Factors affecting the flight potential of Choristoneura conflictana , an insect that undergoes cyclical changes in population density, are investigated using computer-linked flight mills. Female and male moths are flown for a 12-h period and the longest single flight and total flight distance of each moth is recorded. After flight bioassays, moths are subjected to lipid extraction with a soxhlet apparatus to determine the effect of body lipid content on flight. Larger C. conflictana moths fly farther than smaller moths. Female C. conflictana fly farther than male moths but the effects of both mating status and moth age on the distance flown are dependent on sex. Mated females fly farther than virgins and older females fly farther than young females but these relationships do not occur in males. Body lipid content affects the distance flown by both females and males through a significant interaction with sex and age. The factors examined in this study will vary with density in natural populations and are predicted to be important indicators of flight potential and dispersal in this species.Science and Engineering Research Council of Canada (NSERC), and The Department of Biological Sciences, University of Alberta. Flight mills were generously provided by J. R. Spence, who, along with B. A. Keddie, provided valuable feedback on an earlier version of this manuscript. The flight mill program 'Flysumm' (2006) was modified by Steve Kembel and the data generated were organized with the assistance of Joshua Jacobs. Field and laboratory assistance were provided by Aleks Argals, Bradford Jones, and Joelle Lemmen.

Post-flight reproductive investment by female insects may be limited as a result of a trade-off in resource allocation between flight and reproduction. Outbreaking forest pests reduce their habitat quality as a result of severe defoliation when population densities are high. Female relocation to better-quality habitats can increase offspring survival but reduce their reproductive fitness through flight. In the present study, the effect of flight on the capacity of female Choristoneura conflictana (Walker) (Lepidoptera: Tortricidae) to mate and produce eggs is examined. Females are flown on flight mills, and the subsequent reproductive capacity of each moth is assessed through measures of mating success and egg production. There is no effect of flight on commencement or the duration of mating. Although flight does not affect egg production directly, energy expenditure as a result of flight (as measured by weight loss) shows a negative correlation to potential fecundity, possibly indicating the resorption of eggs in some females. The effect of female size on fecundity is dependent on mating status, suggesting that energy allocated to reproduction is not dependent on flight treatment. Female moth longevity also has a significant effect on egg production but is dependent on flight and mating treatments. There is a relationship between energy expenditure to flight and reproduction in C. conflictana. Females that fly away from dense populations may produce fewer offspring, although this cost may be mitigated by improved offspring survivorship in less defoliated habitats.

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