Survival and reproduction when food is scarce: implications for a lekking Hawaiian Drosophila

Abstract

Abstract. 1. In insects, larval diet can have a major impact on development, survival, and reproductive success. However, resource availability at the adult phase of the life cycle is also likely to have strong effects in species where there is an extended period of sexual maturation following adult eclosion.2. The effect of diet on the survival and reproductive success of the lekking Hawaiian fruit fly, Drosophila grimshawi, was explored. Two generations of emerging adults were exposed to one of two feeding regimes: ‘constant’ and ‘varied’ (corresponding to food ‘each day’ or ‘every other day’ respectively). The impact of resource availability on survival and reproductive success in each generation was then investigated.3. The probability of survival to 5 weeks old was higher for individuals fed a constant diet than individuals fed a varied diet, but was comparable for males and females.4. There was a significant maternal effect on offspring survival. Offspring whose mothers were reared on a constant feeding regime had higher survival than offspring whose mothers were reared on a varied diet.5. There was no relationship between feeding regime and the quantity of pheromones deposited by males (a measure of male reproductive investment); however F2 sons were more likely to deposit pheromones and deposited a larger quantity of pheromone than their F1 sires. The number and sex ratio of offspring (a measure of female reproductive effort) emerging from the F1 generation was unrelated to maternal or paternal feeding regime.6. The implications of variation in the foraging environment for mate choice in D. grimshawi are discussed.