Tuesday, 30 June 2015

Probably one of the most gruesome ways for a beetle to die.

I've spent a couple of days doing a bit of survey work on one of the Border Mires in North West Northumberland,  trapping beetles, bugs, flies and spiders.  A pretty good couple of days with a good smattering of beetles new to me, including the beautiful Carabus nitens and Agonum ericeti.  However there are plenty of pictures of these lads for you to peruse on the web, so this little blog is about something a hell of a lot more sinister.  In amongst the trapped collection of Pterostichus nigrita/rhaeticus ws this rather interesting find, a Gordian Worm or Horse Hair worm as they are now more commonly known.  These are exclusively invertebrate parasites. Their larvae enter the host and develop reaching several centimetres in length.  The beetle in this picture is about 10 mm, so it gives you a little idea of the length of the parasite.  The adult worms live in freshwater and hijack the nervous system of the insect in order that it might seek out a wet and watery place. The insect heads for the water, dies and the worm leaves its host.  Pretty impressive.  This one got it a little wrong drowning in a little propylene glycol pitfall trap sometime between the beginning of June and the 26th June when the traps were checked and hence did not fully have time to exit its host. 

Pterostichus with Horsehair worm.  Northumberland June 2015 

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