Friday, 21 August 2009
Larval Life 21/08/2009
Aside from inspecting their genitalia, the only sure-fire means of separating Grey Dagger and Dark Dagger is in the larval stage. I found this Grey Dagger feeding on one of our birch saplings: If you look closely, you can see that the head capsule has broken away showing that this larva is in the early stages of moulting to the next instar (I'm guessing from second to third going by its size). Also on the same birch sapling are a fair few gallery mines of Apple Leaf Miner moths (which aside from Betula spp. obviously also feed on apple and all other rosaceous trees and bushes): A few days ago I found a small sawfly larva in my MV trap and thought nothing of it. A couple of days later I found what I thought was a very large ball of frass on the slab where I run the trap. In the neighbouring garden they have planted a very quick-growing sallow which overhangs the fence over the trapping site. I checked the sallow but saw nothing. Today I checked again and found a load of gregariously feeding sawfly larvae which I've identified as Nematus pavidus. No idea on the status of this species, but other internet images all refer to it feeding on Salix spp. They were all resting in this strange posture, and waved their back ends around frantically when threatened. Whilst these were interesting, they did not account for the large frass ball. Tonight whilst checking the traps I looked up and finally found the culprit - a huge Poplar Hawk-moth larva which I'll try and photograph tomorrow.