Dispersal and orientation of sterile Ceratitis capitata and Anastrepha ludens (Tephritidae) in Chiapas, Mexico.
The dispersal of marked, sterilized adults of Ceratitis capitata and Anastrepha ludens, which had been released on 6 occasions in coffee and mango plantations in Chiapas, Mexico, was studied using traps arranged regularly around the release points. The mean fly position moved significantly from the release point in all cases, generally towards the north and east (the direction of prevalent daily winds). On 23 of 37 experiment days, the pattern of trapped males was significantly different from a circular distribution. The orientation of the released populations sometimes changed markedly from day to day, and these translational and rotational movements appeared to be independent of each other. The flies also generally spread out over a greater area with respect to time, as determined by calculating the areas of successive standard ellipses for consecutive days after release. Males of A. ludens tended to spread out less rapidly than those of C. capitata after a combined release.