The Holly Blue (Celastrina argiolus) is the first of the 'blues' to emerge in the UK. It is a regular sight flying along garden hedgerows during April and May and in good years, it can be seen flying from mid-March. It produces a second brood which is on the wing in July and August. The female of the spring brood lays her eggs under holly buds but females of the summer brood lay their eggs mainly on ivy buds, although I have also seen them laying on spindle and alder buckthorn.
On Tuesday afternoon, after a wet morning, I decided to watch for Holly Blues in my garden having seen good numbers flying through during the last week. After a while I noticed a male fluttering continually in the same spot on my holly hedge; behaviour suggesting that he had found a female, in fact a mating pair. I observed them for about 40 minutes before they separated naturally and the female settled low down in undergrowth to ripen her eggs.
Holly Blue (Celastrina argiolus) (mating; female on right)
Holly Blue (C.argiolus) (female)