Dryomyza anilis, pitfall traps and preservatives

Submitted by sifolinia on

I ran a pitfall trap in a Breconshire woodland in 2018 and have been gradually looking through the contents. Between 2018-07-11 and 2018-08-08 it caught, among the usual ground dwelling arthropods, two female Neuroctena anilis.

I'd have put one specimen down to chance, but two specimens makes me think that they were probably attracted to the trap. The trap was covered, so they would have had to crawl under the cover to enter it. Despite the cover, the trap did capture a shrew during this period, so it seems likely that this might have provided the lure, rather than the dead invertebrates preservative.

However, it's got me thinking about the preservative used (propylene glycol). This has less odour than other preservatives I've tried in the past, so it may have had less of a masking effect. I'm wondering whether others have similar experiences involving N. anilis or other species and the preservatives used.