Confusing black tailed skimmers?

[Ukwildlifeo]

I was in hainault country park by the big lake when I came across the normal balck tailed skimmers and too a few photos. When I got home I noticed this chap had yellow spots down the flanks of his abdomen. but he loos to skinny fro a broad bodied chaser, so I assumed it was a not quite fully mature male:



But then I looked at this mating pair and both are blue - I thought the female was yellow with black markings, like an immature male.





can anyone explain whats going on? lol

[Ukwildlifeo]

anyone?

[harasseddad]

They are BTS. The female has an upper abdomen pattern of yellow with black stripes (as has the immature male). Mature males develop a prunescence formed from a blue waxy substance they exude. This slowly covers the abdomen until it's entirely blue (apart from the black tail). So your first photo is of a male where the blue hasn't entirely covered the underlying pattern. The female in the other two shots is indeed yellow with black markings on her top - but you're seeing her underside here - which is black.