www.ukbutterflies.co.uk

I know this is a Chalkhill Blue but to my mind it appears to have a female type hindwing and a male type forewing on the underside. From what I recall the upperside appeared to be a completely normal male colouration.
Do male Chalkhill Blues have such brown undersides to the hindwing or is this some sort of intersex individual.

I welcome your thoughts

Thanks

Paul

Hi Paul,

I posed a similar question recently after I found a couple of Chalkhill males with quite different underside colours to my expected norm.
Here they are compared to a "normal" individual.
All were taken in the same location on the same day.

I reserve any judgement on the intersex question, but I recall that the answer I got from Felix at the time was that these were within the normal range of colour variation for this species. However I cannot find that particular thread at the moment.

Vince

Hi Vince

I've noticed some very pale through to dark individuals at a few sites. This one struck me as being more unusual as the hindwing colour appears to be very gingery brown as in most of the females I see. It could be an effect of the light but this still is actually a video grab and the colour stayed the same even when this individual turned in the light.

Cheers

Paul

Hi Paul,

Chalkhill Blues are famously variable in respect of the underside ground colour, ranging from pure white (ab. alba) to deep slate grey (ab. pulla), chocolate brown (ab. castanea), or ochre yellow (ab. fulvescens; not infrequent on Portland).

Your specimen can be referred to as ab. fuscescens, first described by JW Tutt as male specimens with forewing undersides grey with hindwing undersides distinctly tawny-brown. This description seems to match your specimen rather well.

Felix.

Excellent.

Once again many thanks Felix.

What books or websites, if there are any, would you recommend for determining what abs. are present in Britain. I find this subject extremely interesting and being a bit of a clepto I enjoy photographing and filming these abs.

Thanks again

Paul