Worcestershire Record No. 26 April 2009 p. 30
Cybister lateralimarginalis (the peardrop) is a large dytiscid water beetle found in continental Europe and historically from a handful of sites in Essex early in the 19th Century. Speculation that this species may re-colonise Britain has been proven correct with the recent discovery of Cybister in Lancashire. It would be interesting to find out whether it occurs elsewhere in Britain, so newt surveyors and trappers, please take a closer look at any large dystiscids you may find.
Cybister is a little larger than the familiar great diving beetle, Dytiscus marginalis. However, it doesn´t have the pale border all the way around the pronotum - just around the lateral margins, and it is a smoother shape, and often with a beautiful green sheen. The back legs are very muscular and the beetle can move more rapidly than Dytiscus. Some useful photographs can be seen at www.microcosmos.nl/beet1gal.htm
Please send any records or photos to Professor Garth Foster, Balfour-Browne Club, latissimus@btinternet.com. Even records of "ordinary" Dytiscus would be appreciated so your efforts will be valued whatever the species. If you are just sending photographs, please send some of both the dorsal and the ventral sides as it is the upper part of the rear leg that provides the best characters.
Now and again people send in living beetles expecting them to be sent back. This is possible, but Garth cannot guarantee a good outcome if he is away for a week when the post arrives!
Yours sincerely,
John Baker
Widespread Amphibian and Reptile Project
ARG UK/The HCT
The Herpetological Conservation Trust,
655A Christchurch Road, Boscombe, Bournemouth, Dorset, BH1 4AP.
01986 872016, 07884 441521
www.arguk.org
www.herpconstrust.org.uk