Yellow caterpillars in old bees nest

[Pierre Zagatti]

Bill Grange wrote:

> I have just had a number of yellow caterpillars brought by an enquirer
> into the museum where I work. They were inhabiting a plant-pot which was
> previously colonised by bumble bees.  The caterpillars are about 1.8 cm
> in length, with well developed 'true legs' and four pairs of 'false-
> legs' or 'pro-legs' (so I assume they are moth, rather than sawfly). The
> segments are very distinct. The body coloration is a strong yellow, with
> a brown head - no other obvious markings. The most remarkable thing is
> that they have constructed a silken mass of extremely tough silk,
> consisting parallel-running cylindrical cells.

I don't remember very well, but I think the larvae I reared many years ago
were yellow. It was the bumblebee wax moth Aphomia sociella L.
(Pyralidae Galleriinae).
The larvae develop in bumblebee nests, fresh or old. Hymenopteran
commensalism
is uncommon in the tribe Thyrathabini, but is the rule in the Galleriini.
The larvae should reach the adult stage without special care,
but avoid an excess of humidity.
Amazingly, the sex pheromone of the adults is produced by
a larval symbiont living in guts, Aspergillus ochraceus.

I still have some pictures of the adults, if you are interested.
--
Pierre ZAGATTI
INRA Unite de Phytopharmacie et Mediateurs Chimiques
78026 Versailles Cedex
FRANCE
Tel: (33) 1 30 83 31 18
e-mail zagatti at versailles.inra.fr
http://www.jouy.inra.fr/papillon/