Quickie well done: no evidence of physiological costs in the development race of Lucilia sericata necrophagous larvae

The present study focuses on trade-offs between the development rates and their life-history traits of feeding larvae. Indeed, quick growth is considered to be vital for necrophagous insects such as larvae because they are part of a rapidly changing ecosystem and at the mercy of many predators. However, excessively quick growth can have a negative effect on other life-history traits (e.g. survivorship and body size). The blowfly Lucilia sericata (Diptera: Calliphoridae) is used in the present study because this species is frequently found on carcasses in Central Europe and is a well-known experimental model in insect physiology and ecology. Individuals are reared from first instars to adults at two different constant temperatures (i.e. 15 and 28 degrees C) and under three different conditions: 100 Lucilia sericata (i.e. small monospecific condition), 250 L. sericata (i.e. large monospecific) or 125 L. sericata +125 Calliphora vicina (i.e. heterospecific). The development time, pupal and larval survival rate and pupal size are determined individually under each condition. Regarding size and development time, substantial variation is observed between the different growth conditions and within a larval group under the same conditions. However, no trade-offs between development rate and size or survival are detected. These results demonstrate that, under the range of developmental conditions tested in the present study, the quick development of L. sericata larvae does not affect their size or mortality. This developmental plasticity may explain the evolutionary success of this species, which is present in several ecosystems worldwide and dominates the fresh-carrion ecosystem.