Wiltshire and Swindon Biological Records Centre

Marsh Fritillary - Eurodryas aurinia

This is a fairly small fritillary that can mainly be found on the wing from late May to early July.

Marsh Fritillary, WWT/ Vicki Brown


Habitat

The Marsh Fritillary can be found on chalk grasslands where it feeds on Field Scabious and Small Scabious; but it can also be found in wetland meadows where it's main food plant is Devil's-bit Scabious. In all habitats an abundant supply Devil’s-bit Scabious – its main foodplant – is essential.

Description

Females are larger than the males but both sexes have distinctive orange and cream bands on its wings, each of the colours are outlined by dark brown which gives it an overall chequered effect. The hindwings have black spots on the orange bands and the underwings have the same pattern but much paler.

Biology

The main flight period is May to July, during this time the female lays large patches of eggs on the underside of leaves of the foodplant, the eggs are yellow in colour and turn red later. Only one brood is produced each year. Once the black and spiny caterpillars hatch they group together and form protective webs on the foodplants that are very visible towards the end of August. They hibernate over winter as larvae and the following spring, after emerging, the caterpillars disperse to complete their development. They pupate at the end of April and adults emerge about two weeks later.

Threats

Across Britain the Marsh Fritillary has undergone a massive population decline where over 60% of English populations known in 1990 had become extinct by 2000. In Wiltshire the Marsh Fritillary was widespread until its numbers started to decline and in a few years had become rare with a few scattered colonies remaining. The numbers of these colonies still seems to be declining. The drastic decline has been mainly due to habitat loss as the area of unimproved grassland has reduced as a result of the intensification of agriculture.

Grazing by cattle or ponies is the best management for the Marsh Fritillary; sheep grazing tends to be unsuitable as sheep eat Devil’s-bit Scabious and graze the sward too short.

The Marsh Fritillary populations are quite fragmented, but connected by dispersal over landscape areas, which causes additional problems as they need a network of suitable patches of habitat in an area to survive.

Conservation

The Marsh Fritillary is fully protected in the UK under the EC Habitats and Species Directive (Annexe II) and the Wildlife and Countryside Act, 1981. It is also a UK and Wiltshire BAP (Biodiversity Action Plan) species



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