Elemental stoichiometry of Drosophila and their hosts

Abstract

1. Nitrogen (N) and phosphorus (P) availabilities are important ecological determinants of resource use in nature. Despite the wide range of hosts used by species of the genus Drosophila, elemental composition of natural resources of these flies has never been investigated. 2. Total body N and P contents were determined in seven species of wild‐caught Drosophila, their natural hosts, and artificial diets routinely used to rear these flies in the laboratory. The flies tested included D. hydei, D. arizonae, D. simulans and D. pseudoobscura collected from rotting fruit (melons), and the cactophilic D. nigrospiracula, D. mojavensis and D. pachea collected from their specific host plants, Saguaro, Organpipe and Senita cactus, respectively. 3. Natural hosts varied in elemental composition, with fruit showing higher N (2·8–4·3% dry mass) and P (0·50–0·67%) levels compared with cacti (0·5–1·6% N; 0·01–0·29% P). No consistent differences in N and P levels were found between healthy and necrotic cactus tissue. 4. Total body N and P also varied among Drosophila species. This variation mirrored the levels of N and P found in the respective hosts and laboratory diets. N:P ratios were consistently lower in female flies compared with conspecific males suggesting phosphorus demands during oogenesis are high. 5. Potential mechanisms by which Drosophila deal with N or P limitation in nature are discussed.

Subsidy–stress response of macroinvertebrate community biomass to a phosphorus gradient in an oligotrophic wetland ecosystem

“…P content of invertebrates that produce a single (usually large) batch of eggs (semelparous taxa) may increase as larvae mature. Percent P of somatic tissue is less than that of gametes (especially eggs) in the few taxa examined (Andersen and Hessen 1991, Markow et al 1999, 2001, but see Faerøvig and Hessen 2003). P content of iteroparous taxa (reproduce multiple times, fewer eggs) probably declines as larvae grow because adults can feed and supply nutrients necessary for maintenance and reproduction.…”

Sex-specific nutrient use and preferential allocation of resources to a sexually selected trait in Hyalella amphipods

“…The sexes can differ markedly in elemental composition, with these differences changing across different life stages (Back and King, 2013;Goos et al, 2014;Gorokhova and Hansson, 2000;Markow et al, 1999). Thus, the supply of necessary elements in the environment could invoke sex-and/or age-specific element use strategies, particularly in species exhibiting high degrees of sexual dimorphism.…”

Dietary protein content affects evolution for body size, body fat and viability in Drosophila melanogaster

“…Studies concerned with the impact of nutrition often assess the physiological and morphological responses of individuals exposed to different quality and amount of nutrients. These include studies of the impact of nutrition on body composition [4,5], stress tolerance [6,7], and reproduction and longevity [8 -11]. Less is known about the long-term/evolutionary consequences of transitions to different diets, although the potential interactions between 'historical' and 'present' diets will ultimately determine the fitness of the resulting phenotype.…”

“…Drosophila melanogaster is known to feed and breed on ripe or rotting fruit [18] where protein/carbohydrate ratios vary temporarily and spatially [4,19]. Together with the fact that D. melanogaster has a short generation time, this makes this species ideal for experimental studies aiming at investigating how diet composition shape the evolution of life-history traits.…”