Sunday, October 10, 2010

THE VAPOURER MOTH (DISPERSAL)

On October 5th 2009 I found a moth on the outside of my hall window to which it had been drawn by a light.On seeking to identify it I found it was a Vapourer moth ,a male easily diagnosed as the female has no wings,(yes no wings,it sits beside the cocoon from which it has emerged ,mates ,and lays eggs on the outside of the cocoon and dies).
On  24/09/2010 while walking I found the caterpillar of the Vapourer feeding on willow ,its very distictive and quite colourful.
I brought it home to show my children and when I went to release it the following day it had cocooned itself ,so I left it in its container,given its small size I thought it was likely to be a female as there was no way it could produce wings as big as the male.
Today 10/10/10 it hatched ,a small wingless insect ,woolly,swollen with eggs to be fertilised,its sole function to mate by attracting males using pherones.It will then die leaving the eggs to overwinter before hatching in batches from end of March on.

Given that the female can"t fly,the dispersal of the species is dependant on how far the caterpillar can travel from the pupating site,so it is quite local, and very dependent on its habitat not changing suddenly. Allowing for predation by birds etc it has a tough battle to survive without any environmental change.Another reason why we have to be careful in our environmental  actions.

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