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Some small acalypterate flies like the
tiny yellow Chryomiid with green eyes,
Chryomyia flava, live on bird droppings.
Obviously these are the connoisseurs of
the excreta eaters.
Now apart from those flies whose larvae
actually consume the dung, there are, of
course, those that consume the consumers.
Many of the adult flies seen on the dung
will actually have predatory larvae who
will spend their larval stage seeking out
the dung feeders for their own sustenance.
Mention should be made here of a dung-
frequenting pupa that finds itself amongst
the dung almost by accident. This is the
pupa of the internal parasite Gasterophilus
which lives in the stomachs of horses as
a larva and is excreted at the end of its
larval development, and so finds itself
deposited unceremoniously from a height of
about three feet amongst a small heap of
manure. On emergence the adult Gastero-
philus leaves the dung never to return.
One could get the wrong idea about flies and
dung. In fact only about 5% of our flies
are associated with dung. So when you are
eating lunch and a fly arrives for it's share,
remember only one in twenty has dirty feet.
Deciding which one is the problem, so pop
them in a tube or box and send them along to
me at:-
12 Tring Gardens,
Harold Hill,
Romford,
RM3 9EP,
and I will let you know.