Estimation of dispersal distance of the soybean pod borer Leguminivora glycinivorella (Lepidoptera: Tortricidae) by mark–recapture experiments

Abstract

The dispersal distance of the adult soybean pod borer, Leguminivora glycinivorella (Matsumura) (Lepidoptera: Tortricidae), was clarified by conducting nine mark–recapture experiments. Seventy-one pheromone traps in 1 year and 80 in another were placed in a lattice pattern and adult borer moths were released from a central point. Captured male borer moths were counted daily for about 2 weeks. Data were fitted to a two-dimensional diffusion model and nine dispersal equations were estimated. We selected the optimum dispersal equation by comparing the number of naturally occurring males captured by the pheromone traps in the field with the number estimated by each equation. The quantile value of the diffusion curve was used to estimate the probability of insects settling at a location exceeding a certain distance from their source. The optimum equation estimated the lifetime natural mean dispersal distance to be 39.4 m. The estimate of the required isolation distance increased slightly with increasing density of adults in the source field. This distance was 352 m when we assumed the maximum possible density of adults that emerged in the source field and the sufficiently small density of entering adults (0.01 per 1 m of width) to avoid underestimation of the damage risk in the destination field. These results quantified the mobility of L. glycinivorella, which is very low.