Friday, April 26, 2013

Professor Zavřel's midges

A few days ago Sammy made me a small emergence trap for insects out of a plastic food box with some nylon tights material tied over the top.  This balances happily on Midsummer Pond, the principle being that insects emerging from the mud and water will fly up into the roof of the trap from where they can be collected for identification.

20130415 Metre pond trap I made my first emergence trap over fifty years ago when I floated a wooden, gauze-covered contraption out onto a Wealden pond at Robertsbridge and, within a few weeks, garnered an impressive number of non-biting midge species and other insects that had spent their early stages in the pond.

Today my new emergence trap contained two species: a dark-haired biting midge Forcipomyia sp. (Diptera: Ceratopogonidae) and the non-biting midge Zavrelimyia barbatipes (Diptera: Chironomidae).  The Zavrelimyia has carnivorous larvae whose prey is very small organisms in the water.  I have found adults several times in our area, usually associated with stagnant ponds.  However, other records are from streams and cold lakes.  This raises the possibility that there are two or more very similar species with the Z. barbatipes name - only DNA could tell.

The adult midges are pretty little insects with dark-banded wings and, in the males, translucent bodies marked the black and brown.


The genus Zavrelimyia is named after Jan Zavřel who was born in Třebíč, now in the Czech Republic, and who as a university professor did much research work on the Chironomidae and many other things.