Posted by Cor Zonneveld on 13-07-2007 08:55
#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 08:58
Posted by Cor Zonneveld on 13-07-2007 08:56
#2
This photograph shows the location of the oviposition site, just below the birch tree.
Posted by Susan R Walter on 13-07-2007 13:41
#3
Cor
I wonder if there is enough dung in the soil, old and well integrated, but not discernible to the human eye. It seems like the sort of place where the cattle might have liked to stand around under the tree in the shade.
Posted by Cor Zonneveld on 13-07-2007 15:38
#4
I think cattle is excluded by fences from this part of the area. In support of this, there was no discernible evidence (like hair on bark) of cattle having sheltered there. Anyway, this female was not ovipositing in dung, but in soil! Even if it were soil fertilized by cow dung, my observation does not fit the picture described by Stubbs and Drake.