Wood White Butterfly
One of the United Kingdoms most rapidly declining Butterflies. Numbers have
severely decreased in many areas of Britain since 1950, most markedly in the northern and eastern counties of England where the species is now very close to extinct. It is also becoming far more restricted in its remaining southern strongholds, with only around three colonies remaining in Somerset. The main threat stems from inappropriate woodland management which produces too much shade. Wood White is also a poor colonizer of new sites, so isolation of sites can cause local extinctions.
Distinguishable from other “whites” by its rounded forewing tips when resting, this dainty butterfly has one of the slowest and most delicate flights of all the British Butterflies. Males are distinguishable from females in flight by the intensity of a black spot on the forewing, which is greatly reduced in females. This is the smallest of the “whites”.
The preferred habitat for this species is woodland rides and margins, however they are occasionally found in meadows and other more open areas. Warm, damp, sheltered sites with abundant food sources for both larvae and adult are favoured. The larvae feed on plants in the pea family. Males can be seen “puddling” after rain, when they replace depleted minerals and salts from ground puddles.
This butterfly has a fascinating courtship routine involving an interesting display by the male. (Follow this link to see the Wood white butterfly courtship display http://www.butterfly-conservation.org/text/1563/courtship_in_the_wood_white.html).
The first brood, flying from the end of May to the end of July, is the main generation. There is also a partial second brood in late July and August across much of England. Eggs are laid singly on upper parts of the foodplant in sheltered, lightly shaded situations. The green, well camouflaged larvae tend to feed on the younger more nutritious growth at the top of foodplants. They pupate over the winter in the surrounding grassland.
In the Blackdown Hills AONB, Butterfly Conservation and the Forestry Commission are working to recreate landscapes suitable for the Wood White in an attempt to aid its recovery.
The Wood White Butterfly has a Somerset Species Action Plan (Wood White SAP) and is on the UK BAP Priority Species List.
Wood White photo credit C. Hancock