I spent an enjoyable afternoon today at BBOWT’s Pavis, Black and Northill Woods nature reserve, where there was plenty of insect activity in the warm, humid conditions. This tree stump was at the edge of a path.
Old tree stumps are always worth investigating for insect life, and this one performed well! There was a small water-filled cavity in the top of the stump.
When I peered into it I saw a small forest of thin whitish ‘stems’. At first I thought they might be fungi, but some of them were moving, and I soon noticed that there were small whitish grubs at the lower end of each stem.
These are in fact one of the ‘rat-tailed maggots’, otherwise known as larvae of hoverflies in subfamily Eristalinae.
They seemed to be busy feeding – all the movement visible in the video clip at the top of this post comes from the hoverfly larvae, some of which are pushing and shoving at the bits of vegetation sunk under the water, all the while keeping their long rat-tails reaching to the surface to breathe air.
The most frequent species in tree holes is the Batman Hoverfly, Myathropa florea, but I can’t be certain that these larvae are of that species or one of its relatives.
Thanks to BBOWT for their work on this peaceful and life-filled reserve.