Linear relationship between peak and season-long abundances in insects

Abstract

AbstractAn accurate quantitative relationship between key characteristics of an insect population, such as season-long and peak abundances, can be very useful in pest management programs. To the best of our knowledge, no such relationship yet has been established.Here we establish a predictive linear relationship between insect catch Mpw during the week of peak abundance, the length of seasonal flight period, F (number of weeks) and season-long cumulative catch (abundance) A =0.41 MpwF. The derivation of the equation is based on several general assumptions, and does not involve fitting to experimental data, which implies generality of the result. A quantitative criterion for the validity of the model is presented.The equation was tested using extensive data collected on captures of male gypsy moths Lymantria dispar (L.) (Lepidoptera: Erebidae) in pheromone-baited traps during 15 years.The model was also tested using trap catch data for two species of mosquitoes, Culex pipiens (L.) (Diptera: Culicidae) and Aedes albopictus (Skuse) (Diptera: Culicidae), in Gravid and BG-sentinel mosquito traps, respectively.The simple, parameter-free equation approximates experimental data points with relative error of 13% and R2 = 0.997, across all of the species tested.For gypsy moth, we also related season-long and weekly trap catches to the daily trap catches during peak flight.We describe several usage scenarios, in which the derived relationships are employed to help link results of small-scale field studies to the operational pest management programs.