27 February 2010

Once again we apologize for the incidental loss of life

Empty land snail shells collected under the assumption that they are devoid of life forms—other than protists and bacteria, which are unavoidably expendable—upon returning home occasionally bring forth previously hidden occupants, sometimes with tragic results.

This morning, while examining a bag of clausiliid shells that I had collected in Istanbul in May 2007, I noticed a small, about 5 mm long, object covered with stiff hairs. It turned out to be another hapless snail shell dweller that had died in the shell bag while trying to find a way out.

DeadDrilid2

The hairs and the pair of cerci identify it as a larva or a larviform female of the beetle family Drilidae. Here is a closer look at it.

DeadDrilid1

The larvae of drilids are quite common predators of snails in Europe and elsewhere. After a larva consumes a snail, it pupates within the empty shell of its victim, a process that may take several weeks. That's why they appear in containers of otherwise empty shells sometimes many days after the collection.

This post had another example of a drilid from a bag of shells. A recent paper about the drilids of Turkey is Kundrata R., Bocak L. 2007. A revision of Euanoma and Pseudeuanoma (Coleoptera: Drilidae). Annales Zoologici, 57: 427-441 (abstract). This post was about isopods that came out of snail shells.

4 comments:

xoggoth said...

Even at this time of year it is amazing how insect or other life is everywhere. Digging a small trench to put electrics through to the wife's greenhouse yesterday and there were some sizeable larva in the leaf litter.

Kazimir Majorinc said...

If they eat snails, they're evil!
Some photographies of that bug:

http://nature-au-jardin.be/blog/index.php/page/2

Sandy said...

Arthropods don't have 'hair'. Call them setae.

Hair grows from follicles, setae are projections from the exoskeleton that do not grow.

AYDIN ÖRSTAN said...

Hmmm...Gullan & Cranston* wrote: "setae, also called hairs..."

Whose authority do I accept?

*The Insects, 3rd ed.