Identification of Factors Influencing Flight Performance of Field-Collected and Laboratory-Reared, Overwintered, and Nonoverwintered Cactus Moths Fed with Field-Collected Host Plants
Environmental conditions during egg and larval development may inßuence the dispersal ability of insect pests, thus requiring seasonal adjustment of control strategies. We studied the longest single ßight, total distance ßown, and the number of ßights initiated by wild Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) to determine whether the ßight performance of overwintered cactus moths with a prolonged feeding phase during development differs from nonoverwintered cactus moths. Pupae of
... ld-collected and laboratory-reared moths were transported together from the United States to Switzerland, and ßight mills were used to characterize the ßight capacity of 24to 48-h-old adults during their most active period of the diel cycle. The lack of seasonal variation in ßight performance of those moths that developed under controlled environment but were fed with Þeld-collected Opuntia cacti showed that seasonal changes in host plant quality did not affect ßight. This consistent ßight performance in the mass-reared laboratory population throughout the year is beneÞcial for sterile insect technique programs, which aim to limit the dispersal of this pest. For Þeld-collected C. cactorum, the larger overwintered females performed similarly to nonoverwintered females, indicating that longer feeding time at lower temperature increases body size but does not inßuence female ßight capacity. Young mated females had a similar ßight capacity to unmated ones, suggesting that gravid females may play an important role in invading new habitats. For males, overwintering increased the proportion of long-distance ßyers, suggesting that they are well-adapted to locate the more sparsely dispersed females in the spring.