Effect of temperature on Lucilia sericata (Diptera: Calliphoridae) development with special reference to the isomegalen- and isomorphen-diagram.

Developmental behavior of eggs, larva and pupa of the blowfly species Lucilia sericata (Meigen) were studied under 10 different temperature regimes. Data from these studies were used to construct the isomegalen-diagram. In this diagram, time from hatching to peakfeeding is plotted against temperature, each line representing identical larval length at various temperatures. If the temperature is roughly constant, as is the case with corpses found indoors, the age of the maggot can be read off instantly from its length, provided that the maggot has not entered the migratory phase. Where temperature is variable, an age range can be estimated between the points where the measured larval length cuts the graph at the maximum and minimum temperatures recorded. Equally, the isomorphen-diagram representing all morphological stages from oviposition to eclosion should be used, if maggots in the migratory phase or pupae or puparia are recovered from the scene. The isomegalen- and the isomorphen-diagrams could facilitate a quick and more precise estimate of the postmortem interval even for the inexperienced investigator. In addition, our results vary from those of other investigators, suggesting a different thermal behavior of the holarctic blowfly L. sericata in various zoogeographic regions.