Differences in larval nutritional requirements and female oviposition preference reflect the order of fruit colonization of Zaprionus indianus and Drosophila simulans

Abstract

Species coexist using the same nutritional resource by partitioning it either in space or time, but few studies explore how species-specific nutritional requirements allow partitioning. Zaprionus indianus and Drosophila simulans co-exist in figs by invading the fruit at different stages; Z. indianus colonizes ripe figs, whereas D. simulans oviposits in decaying fruit. Larvae feed on yeast growing on the fruit, which serves as their primary protein source. Because yeast populations increase as fruit decays, we find that ripe fruit has lower protein content than rotting fruit. Therefore, we hypothesized that Z. indianus and D. simulans larvae differ in their dietary requirements for protein. We used nutritional geometry to assess the effects of protein and carbohydrate concentration in the larval diet on life history characters in both species. Survival, development time, and ovariole number respond differently to the composition of the larval diet, with Z. indianus generally performing better across a wider range of protein concentrations. Correspondingly, we found that Z. indianus females preferred to lay eggs on low protein foods, while D. simulans females chose higher protein foods for oviposition when competing with Z. indianus. We propose the different nutritional requirements and oviposition preference of these two species allows them to temporally partition their habitat.

Drosophila females trade off good nutrition with high quality oviposition sites when choosing foods

“…For instance, the composition of a ripening fig fruit changes from ca. P:C 1:10 to P:C 10,000:1 over the course of 27 days, with P and C concentrations varying between 10 and 10,000 g l −1 (Matavelli et al, 2015). These nutritional modifications of food resources are likely favoured by the fact that females inoculate the fruit substrate with yeast during oviposition (Buser et al, 2014;Stamps et al, 2012) and tend to lay eggs in aggregations (Navarro and del Solar, 1975;Prokopy and Roitberg, 2001;Wertheim et al, 2005; see also experiment 2).…”

“…In nature, as a fruit starts rotting and yeast populations grow, the composition of the fruit dynamically enriches in protein, thus providing food resources with increased P:C ratios (Matavelli et al, 2015;Morais et al, 1995). For instance, the composition of a ripening fig fruit changes from ca.…”

“…These nutritional modifications of food resources are likely favoured by the fact that females inoculate the fruit substrate with yeast during oviposition (Buser et al, 2014;Stamps et al, 2012) and tend to lay eggs in aggregations (Navarro and del Solar, 1975;Prokopy and Roitberg, 2001;Wertheim et al, 2005; see also experiment 2). In many cases, multiple fly species may also breed in the same fruits (Matavelli et al, 2015). These changes in nutrient balance and concentration mediated by the behaviour of females correlate with changes in the nutrient requirements of larvae as they develop.…”

“…Drosophila melanogaster (Lee, 2015;Lee et al, 2008Lee et al, , 2013Piper et al, 2014;Reddiex et al, 2013;Ribeiro and Dickson, 2010;Rodrigues et al, 2015); other fruit flies (Fanson et al, 2009;Matavelli et al, 2015)]. These effects of nutrition on physiology and behaviour greatly vary with age, sex and the mating status of individuals.…”

“…Maturation of fruits, from ripening to rotting, is accompanied by important modifications in the density and diversity of yeast populations (Morais et al, 1995), resulting in predictable variations in P:C ratios with the stage of fruit decay (Tournas and Katsoudas, 2005;Matavelli et al, 2015). Alternately, females may simply lay eggs on the foods they eat from.…”