Midges in spiders' web
Posted by Paul Beuk on 22 November 2004 09:07:22
Aphidoletes aphidimyza: several specimens hanging on one thread (closer view). (Copyright: Troy Bartlett)
From Tony Irwin:
'Hanging from spiders webs is known in a number of families of nematocerous flies. In Britain, I have found Culicidae, Limoniidae, Tipulidae and Mycetophilidae all utilising spiders' webs for resting, particularly in caves and cellars. It is possible that it is safer to overwinter suspended from a spider's web, rather than resting on the wall of the cave. Spiders have a "lower threshold" prey size, anything below which they ignore. I suspect that Aphidoletes is under that threshold for many spiders, so they are relatively safe from the spiders, and certainly safe from most other insect predators.
Looking at the photographs, it appears that Aphidoletes has strikingly pale tarsi. This is a feature shared with Dolichopeza albipes, a European tipulid that lurks in shady places (where its larvae feed on liverworts). The pale tarsi may be associated with the habit of hanging on spiders' webs, providing a distraction for larger predators such as wrens which often feed from webs.'
Note from the editor:
Tony's text was composed after seeing another image of Aphidoletes hanging from spiders' web. In this image, the tarsi of the hanging midges appeared to be white, just as in the top image in this article. I suspect that the tarsi may be pale, but that the white appearence was largely cause by the use of flash light. The other pictures in this article show that other parts of the legs may appear white as well.
Aphidoletes aphidimyza: several specimens hanging on one thread. (Copyright: Troy Bartlett)
Aphidoletes aphidimyza: male hanging on a thread (close-up). (Copyright: Troy Bartlett)
Submitted by Paul Beuk on November 21 2004 - 17:17:54