I caught three insects visiting the flowers and two were female
carpenter bees, Xylocopa virginiana.  Before pinning a specimen I count the
number of milkweed pollinarium plugs (corpuscula) attached to their mouth
parts and legs.  Upon turning this specimen over I noticed these yellowish
globs on the thorax and the bases of the legs.  These yellow globs were
very hard and really cemented to the bee.  A sample was scraped off, broken
up with a pin and stained with Calberla's fluid.  As expected, it was
composed of compacted grains of pollen from several species.

Can someone tell me what went on here?  How did this bee accumulate these
hard lumps on the underside of its thorax?  Was it making a pollen loaf but
was rather sloppy about it?  Is hard pollen a known "building block" in
carpenter bee burrows?  I've caught dozens of these bees over the last five
years on two milkweed species but this is the first time I've ever seen
this sort of hardened mass.  Dr Camilo is thanked for his photos.


---------- Forwarded message ----------
From: Gerardo Camilo <camilogr at slu.edu>
Date: Tue, Aug 2, 2016 at 10:50 AM
Subject: Xylocopa glob pics
To: Peter Bernhardt <bernhap2 at slu.edu>




-- 
Gerardo R Camilo, Ph.D.
Assoc. Professor of Biology
Bioinformatics and Computational Biology
   & International Studies
Conservation Fellow, St. Louis Zoo
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