Larval diapause duration and fat metabolism in three geographical strains of the blow fly, Calliphora vicina

Abstract

Diapausing larvae of the blow fly, Calliphora vicina, from three geographical strains exposed, as adults, to short days, were maintained under identical conditions (darkness, 11–12°C) and examined for changes in wet weight, dry weight, water and fat content during diapause development to the emergence of post-diapause adults. Larvae produced by flies originating from northern Finland (Nallikari, 65°N) showed a longer, more intense, diapause than those from localities further south (Edinburgh, Scotland, 55°N and Barga, Italy, 44°N), but all three strains showed similar rates of loss of the parameters measured. This was also the case for post-diapause adults, flies of the Barga strain with its relatively short diapause emerging with greater residual fat reserves than flies from the Edinburgh or Nallikari strains with their more protracted diapause. It was concluded that the rates of water and fat loss were functions of the conditions used for diapause larval maintenance (probably temperature) rather than the maternally programmed degree of diapause incidence, or of its ‘depth’ or ‘intensity’.