Analysis of vertical distributions and effective flight layers of insects: three-dimensional simulation of flying insects and catch at trap heights.

The mean height and standard deviation (SD) of flight is estimated for over 100 insect species from their catches on several trap heights reported in the literature. The iterative equations for calculating mean height and SD are presented. The mean flight height for 95% of the studies varied from 0.17 to 5.40 m, and the SD from 0.12 to 3.83 m. The relationship between SD and mean flight height (X) was SD = 0.711X(-0.7849), n = 123, R(2) = 0.63. In addition, the vertical trap catches were fit to normal distributions and analyzed for skew and kurtosis. The SD was used to calculate an effective flight layer used in transforming the spherical effective attraction radius (EAR) of pheromone-baited traps into a circular EAR(c) for use in two-dimensional encounter rate models of mass trapping and mating disruption using semiochemicals. The EAR/EAR(c) also serves to reveal the attractive strength and efficacy of putative pheromone blends. To determine the reliability of mean flight height and SD calculations from field trapping data, simulations of flying insects in three dimensions (3D) were performed. The simulations used an algorithm that caused individuals to roam freely at random but such that the population distributed vertically according to a normal distribution of specified mean and SD. Within this 3D arena, spherical traps were placed at various heights to determine the effects on catch and SD. The results indicate that data from previous field studies, when analyzed by the iterative equations, should provide good estimates of the population mean height and SD of flight.