How to tell the sexes in a mating pair?

[horace2264]

Lately I have been running into mating pairs of butts. I find it difficult to tell the two sexes apart when the underside patterns of the two sexes are similar, as in the example of the common caerulean (see pic). I wonder the experts here can advise on how to the tell the sexes apart from a view of tail-ends of these two butts.

Horace

[Cigaritis wong]

Good take!:thumbsup: too bad the flare.

I'm just guessing here by looking at the way they are "conjoined":bsmile:

The left is the female.

[horace2264]

Thanks Wong for the ID of the sexes for the pair.

Horace

[Commander]

Interesting... haven't really studied them closely before. But I am inclined to concur with wong. In butterflies, the males usually have a set of claspers with which they use to hold the female whilst connected. It is usually the male's decision to let go and separate the union, when it's had enough. ;P

You should keep the magnified inset, Horace.

[horace2264]

I was thinking that the tail-ends of the two sexes (ovipositor and clasper) should be of some standardized shapes for us to identify.

Here is the magnified inset for the common caerulean pair.

Horace