Saturday, 3 September 2016

Up in the limes

A survey with a difference last week - Rob Bacon (NRW) and I spent two days in the basket of a cherry picker beating lime trees for caterpillars of Scarce Hook-tip. We last tried this in 2014 and had just three larvae in two days at St Pierre's Wood. This time we tried Barnets Wood, where there is good access to several mature Small-leaved Lime trees from the forestry tracks.

The cherry picker allowed us to reach the dizzy heights of 18m above ground. In theory the machine would allow us a little higher but it was a little un-nerving at anything over 15m, with the basket swaying as we moved about in it.
Cherry picker in action
At 3:50pm on day two we had recorded not a single Scarce Hook-tip larva and were feeling pretty downhearted. "Let's just do one more" we said to each other. And guess what plopped onto the beating tray! This was after 145 beatings of 6 mature lime trees.

Scarce Hook-tip larva, 14mm
The larva was 13.5m above ground, within the 13-17m range we recorded last time. Though not in the canopy (see red circle on photo below for approx. location) it adds some weight to the idea that this species breeds high on the trees. It's just a shame we didn't find any more, so we can't really claim this with any certainty.

We found plenty other species of interest: larvae of Pale Tussock, Red-necked Footman, Buff-tip, Lime Hawk, Roeslerstammia erxlebella, as well as the two Small-leaved Lime specialist micro-moths Salebriopsis albicilla (4 larvae) and Dichomeris ustalella (21 larvae).
Dichomeris ustalella
Red-necked Footman
And lots of other interesting insects including:
Pediopsis tiliae (a nationally scarce lime specialist leafhopper)
Longhorn beetle Pogonocherus hispidus
Nymph of the leafhopper Ledra aurita
All in all an interesting two days.  

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