Coitus interruptus or coitus disturbus?!

I came across a pair of large skippers (Ochlodes sylvanus) joined in copula. The female usually carries the male in skippers, as shown below. The female is on top, basking in the sunshine, whilst the male remains hanging below her. They can fly like this, but only slowly and deliberately: vulnerable to predators.

The large skipper (Ochlodes sylvanus) mating pair. Galicia, Spain

Copulation times are usually fairly short in small butterflies like hesperiids. I do not know how long this pair had remained in copula before I chanced upon them. Copulation durations in the North American fiery skipper, a similar sized butterfly, lasted from 4 to 72 minutes. I would have thought that 20 to 30 minutes would be typical durations for copulation in large skippers, but I do not know of any published records.

The large skipper (Ochlodes sylvanus) mating pair. Galicia, Spain

The male skipper forms the spermatophore inside the female – it is not just a matter of transferring a package – and the fertilizing sperms only migrate across during the latter stages of copulation.

So, I don’t suppose this pair took kindly to being harassed by another butterfly! Quite why a butterfly of another species – a small pearl-bordered fritillary (Boloria selene) – was buzzing about them is difficult to say. Perhaps it was being territorial? Or wanted to perch on that particular flower? Or feed on the dandelion?

Anyway, the SPBF kept up the harassment, and I managed to get a few photographs of it flitting about the pair, as I lay in the grass next to them.

Mating pair of large skippers being harassed by a small pearl-bordered friillary.

It’s possible that I also played a role in disturbing the mating pair? But with a 150mm macro lens I was not that close. However, all the attention appeared to get too much for them and they started to separate.

The large skippers start to pull apart

It’s possible that the copulation had run it’s natural course, but I am inclined to think not. Harassment by other males (of the same species) usually prolonges the duration of copulation in butterflies. Such pairings can also be terminated prematurely (only by the male) but it is unusual. On balance I think the pair were disturbed, both by me and the SPBF, but hopefully they both went on to mate again in some secluded corner of a quiet meadow!

The male and female separate themselves

This sequence was taken on 4 June 2019, in Galicia, Spain.

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