Population ecology and change in range of the white admiral butterfly Ladoga Camilla L. in England

Abstract

1. Ladoga Camilla L. underwent a striking expansion of range in the 1930s and early 1940s. The study was undertaken to investigate the reasons for this expansion.2. A life table study in Monks Wood, Cambridgeshire, analysed by the k factor method, showed the key factor to be late larval and pupal mortality. The mortality of these stages, believed to be due to bird predation, was dependent on the duration of the stages. At low temperatures the stages were prolonged and mortality high. Due to this relationship mean June temperature was closely correlated with adult numbers.3. Information from entomological journals from 1900 to 1977 was used to identify the timing of the expansion of range as precisely as possible. A good agreement was found between June temperatures over the period and the timing of the expansion.4. Although weather conditions determine year‐to‐year fluctuations it is likely that long‐term habitat changes also have an impact on L.camilla populations. The abandonment of traditional coppice management of woodland is considered to have increased the area of woodland suitable for the species and so played a role in its expansion.