Impact of flight on reproductive success of the navel orangeworm (Lepidoptera: Pyralidae)

The navel orangeworm Amyelois transitella(Lepidoptera: Pyralidae) is an economically important pest of fruits and nuts in California. Effective management requires an understanding of its capacity for spreading between orchards. On the day of eclosion, female moths were weighed and assigned to one of five mating/flight groups. Moths were placed individually in a glass jar with one or two males and allowed one night to mate. Each mated female was transferred to a jar containing a coffee filter and secured with a wire mesh lid. Eggs were collected and counted daily. With the exception of an untethered control group, moths were either affixed to a tether and attached to a flight mill or the moth was tethered but not flown. Preliminary data showed no correlation between distance or duration of flight and either fecundity or fertility but that handling and timing of moth flight versus mating did affect both. Moths that flew produced more and a greater proportion of fertile eggs than did the corresponding tethered controls. Moths that flew prior to mating were more productive than those that flew after mating. To investigate whether the observed effects are induced by the physical act of flying itself, moths are forced to fly for discrete amounts of time. The forced-flight trials also include males and determination of the male contribution to female reproductive output. This knowledge will lead to more effective management of dispersal and interpretation of pheromone trapping data.