Skip navigation
Previous Next


June 17, 2010

Each week, month or even day there is always an enquiry favourite


This month's most popular enquiry has to be the Ermine moth, we have had sooo many calls and photos about this very naughty caterpillar. As ever, insects get in to the media when they cause a nuisance, and this one is quite dramatic. As an entomologist, I am not too phased by this extroardinary behaviour, but, to the unitiated, it might well appear like somehting out of  a horror film, to arrive at your car to find this:


Or wake up one morning and find this in your back garden:


Or, like this farmer from Suffolk, never seen anything like it in 40 years of farming:

2010 yponomeuta in suffolk.JPG


The Ermine moths belong to a family called the Yponomeutidae of which there are approximately 75 species in the UK. They are a very difficult group to tell apart as some can be morphologically very similar. However, for the more common species, as with many insects, they give us a clue to what they are by where we find them.


The photo above shows Yponomeuta sp 'tents' on Hawthorn; The Orchard Ermine, Yponomeuta padella larvae (caterpillar) takes hawthorn as one of its food plants, so we could make an assumption without actually seeing the specimen in this case. In identification - detective work is all-important!


The question that everyone is asking (again, insects get us talking) is why? Why are they appearing now, in areas they have never been seen before, and in such vast numbers? Well, I guess this is open to conjecture.


The ermines are quite common, they can be found on the wing from July-August - but what has lead to this 'population explosion'? Well, it could be lack of parasitization by Ichneumonids, in conjunction with exceptionally favourable enviromnmental conditions; in nature the balance can tip, but it rights itself in the end.