Molecular simulation modelling of the circadian system of the blow fly, Lucilia cuprina

The Australian sheep blow fly, Lucilia cuprina, is a day active calliphorid whose larval stages are facultative parasites of sheep. As a calliphorid, L. cuprina provides an interesting comparative platform to examine the cons ervation of circadian timing mechanisms in the Diptera. Here we describe th e development of a quantitative dynamic simulation model for the circadian system of L. cuprina which is based on data concerning the molecular nature of the feedback loop in Drosophila and is modified to account for the basi c behavioural differences between Lucilia and Drosophila. The model provide s a representation of behavioural rhythmicity and the underlying molecular oscillations which generate this rhythmicity. Some of the basic molecular a ssumptions of the model have been supported by cloning a full length L. cup rina per cDNA and expression analysis of this gene (Warman et al., Genetica l Research Cambridge 75 (2000) 257). Having produced a biochemically valid model, its predictive power was tested. Simulations of the response of the circadian system to constant bright and constant dim light were validated a t a behavioural level and the model was used to predict the molecular chang es underlying these behavioural responses. The integration of molecular dat a with classical approaches to chronobiological modelling leads to improved insight into the functioning of dipteran circadian systems. (C) 2001 Elsev ier Science Ltd. All rights reserved.