Preimaginal environment influences adult flight in Cydia molesta (Lepidoptera:Tortricidae)

Dispersal of adult tortricid moths between habitats may have important consequences for pest management in orchards, but little is known about how flight parameters are affected by environmental conditions during preimaginal development. The influence of changing temperature and photoperiod (both singly and in combination) as well as of larval crowding and food deprivation were investigated in Cydia molesta Busck (Lepidoptera: Tortricidae), a species that has been found to disperse after peach harvest and colonize pome fruit orchards. Comparative assessments of flight parameters were made on a computer-linked flight mill and life history traits were evaluated. A significant increase in flight performance was correlated with preimaginal exposure to decreasing photoperiod. In addition, pupal development was delayed and larger individuals emerged, but preimaginal survivorship was reduced. Decreasing and increasing temperature regimens and increasing photoperiod did not influence adult flight. Larval crowding was associated with increased flight, but the differences were not statistically significant. Food deprivation was associated with accelerated preimaginal development, lower pupal weight, less fecund adults,and reduced flight. We propose that the main factor eliciting dispersal in this tortricid is decreasing photoperiod.