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(29-01) Modelling growth, emergence and reproduction of Chironomidae : interest in ecotoxicology. Péry, Alexandre*,1, Mons, Raphael, Flammarion, Patrick, Sulmon, Vanessa1, Garric, Jeanne, 1 CEMAGREF 3b quai Chauveau, Lyon, France ABSTRACT- We present a mathematical model for growth, emergence and reproduction of the midge Chironomus riparius, which is an organism commonly used in sediment toxicity tests. The model is based on assumptions about both feeding behaviour and use of energy for chironomids. After experimental testing and parameterisation, we were able to link quantitatively daily feeding, growth curve, emergence times and number of eggs per clutch. We could also model successfully the influence of density on growth and reproduction. On the one hand, as this is a well known confounding factor in toxicity tests where effects on survival and on growth occur at the same time, this could help greatly the analysis of bioassays. On the other hand, this allows a translation from individual to population level where effects on the carrying capacity can be studied. We could also quantify the influence of natural sediment characteristics on demographic endpoints, which allows translation from toxicity tests to population in the field. This influence is lower than that of feeding level, but can not be neglected. Moreover, it is more a qualitative than a quantitative influence. Particle size distribution and C/N ratio have an effect on growth and emergence. Lipid content produces an increase of reproduction efficiency in comparison with artificial sediments. Key words: chironomidae, model, reproduction, growth |
