Snail-killer

Today we finally got around to finishing off surveying the road verges that form the boundary to the Whitemoor Marshalling Yard. From there it was just a short trip to the Wildlife Trust reserve at Norwood Road, which Pete's surveying this year. He spent about 90 minutes catching insects, while I mooched round the site, photographing things that took my fancy, recording the flora and picking the first blackberries of the season.

I was particularly taken by this snail-killing fly, which was sitting on a reed stem and apparently licking it with its large spongy mouthparts. I'm not sure what value this had for it, as the adults normally sit on flowers and drink dew or nectar. The larvae are far meaner, as they prey on or become parasites of slugs and snails. Very little is known about the complete life cycle of these flies but most of the known larvae are semi-aquatic and some are aquatic. Other species have terrestrial larvae. Larvae mainly prey on non-operculate snails. Some species which prey on bivalves have larvae adapted to breathing under water. In some terrestrial species the penultimate larval instar emerges from the snail or slug it developed in. The last instar is then predatory on several snails.


After we'd completed our survey of Norwood Road, we had a walk around the nature reserve at Whitemoor Prison. It was quite surreal walking round watching dragonflies and damselflies darting among the reeds, and butterflies nectaring on the teasels, while less then 100m away men who had committed heinous crimes were incarcerated in their cells. One of the most surprising things we found on the reserve was a huge stand of cut-leaved teasel, thousands of plants mostly over 3m in height, like some alien army.


By the time we returned to the car I was feeling rather hot, not surprising when I found it was nearly 27C. We decided to have an impromptu barbecue to make the most of the summer evening, and were joined by a couple of friends. It was really special to be able to sit out in the garden as dusk fell, drinking and chatting, and listening in to the ultrasonic calls of the pipistrelles on our bat detector, without feeling chilly.