what are they doing?

[AWR1967]

Hi,
I spotted these little guys this afternoon.


What are they up to?
It looks like two Burnets helping a third one out of its cocoon. Can they really be that cooperative?

[dilettante]

I think it's just two mating, one freshly emerged from the pupa. The third black blob is just the remains of the pupal casing

[Susie]

The females don't even get a chance to get their wings dry before they're jumped!

[David M]

The females don't even get a chance to get their wings dry before they're jumped!

It's not as extreme as it seems. Females instinctively know that this is a good option in their short lives. That is why they're so receptive in this state.

[AWR1967]

Thanks, guys.
I always prefer to understand these things instead of just going "Ooh! Pretty!", especially as there are little people around here who're bound to expect me to know.

[Susie]

The females don't even get a chance to get their wings dry before they're jumped!

It's not as extreme as it seems. Females instinctively know that this is a good option in their short lives. That is why they're so receptive in this state.

Evolutionarily I would have thought it would be better if they could choose their mate rather than being unable to be lack of mobility.

[AWR1967]

People often assume all evolutionary advantages apply to all species. It's never that simple.
Moths and butterflies seem to use the same brute force approach to survival that fish use: make enough babies to overcome a massive mortality rate and give a few a chance of survival. There's no real advantage in choosing a mate under the circumstances because a stronger caterpillar isn't going to have any more survival chance if a bird fancies a snack. "The difference it would make (selecting a mate) wouldn't make a difference."
Contrariwise, random mating throws up more variations across the whole range of traits the offspring may differ by, instead of selecting for just one. Such random opportunity for mutation is more likely to throw up some new and useful trait such as a better colour match to an introduced (non-native) variant of a preferred food plant. That better colour match (better camoflage) results in higher survival rate and, consequently, more breeding opportunity. Result.

[Pagurus]

Thanks, guys.
I always prefer to understand these things instead of just going "Ooh! Pretty!", especially as there are little people around here who're bound to expect me to know.

Congratulations on what looks to me like a pretty unique photo. It's one that I'll remember

(I'm like you. I need to understand why things happen, which can be very frustrating. Spent days trying to find some decent books on invertebrate behaviour and only found one.)

À la perchoine

Pagurus (f)