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Rove Beetle - Drusilla canaliculata

Rove Beetle - Drusilla canaliculata
Lancaster, Worcester County, Massachusetts, USA
April 21, 2006
Size: 5.5mm
Is arching it's tail over it's head agressive behavior, and if so, is there any defensive chemicals in the tail?

Images of this individual: tag all
Rove Beetle - Drusilla canaliculata Rove Beetle - Drusilla canaliculata

Thanks Boris!
It looks like the beetle is aiming it's rear end in a striking position. That's good to know about thier behavior.
You've done great work in identifying all these Aleocharinae, and to get this to species is great!

Pardon, all these names . . .
Sorry Tom, yesterday I wrote you this is Astilbus . . . of course, it is, but nowadays the genus is called Drusilla. They are ant hunters and flightless (look at the very short elytra with shoulders rounded off).

Before going further into taxonomy, I´d like to answer your question: Yes, the defensive glands of Staphylinids are located in the tail! In the subtribe Myrmedoniina, to which Drusilla belongs, the defensive glands are especially developed and been used as offensive weapon: Ants are stunned by the vapours and easily overcome by the beetle in this way.

Nomina Nearctica lists but two species in North America: The European canaliculata Fabricius, 1787, and the domestic cavicollis Casey, 1906.
D.canaliculata in Europe is one of the most common, most characteristic ground Staphylinids and is occuring in almost every habitat type.
The late description date of cavicollis instantly made me think that it may not be present earlier - it seems unlikely that entomologists like LeConte should have overlooked it.
I just checked the case and found that cavicollis has indeed only recently been sunk into synonymy (Gusarov, V.I.(2003): Revision of some types of North American Aleocharines . . . / Zootaxa 353: 1-134).

So this species becomes the first Alecharinae fully named in bugguide!

regards, Boris

Moved from Aleocharinae.

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