Caterpillar Mites

[Cheryl]

I saw a number of Fox Moth caterpillars today and several of them had what looked like mites on them.



Does anyone know what they are and will it harm the caterpillar?

[Dogghound]

They look like ichneumon wasp eggs, a parasite of the caterpillar so they will cause it damage im afraid.

[Cheryl]

Oh dear But I suppose that's nature ....

[Jason Green]

Yes, as Dogghound says, an Ichneumon strike. It laid them there deliberately so the poor creature can't remove them. They will kill it I imagine.

[Harry Eales]

Originally Posted by Dogghound

They look like ichneumon wasp eggs, a parasite of the caterpillar so they will cause it damage im afraid.

I'd say they were more likely the cocoons of a parasite rather than the ova.
Most parasites lay their eggs inside the larvae by injecting them under the skin with their ovipositor.

Harry

[Dogghound]

I have to disagree, cocoon's usually are found on a dead caterpillar and its usually covered in silk unlike this one. I know of alot of ichneumons that lay external ova especially on the more hairy larvae like this.

[Meta menardi]

Hey, bad for the Fox Moth, good for the Ichneumons. Fox Moth is not easy to love.

[Dogghound]

Also rethinking alot of ichneumon pupate within the crysalis when the caterpillar starts to pupate, especially smaller species.

[Harry Eales]

Originally Posted by Dogghound

I have to disagree, cocoon's usually are found on a dead caterpillar and its usually covered in silk unlike this one. I know of alot of ichneumons that lay external ova especially on the more hairy larvae like this.

I'm by no means convinced that these are ova or a parasite. At this time of year Fox Moth larvae are just about fully fed and are about to hibernate.

Assuming the larvae which is pictured is fully fed then those will be exceedingly large ova.

I've bred Fox Moths from larvae collected both in the Autumn and Spring, and have bred them almost annually over fifty years. The only parasitised specimens I came across suffered from the Tachanid parasite G. glossa. A very large Black fly the size of a large queen Bumblebee. Only one or two parasites of this size can be found in the large larvae of the Fox Moth. The ova of G. glossa are however, quite small and are laid much earlier in the year than September.

It's a risky proposition for any parasite to lay its ova on the hairs of it's prey species as the larvae could quite easily cast it's skin before the ova hatch.

If the original poster can find some of these larvae again and send two or three to me, I'll willingly take a much closer look.

Harry

[Cheryl]

Originally Posted by Harry Eales

If the original poster can find some of these larvae again and send two or three to me, I'll willingly take a much closer look.

Harry

I shall look out for them Harry