Saturday, 22 November 2014

Nature of Corsica 5: Assorted Insects

Dragonfly - possibly Sympetrum striolatum
Insect life we found in Corsica after the hot dry summer was at a lower ebb than I might have expected, but there was still much to be found when we went looking. I will do a separate post on the various butterflies, but in this post I will cover some of the more interesting insects we found.

Oedipoda caerulescens - yes there is one in this picture!
Grasshoppers were singing everywhere of course – this one was found perfectly camouflaged against the gravel it was sitting on. We identified it as Oedipoda caerulescens, the specific name refers to the bright blue hind wings which are very obvious when it flies. During the trip we also found O.germanica, a very similar species with red hind wings.

Ant lion trap
In loose soil at one site we found the typical conical traps of ant lions. These are the predatory larvae of various species of lacewings. In the photo you can just see the head of the larva sticking out of the substrate, waiting for a wandering ant to fall over the edge. When the first grains of dust fall down to the centre of the pit trap the larvae flicks more sand to knock the insect down in reach of its large jaws. Various ant lions occur in the UK as well, but they are commoner in the south and east of the country where dry soil suitable for their traps is easier to come by.

Mantis religiosa
The most iconic of Mediterranean insects is probably the praying mantis. The ones we saw were Mantis religiosa, one of the larger mantid species. It has a vast range, from much of Africa across to central Asia and India, as well as being introduced to much of the US, and has been divided into various subspecies (the ones we found were the nominate form).

Mutilla europaea
The most interesting insect I found was a female European Velvet Ant, Mutilla europaea. This species is also found in the UK, and despite its name is not actually and ant, but rather a kind of wasp. Only the females are flightless, with the males having proper wings and flying well. Like the vast majority of the world’s Hymenoptera, they are parisitoids of other insects, in this case of Bumble bees Bombus spp. The female enters the bees nest and lays an egg in a cell containing a developing larva or pupa. The wasp larva feeds on this, and probably the pollen and honey the cell is provisioned with, before spinning its own cocoon in the cell. How big a wasp eventually emerges depends on how big a food supply it has – they sometimes enter honey bee hives and these result in smaller wasps eventually appearing. The female overwinters as an adult, often inside the old bee nest.
(Pictures are all mine)

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