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Garden butterflies
Posted by: Richard Jones, 30 April 2008, 11.51AM
That warm Saturday (April 26th) brought out the first butterflies of the year: holly blue, small tortoiseshell and speckled wood. They're all common garden species, but I always get a thrill when I see any of them.
The female holly blue was fluttering round the ivy leaves. It had probably just emerged from a chrysalis hidden somewhere inside the dense foliage, because this is the wrong foodplant for this time of year. This butterfly is unique in Britain in having two generations a year on two completely different foodplants. Butterflies in the spring emergence lay their eggs on holly and their caterpillars feed on the developing buds. When these insects reach adulthood in late-summer they lay their eggs on ivy flower buds. At least that is the received wisdom because according to many observers in cities (where ivy, holly and the butterflies have always been common), they are now switching their egg-laying preferences to include pyracantha and snowberry.
The small tortoiseshell is one of only four UK butterflies to overwinter as an adult - peacock, comma and brimstone are the others, although the red admiral might start qualifying if it continues to survive our warmer winters. Any of these insects ought to have a head start as soon as the weather warms up, so to see the first one flying so late in April just bears out the fact that it really has been very cool so far this year.
The speckled wood flew straight past the back door, up over the fence and away. Despite its name it is definitely a garden butterfly in this part of south-east London. But then, we are lucky to have lots of fairly large gardens down this way, and Dulwich is still the most wooded part of the metropolis. The caterpillars feed on grasses, particularly cock's-foot, Yorkshire fog and false brome, so some of the unkempt back gardens in the neighbourhood probably have breeding colonies.
Speckled woods are often difficult to sex at a distance, and small tortoiseshells are impossible, but there is a neat trick to tell males from females - almost without fail. When you see one resting in a patch of sunlight, on a leaf, or on the ground, lob a small pebble, about a metre over the top of it. If it's a male, it will guard its territory jealously and fly up to investigate the missile. If it's a female it will ignore the stone and continue sunning itself. So confrontational are the males that they will also flap up to investigate other butterflies, bumblebees, birds and even passing aeroplanes.
Comments
Jeff Goodley
01 May 2008, 09.16AM
Eileen Shaw
01 May 2008, 09.27PM
brooker.brenda
04 May 2008, 10.55AM
Karin Clarke
06 May 2008, 08.47AM
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