Ichneumons as indicators?

[Wild-Woman]

Would the presence of a fairly large amount of Ichneumon-say 1 per square metre, suggest that there is a good population of caterpillars, (albeit unseen) in the same area,ready to play host to the Ichneumon eggs?
I witnessed this last week over unmown grass on one of the sunniest days. Can the Ichneumons be used as indicators or is this just dispersal after hibernation?

Jules

[Fourwings]

Good question Jules, but I'm not sure I know the answer

It would seem logical to assume that a wealth of predators/parasites in an area would indicate good numbers of its prey/hosts otherwise why would they be there is such large numbers?
On the other hand it could simply have been that you were witnessing emergence on a warm sunny day.

My brain isn't awake yet but I'm thinking about it though

[Wild-Woman]

Originally Posted by Fourwings

Good question Jules, but I'm not sure I know the answer

It would seem logical to assume that a wealth of predators/parasites in an area would indicate good numbers of its prey/hosts otherwise why would they be there is such large numbers?
On the other hand it could simply have been that you were witnessing emergence on a warm sunny day.

My brain isn't awake yet but I'm thinking about it though

Thanks for your reply Steve. I'm hoping that having nagged my boss into not having the area mowed, may have contributed into the population of insects increasing somewhat.
I can't remember seeing the Ichs in such numbers last year and fingers crossed, may have had the desired effect on the butterflies.

[Paul mabbott]

I think it 'proves' that there were plenty of hosts last year. If the ichneumons were succesful then they may have killed off all the leps .....

Originally Posted by Wild-Woman

Would the presence of a fairly large amount of Ichneumon-say 1 per square metre, suggest that there is a good population of caterpillars, (albeit unseen) in the same area,ready to play host to the Ichneumon eggs?
I witnessed this last week over unmown grass on one of the sunniest days. Can the Ichneumons be used as indicators or is this just dispersal after hibernation?
Jules

[UB4 gardener]

personally i'm surprised any leps make it at all. last year on catmint i spent a bit of time watching the caterpillars of the Mint moth (pyrausta aurata) so many were taken by wasps and parasitised. one wasp even had the cheek to land on my hand where i had been holding a stem back and proceeded to consume its victim. fascinating to see the range of sizes the ichneumons come in.

Chris