Effects of protein availability on locomotor activity and oogenesis in female Sarcophaga crassipalpis

Females of the anautogenous flesh fly, Sarcophaga crassipalpis are oviviparous, synchronize the maturation of eggs in clutches, and require a protein meal to develop eggs to maturity. We have examined the effects of sex and nutrition on the timing and intensity of fly locomotor activity over adult developmental time after eclosion. Groups of males and unmated females were allowed limited access to liver for two days on days 1&2, 3&4, 5&6, 7&8, 9&10, or 11&12, post-eclosion. Unfed control treatment groups were also examined. For all groups, locomotor activity patterns were measured for fifteen days (LD 12:12, 25⁰C). Fecundity, egg size, and progression of oogenesis were also measured. As expected for a diurnal organism, the males exhibited exclusively diurnal activity despite nutritional changes. However, females fed a protein meal displayed extensive nocturnal activity that depended on the timing of protein availability with activity peaks occurring 1-2 days after protein feeding. Females not fed a protein meal displayed nocturnal activity on days 6-10. Differences in diet had a significant effect on egg length, fecundity, and the rate of egg provisioning. There appears to be a link between the beginning of egg provisioning and the timing of nocturnal activity in females fed liver. Female nocturnal activity may reflect a link between nutrition, oogenesis, and locomotor activity.