Entomologia Hellenica 21 (2012): 13-24.

Benaki Phytopathological Institute, Department of Entomology and Agricultural Zoology, 8 Stefanou Delta, 145 61, Kifissia, Greece; e-mail: d.kontodimas@bpi.gr

Among several mathematical models used to describe the development or the fecundity of insects the equations of Enkegaard, Analytis, Bieri 1 and Bieri 2 could describe both biological features. In the current study these equations used to describe the development and fecundity of two pseudococcid predators [Nephus includens(Kirsch) and Nephus bisignatus (Boheman) (Coleoptera: Coccinellidae)] preying on Planococcus citri (Risso) (Hemiptera: Pseudococcidae) at constant temperatures (15^oC - 35^oC). All models have goodness of fit to data especially for development [R²_adj, RSS and AIC ranged0.9908-0.9996, 0.0019-89.1752 (x10^-4), and (-75.43) – (-31.07) respectively]. Optimum temperature (T_opt) and upper threshold (T_max) were calculated accurately by all models (T_opt ranged 32.6-34.0^oC for N. includensand 30.0-30.6^oC for N. bisignatus and T_max ranged 35.0-38.8^oC for N. includensand 33.1-36.0^oC for N. bisignatus, respectively). Lower temperature threshold (T_min) was calculated accurately by Bieri-1 model (11.0 and 10.0^oC for N. includensand N. bisignatus respectively) whereas Analytis model underestimated it (8.0 and 4.9^oC). As far as fecundity is concerned the respective values were better fitted near the optimum temperature (25^oC) [R²_adj, RSS and AIC ranged 0.8246-0.9704, 9.2729-24.0736 and (-246.82) – (-115.34) respectively]. Conclusively, from the tested models the Bieri-1 equation was proved as the most appropriate for the reason that could estimate correctly all the requested parameters concerning the development (T_min, T_opt, T_max) as well as it could describe sufficiently the fecundity trend of the two predators.