Abstract
Interspecific differences in organismal stoichiometry (OS) have been documented in a wide range of animal taxa and are of significant interest for understanding evolutionary patterns in OS. In contrast, intraspecific variation in animal OS has generally been treated as analytical noise or random variation, even though available data suggest intraspecific variability in OS is widespread. Here, we assess how intraspecific variation in OS affects inferences about interspecific OS differences using two co-occurring Neotropical fishes: Poecilia reticulata and Rivulus hartii. A wide range of OS has been observed within both species and has been attributed to environmental differences among stream systems. We assess the contributions of species identity, stream system, and the interactions between stream and species to variability in N:P, C:P, and C:N. Because predation pressure can impact the foraging ecology and life-history traits of fishes, we compare predictors of OS between communities that include predators, and communities where predators are absent. We find that species identity is the strongest predictor of N:P, while stream or the interaction of stream and species contribute more to the overall variation in C:P and C:N. Interspecific differences in N:P, C:P, and C:N are therefore not consistent among streams. The relative contribution of stream or species to OS qualitatively changes between the two predation communities, but these differences do not have appreciable effects in interspecific patterns. We conclude that although species identity is a significant predictor of OS, intraspecific OS is sometimes sufficient to overwhelm or obfuscate interspecific differences in OS.
Highlights
Organismal stoichiometry (OS) defined as the ratios of elements in animals is an important trait because it is used to calculate nutritional demand, and because of its potential to constrain a range of ecological processes (Elser and Urabe 1999; Elser et al 2000; Frost et al 2006)
OS varies with body size, morphology, and life-history traits because these traits affect biochemical composition, which controls the elemental composition of animals (Tanner et al 2000; Sterner and Elser 2002; Gonzalez et al 2011)
Ecology and Evolution published by John Wiley & Sons Ltd
Summary
Organismal stoichiometry (OS) defined as the ratios of elements in animals is an important trait because it is used to calculate nutritional demand, and because of its potential to constrain a range of ecological processes (Elser and Urabe 1999; Elser et al 2000; Frost et al 2006). Mismatches between elemental requirements of animals and the elemental content of their diets have significant consequences for many ecological and biogeochemical processes, including population dynamics, feeding rates, nutrient recycling, and competition Characterizing interspecific patterns in OS can improve our understanding of the links between evolutionary innovations and biogeochemical cycling, and can clarify evolutionary patterns in nutritional requirements and thresholds (Kay et al 2005; Frost et al 2006).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.