Mimicry on Kei Island

[indowings]

Hi everyone,

thought there might be some collectors out there interested in butterfly mimicry. There is a wonderful mimicry complex on Kei Island, Indonesia. Several species of Euploea and two Hypolimnas are in mimetic association on this small dual-island (Kei Kecil & Kei Bessar). Hope you enjoy seeing some examples of these species.

David.

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[wollastoni]

Thanks David.

One important thing about mimicry. It must been assessed on "live" specimens. Because some specimens that don't look the same in collection, look nearly exactly the same when flying.

Example Cethosia cyane and Danaus genutia. When I collected them on Koh PhiPhi, I had difficulty knowing which of them I caught until I checked my net.

[steve]

and they need to be flying together ....

[wollastoni]

Sure...

[Adam Cotton]

Dec 19, 2012 1:53:55 GMT -8 steve said:

and they need to be flying together ....

Not always, by any means. They need to fly in the same general area, but not necessarily at the same time. Often mimics actually emerge at a slightly different time to the models, often a few weeks later, just after the predators have learnt to avoid them. Also the mimics may occur at a different elevation, or slightly different habitat, but the predators that have learnt to avoid the colour pattern move around more than the butterflies do.

Also mimics often fly at different times of day to the models. For instance 'Chilasa' species generally fly in the middle of the day, whereas their Danaiine models fly in the morning and late afternoon, and spend the hot midday hiding in the shade.

Generally though the mimics occur in lower numbers than the models, and also spend a lot less time as adult butterflies. Usually distasteful species can live as adults for several months, and it is the older, weaker specimens which have already mated/laid their eggs that are often eaten by predators. Often old specimens from the previous generation are still flying about when the fresh specimens of the next generation emerge.

Adam.

[wollastoni]

Agree with Adam, but I think it's what steve wanted to say.

They need to have the same predator and thus to be in the same place.

[indowings]

Curious. I find it difficult to believe that the Hypolimnas are not benefiting from having lightened wing margins when they occur on the same island as distasteful Euploea species that also have lightened wing margins. I think it would be very unlikely that the are not mimics of these Euploea species.
I have seen Danaus chrysippus and female Hypolimnas misippus flying in the Northern Territory several times. They were never flying together and the misippus flew like a typical Hypolimnas, not Danaus (yet misippus it is a celebrated mimic)...

[steve]

Thank you Adam, well said and that was what I clumsily tried to say! Certainly Euploea batesi (which has a spotted form and a non-spotted form, the latter being dark brown with very pale margins) and Hypolymnas antilope fly together on Murray Island in Torres Strait and are difficult to distinguish on the wing.

[Adam Cotton]

Mimicry is effective on wing pattern alone, not just flight appearance.

For example (at least here in SE Asia) it is often easy to spot the mimics when they are feeding on flowers. The Danaiine models sit on the flowers with wings closed, whereas mimics spread their wings wide open clearly showing the mimetic pattern. It is easy to spot the rare Papilio castor mahadeva females among the Euploeas at flowers using this method, and there are many other examples of mimics behaving in this way when feeding at flowers.

Adam.

[downundermoths]

david... Nice photo and very interesting. I did start to collect similar specimens from the Kei Islands, but didn't carry it through apart from a nice small series of Euploea leucostictos. Now you have got me all twitchy again...
Barry

[indowings]

Hi Barry,
it's a real pity Euploea phaenarete doesn't occur on Kei Island (it would no doubt be spectacular). But given Kei is a young island and was never connected to mainland PNG, I guess it's not surprising phaenarete isn't there...