It's raining ... caterpillars

[derelict]

A fortnight ago in the evening the only sound you could hear in the woods in Richmond Park was the sound of the new oak leaves unfurling. This week the only sound you could hear was the sound of millions of caterpillars stripping the canopy with the pitter-patter of a rain of caterpillar poo coming down. Now the poo has been joined by the caterpillars themselves.

http://www.wildaboutbritain.co.uk/ar...=58690&cat=502

It doesn't bode well for this autumn's acorn crop...

[Bub-les]

good news for the blue-tits etc in the area though.
Barbara

[derelict]

Originally Posted by Bub-les

good news for the blue-tits etc in the area though.
Barbara

At present flock of blue tits could raise their young on the caterpillars from just one infested tree - sadly there just aren't the populations of small insectivorous birds to deal with the infestation - partly because the park is an island in an urban sea and partly due to the excessive numbers of grey squirrels and corvids within the park. So there may well be wholesale defoliation this summer - it's a long way to Lammas. Already some trees are pretty much bare and swathed in silk where the beasties have dropped off after finishing off one leaf and climbed back up again to find the next ... at night the sound of insect jaws chomping away is loud, like radio static. It reminds me of one of Selma Lagerof's Nils stories...

[derelict]

I've just been reminded about this by Rowan1789 posting a comment to



the caterpillars are (I think) the usual suspects in such circumstances

The Green Oak Tortrix (Tortrix viridana) - fat white ones (or rather one!)

and the Winter Moth (Operophtera brumata) all the rest

both these insects pull the same trick on the oak tree of laying eggs the previous year that hatch just in time for the new leaves to unfurl. As this is something of a movable feast (in terms of timing) it is thought that genetic encoding lies underneath this and that this gives rise a 12 year cyclicity. If so I'm rather hoping this was the peak... certainly wouldn't want another of those next year.

The caterpillars strip the leaves they are on and then drop off onto the ground and climb up the tree in search of fresh foliage. The result is sheets of silk on the trunks of badly infested trees.

Some other trees were atracked including ?beech and horse chestnut though for the latter this paled into insignificance against the leaf miner infestation in June

For what its worth there were clouds of T. viridana flying on the evening
of June 8th