EARLY spring butterflies including brimstone and orange tip were busy feeding under the nodding flowers of bluebells, one of my favourite sights in woodlands in April.
Now it is time for the dainty holly blue (male pictured) a familiar butterfly of leafy gardens. On the wing from mid-April through May, there are two generations each year, the second emerging in late summer into September. A rather enigmatic species, the holly blue is common some years, as this year, but relatively scarce in other seasons.
This is probably as a result of a parasitic wasp which punctures the bodies of young caterpillars and lays eggs in them, the parasite eating their hosts alive as they grow, finally emerging after the caterpillars have pupated then died.
Unique among British butterflies, eggs are laid on different food plants at different times of the year, with the buds of holly chosen in the spring and ivy in late summer. In the absence of these plants, eggs can also be laid on dogwood, gorse or pyracantha.
Although holly blues are often seen in gardens they also frequent hedgerows and woodland margins.