Friday, September 06, 2013

Knapweed ichneumon wasp

2013-08-20 11.34.10I recently caught this ichneumon wasp laying eggs into larvae concealed inside the flower stems and upper stalks of knapweed, Centaurea nigra, in Emthree. 

The wasp draws its ovipositor from its sheath (the black sting-like projection to the rear of its abdomen) then curls it under its body to pierce the plant tissue with great delicacy and skill.  Somehow, of course, it is able to detect the presence of the larvae in which its own larvae will live, probably in this case picture-winged flies (Tephritidae).

Identifying an ichneumon such as this is difficult without catching it, and not easy even if one does.  What I will try to do in this instance is to collect some of the flower heads and stalks and see if I can breed out both parasitoid and hosts.

2013-08-20 11.35.55

Wednesday, September 04, 2013

A new harvestman

I found the harvestman Leiobunum rotundum perched halfway up the stem of the white marsh thistle in Emthree the other day.

2013-09-01 11.01.03 2013-09-01 10.59.26 Quite a widespread species in Britain but possibly declining.  I have seen it once before in our garden (1997).