Males are bright sky blue in colour with a fine black line to the edge of the wings and a white border. Females are brown in colour becoming blue towards the body, with orange crescents towards the edges of the wings. Both males and females have pale brown undersides with black spots and orange crescents (1). The caterpillar reaches 1.6 centimetres in length, has a dark green body with dark spines (3), and yellow bands along the back and sides (1).
This species has two broods a year, there are therefore two adult flight periods; between mid-May and mid-June and early august to mid-September. Eggs are laid singly on the undersides of leaflets on small horseshoe vetches growing amongst short turf. The larvae feed on the underside of leaves, leaving typical feeding damage of small pale discs. Both larvae and pupae are always attended by ants, which are attracted by 'honey glands'. The ants provide protection against predation and parasitism and may even bury larvae at night! The larval stage over-winters, and emerges the following spring to complete development. Pupation takes place in the soil (4).
Found across Europe, in Britain the Adonis blue is at the northern extreme of its range (4), and has always been restricted to the warmer dry calcareous grasslands of southern England. It has suffered a huge decline in the last 200 years, and has been lost from Cambridgeshire, Essex, Suffolk, the Cotswolds, and the Chilterns. The main strongholds are Dorset, Wiltshire, Sussex (4) and the Isle of Wight (2). Over the whole of Britain there has been a huge decline of over 90 percent in numbers of this species since 1950 (5).
Many areas of suitable grassland have been removed by agricultural intensification, other sites have become degraded following abandonment or a decline in grazing, which maintains the short sward required by this species. In many sites a short sward was maintained solely by rabbit grazing, but the introduction of myxomatosis in the 1950s and the subsequent crash in rabbit populations led to a loss of short sward grasslands and a decline in the Adonis blue. After 1981, as rabbit populations have recovered and conservation measures have been put into action, the Adonis blue has made a partial recovery in some areas (5).
Many important sites for the Adonis blue have been designated as nature reserves, other sites have been targeted by agri-environment schemes such as Countryside Stewardship and Environmentally Sensitive Areas (ESAs) which have paid farmers grants to restore or increase livestock grazing. Despite these promising steps, in many areas the Adonis blue is still dependent on rabbit grazing, which can be unpredictable, to maintain a suitable sward height. Some sites are too small and isolated to support viable populations; horseshoe vetch is a poor coloniser and has been lost entirely from some former sites where there has been scrub invasion. The Adonis blue is a priority species under the UK Biodiversity Action Plan (UK BAP)(5).
The UK Biodiversity Action Plan for this species is available at UK BAP.
These schemes allow the government to compensate farmers for using methods that benefit the environment. The two main initiatives in the UK are the Countryside Stewardship Scheme and Environmentally Sensitive Areas. Since October 2000 these have formed part of the England Rural Development Programme (EDRP), administered by DEFRA, the Department of Environment Food and Rural Affairs. See: <link>http://www.defra.gov.uk/erdp/erdphome.htm</link> for more on these initiatives.
Containing free calcium carbonate, chalky.
Stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
Of the stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
An interaction between species in which one organism derivesits food from, and lives in or on, another living organism at the host’s expense.
Stage in an insect's development when huge changes occur, which reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
The process of becoming a pupa, the stage of an insect's development, when huge changes occur that reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
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