Marsh fritillary

Distribution

Research work on the population dynamics of the marsh fritillary has shown that they live in metapopulations. A metapopulation is defined as a collection of local populations that are connected together as a result of occasional dispersal. Amongst these some will disappear and others will be founded.

Usually the marsh fritillary lives in small populations that tend to die out and new populations are founded from nearby sites. An important feature of metapopulations is that there will always be empty habitat within the system. It is possible for the majority of the habitat patches to be empty. The security of suitable places where the butterfly does not presently occur is essential to its survival in the long term.

Behavior

The eggs are laid in groups on the underside of the leaves in May and June. Up to 350 are laid in a single batch. They turn from pale yellow when first laid, turn bright yellow, then crimson, and finally to dark grey just prior to hatching. The caterpillars hatch from the end of June onwards. The young caterpillars live in communal webs that are spun across the foodplant and these become conspicuous by the end of August. In the autumn they make stronger webs, closer to the ground usually within a dense grass tussock, where they will start to hibernate. In the spring the caterpillars start to disperse from their communities after their last molt. They change colour from brown to black and may be occasionally seen basking in the sun. They need to be warm in order to eat. The caterpillars are liable to be attacked by the parasitoid wasp "Apanteles bignellii", especially in warm spring weather. Pupae form from mid April, low down deep within grass tussocks or dead leaves. Adults mainly emerge from mid-June to mid July, however in southern regions can be on wing starting from late May.

Habitat

* Damp and heathy grassland, dominated by tussock forming grasses, including Purple Moor and Rush Pastures
⤷  Calcareous grassland
⤷  Temporary colonies - woodland clearings and other grasses

Food

The main food plant of the marsh fritillary is the Devil's bit scabious, "Succisa pratensis", but can also include the field scabious "Knautia arvensis" and the small scabious "Scabiosa columbaria".