A mating pair - but which species?

[millerd]

Despite mostly cloudy skies and occasional drizzle, I found both Small and Essex Skippers flying on my local patch today (as well as quite a few other species). I stopped to take a few shots here and there to try and ID some of them, and focused in on a male Small Skipper.

What I didn't notice immediately was that in the background there was also a mating pair.

When I finally spotted them, I assumed that as the other male was taking an interest, they were Small Skippers as well. However, looking at the images of the pairing at leisure, the butterfly on the left (which I assume is the male) seems to have the dark-underside antennae tips of an Essex Skipper, whereas the female butterfly on the right seems to have the orange-underside tips of a Small Skipper.

I appreciate that the lowish light levels don't make for crystal-clear photos, and as I didn't twig the difference at the time I didn't get any definitive shots (which annoyingly would have been easy as the pair weren't going anywhere in a hurry!).

The small area where this all took place has a mix of both species, which doesn't help. The question remains - are these Small, are they Essex, or is this an example of interspecific mating? Are there any other details discernable from these photos that would confirm the ID one way or another?

Any suggestions welcome...

Dave

[David Lazarus]

I will go with Essex Skipper. The evidence is not quite visible for either the sex brand on the male in the background or the undersides of the antennae. Slight guess work - the sex brand, although quite deep/thick seems parallel with the edge of the wing. His antennae seem compatible with the ends of an Essex. A little bit of bleeding into the veins. The colour of the undersides is not convincing either way for me. Whereas the undersides of the female are compatible with Essex, I think, and the shape of the ends of her antennae. However, I cannot see the undersides well enough to say definite Essex. I may be wrong but the orange/brown doesn’t seem to belong to the underside. Anyway, a real challenge because of the lack of all the evidence.

[Pete Eeles]

Hi Dave - just to throw more confusion into the mix, a study by Barry Henwood, documented in "A Small Skipper, Thymelicus sylvestnis (Poda) with Black Undersides of the Antennal Tips" and published in Atropos in 2014, gives an example of a Small Skipper that contradicts the ‘rule’. The picture provided of the specimen is below. Based on this, I'd suggest that you're looking at a pair of Small Skipper, not least because this is presumably more likely than an inter-species pairing.

Cheers,

- Pete

[David Lazarus]

For comparison, Dave, these are Essex Skipper in cop taken today at the local meadow:

Essex Skipper in cop
Meadgate Fields Open Space 05/07/2024

[David Lazarus]

After the information provided by Pete I have changed my mind - Small Skipper hahahahaha

it is one of the skippers

[Neil Freeman]

Hmmm!. For the past few years I have been seeing many Small skippers being called as Essex Skippers based on some very dubious views of antennae, many of which do not clearly show the underside or show a vague graduation of colour. Small Skippers will often show this graduated look that can appear to be black but in reality is a dark brown.
I have gradually come around to the personal view that if it is does not show a clearly defined 'dipped in black paint' look, then it is not Essex, that is just my own view and one that I feel comfortable with, others may have a different view.

The photo below shows an example from last year of the only look that I will now record as Essex Skipper, unless of course it is a male and I have a good view of the sex brand.

Cheers,

Neil

[bugboy]

I'd go with everyone else, Small Skippers. I've come to the same conclusion as Neil (we've no doubt seen many of the same posts as we've slapped our hands to our faces) unless it's a nice clean antennae with a very obvious black tip, it's a Small. I think the problem these days is people have stopped treating guide books as guides and started treating them as religious texts!

[millerd]

I think we have a consensus here: they are Small Skippers. With the other one (a definite Small) taking an interest in the pair, it is logical that the female would be, and given the potential variation described above it follows that the male of the pairing is Small as well. Occam's Razor - the simplest explanation is probably the best!

Thank you everyone for your input!

Cheers,

Dave

[bugboy]

You know what I was saying yesterday about unless it's got a nice clean antennae with an obvious black tip, it's a Small? Yea scratch that, I was talking rubbish, Durlston Country Park today

[David Lazarus]

You know what I was saying yesterday about unless it's got a nice clean antennae with an obvious black tip, it's a Small? Yea scratch that, I was talking rubbish, Durlston Country Park today

That is my experience here in Essex

[bugboy]

We've been doing it all wrong, it's the front of the nudum, not the underside tip. Facebook has spoken!

[Pete Eeles]

What on earth is a "nudum"?

Cheers,

- Pete

[Trev Sawyer]

According to the Butterflies of America Glossary of Buttefly Terms, Nudum means: The scaleless area on the tip of the antenna, especially in hesperiids, where scent detectors are common. See: https://butterfliesofamerica.com/glossary.htm

[David Lazarus]

it's the front of the nudum, not the underside tip…

The distal antennomeres?

Looks like in practice it is something that in the field is indistinguishable. I think knowing the scientific name and exact location of these coloured cells doesn’t really help to tell the difference between Essex & Small Skipper for me. Under a microscope it may be different but that is not something butterfly recorders carry out.

I wondered if the combination of identification features provides much better chances of distinguishing the two?

Obviously the challenge is predominantly the female, when the Small Skipper has the above feature provided by Pete - that is looking from the front, slightly below the antennael tip level and cannot see orange at the tip, when she also has similar features which we mostly would associate with the Essex, such as black edges bleeding into the veins.

Especially, which I mentioned in my latest PD post, at the end of the season when they are both worn and tatty.

I was actually wondering whether the distal antennomeres can also appear faded to the extent the ink black of the Essex Skipper can take on a dark brown at certain angles to the light?

Anyway, very difficult, and not something, I think, we can leave to a set of “rules” or whatever as also mentioned above.

Interesting topic - I wish I knew the answer so that I was 100% confident in my identification rather than making informed assumptions about what it probably is based on such things as density/percentage colony combination. Or does it matter because we are probably talking about one or two only in a colony of 30-50?

[millerd]

Goodness, this is a minefield! On the basis of distinguishing male butterflies, I have identified one or two bits of my local patch where I have only ever found one or the other. The trouble is that the vast majority of the area happily supports both species, and these days they both emerge at the same time (within a day or two anyway). Only five years back, the Smalls were a week at least ahead of the Essex. Behaviour is very similar, though I always feel the Smalls are more vigorous fliers and the Essex less so (making them easier to follow). Feelings are not facts, however!

Obviously, the two species are closely related and frequently coexist in numbers on various sites. Has there ever been any evidence of hybridisation?

Dave

[Jack Harrison]

Goodness, this is a minefield!

Not such a minefield as the Olympics when the they can't agree on the gender of some participants.

Jack

[Stevieb]

Goodness, this is a minefield!

Not such a minefield as the Olympics when the they can't agree on the gender of some participants.

Jack