Factors Influencing Flight Ability of Male Adults of the Diamondback Moth, Plutella xylostella, with Special Reference to Temperature Conditions during the Larval Stage

Abstract

Effects of temperature, photoperiod conditions during the larval stage and parental body size on flight ability of the male adult were investigated in the diamondback moth, Plutella xylostella, using a flight mill device. Larvae reared at a lower temperature developed into larger adult moths with the ability to fly longer and further than smaller moths reared at a higher temperature. Relative wing length (forewing length/thoracic length) was almost constant irrespective of temperature condition. Photoperiod had no effect on either forewing length or flight ability. Furthermore, parental body size did not significantly influence the flight ability of male adult progeny. It was experimentally verified that flight ability is influenced by adult body size in terms of forewing length. Forewing length is determined solely by temperature conditions during the larval stage, and flight ability (duration and distance) was significantly correlated with forewing length in P. xylostella. However, the potential of this species for long migration cannot be predicted from the present data, because the rates of moths with long consecutive flight and flight velocity were not significantly correlated with either larval rearing temperature or adult forewing length.