Thread subject: Diptera.info :: Asilus crabroniformis oviposition in absence of dung

Posted by Cor Zonneveld on 13-07-2007 07:55
#1

On June 8 I saw Asilus crabroniformis in De Hamert, N-Limburg, The Netherlands. De Hamert is a sandy area ner the river Meuse (river dunes), partly covered by coniferous wood, partly by heath. In the terrain big grazars are used as part of the management startegy, so cow dung is widely available.

Despite this, I saw a female Asilus ovipositing in a place where no dung was present! I'm quite sure the female was ovipositing: probing with the tip of the abdomen close to Rumex acetosella and Deschampsia flexuosa. The first photograph shows this. I saw the female moving twice, ovipositing at another spot.

Stubbs & Drake (British Soldierflies and their Allies) explicitly mention that oviposition takes place 'under the dry crust of old dung of cows, horses and rabits, and sometimes in adjacent soil.' (p. 208) But there was no dung present whatsoever! This was ovipositing close to the roots of a herb and a grass. Since cows are present in the area at large, and dung is widely available, this seems a deliberate choice of the female.

I guess the larvae may feed on insects that live in the roots of the herbs and grasses.

Edited by Cor Zonneveld on 13-07-2007 07:58