Different impacts of diet composition on the stoichiometric traits of two freshwater species

Body elemental composition of consumers is a crucial parameter linking organisms’ attributes to environmental changes. Recent investigations have revealed substantial intraspecific variability in organismal stoichiometry, challenging the assumption that individuals within a population have similar elemental composition. Yet, disentangling the factors that promote intraspecific variation in organismal stoichiometry remains important. Here, we experimentally assessed the effect of diet elemental composition on the stoichiometric traits [percentage and ratios of carbon (C), nitrogen (N) and phosphorus (P)] of two omnivorous species, the red swamp crayfish (Procambarus clarkii) and the pumpkinseed sunfish (Lepomis gibbosus). Sunfish exhibited 6 times higher P and 1.6 times higher N contents than crayfish. Diet composition was an important driver of organismal stoichiometry variation within species, but its effect was also taxon-dependent. Our study revealed that the effects of diet variability on intraspecific stoichiometric traits are important but also contingent on the taxonomy.