Organismal stoichiometry at the temporal scale: Seasonal variability shapes interspecific differences in fish

Abstract

Changes in organismal stoichiometry (OS) may be driven by seasonal changes in lipid reserves (i.e. energy) and gonadal development in fish. However, these relationships are understudied. Hence, we investigated how seasonal changes in body lipid content and gonadal development can drive the seasonal variability of OS traits at the example of three coexisting freshwater fish species. Furthermore, we aimed to assess the importance of seasonal OS alteration in comparison with interspecific differences. Carbon (%C), nitrogen (%N) and phosphorus (%P) contents, and the molar ratios of these elements (C:N, C:P and N:P) were examined in rudd (Scardinius erythrophthalmus), pumpkinseed (Lepomis gibbosus) and Amur sleeper (Perccottus glenii). We consider the sex and seasonal changes in body size as a potential factor in shaping OS. Substantial seasonal intraspecific variability occurred in all OS traits. Its extent exceeded interspecific differences in %C, %N and C:N, while %P and C:P, N:P were determined primarily by species identity. The effect of sex occurred sporadically and was considerable in some cases. Seasonal changes in total length did not contribute to intraspecific variability of OS. Intra‐annual changes in body lipid content affected seasonal variability of OS traits substantially, but the strength of this effect was species‐specific. The regulatory role of lipid reserve alterations worked only for those species that exhibited considerable seasonal variation in body fat content. Gonado‐somatic index proved to be marginal in shaping seasonal changes in OS, presumably because a substantial portion of the essential elemental demand for gonadal growth is supplied by rearrangements within the body, without notable changes in the entire elemental composition. In the light of our findings, we suggest that more attention should be given to the influence of seasonal variability in OS traits, and sex should be considered as a taxon‐dependent effect. Ignoring this substantial degree of variability might lead to inaccuracies in assessing the extent of both intra‐ and interspecific OS differences. We conclude that seasonal OS variability might shape consumer‐driven nutrient dynamics.

Environmental‐related variation of stoichiometric traits in body and organs of non‐native sailfin catfishes Pterygoplichthys spp

“…On the other hand, body size and sex had no significant impacts on body elemental contents, except for body %C. In this regard, male body %C was higher than female, which was not consistent with the previous study for Lepomis gibbosus and Perccottus glenii (Mozsar et al, 2019). Males of both species exhibited nest-guarding activities, resulting in a decline in %C due to food deprivation and energy reserves decrease (Pizzolon et al, 2012).…”

“…Also, differences in reproductive activity (i.e. nest guarding vs oviposition) and body size between females and males could drive sexual dimorphism in nutrient cycling and organismal stoichiometric traits (Ambus & Moody, 2019 ; Mozsar et al, 2019 ). Besides, biotic and abiotic environmental factors (i.e.…”

Elemental content of a host-parasite relationship in the threespine stickleback

“…S.solidus constitutes a large proportion of host biomass, so if they disproportionately uptake certain elements from the host, this could change host stoichiometry as well. To determine whether stickleback and S. solidus have distinct elemental compositions, we used paired t-tests to compare the species' means for %C, %N, and %P and their respective ratios, C:N, C:P, and N:P. In addition, we also 6 Prior studies have found significant variation in stoichiometry among individual fish (Vanni et al, 2002;Sterner and George, 2000;Mozsár et al 2019), which may lead to stoichiometric variation among parasites. For example, an increase in %N across hosts could be related to an increase in %N of its parasite.…”

“…Prior studies have found significant variation in stoichiometry among individual fish (Vanni et al, 2002; Sterner and George, 2000; Mozsár et al 2019), which may lead to stoichiometric variation among parasites. For example, an increase in %N across hosts could be related to an increase in %N of its parasite.…”

Consumer trait responses track change in resource supply along replicated thermal gradients

“…Consequently, there is a greater range in body size in females which may alter lipid demand or bone formation through ontogeny. In addition, differences in stoichiometry may occur via difference in reproductive state and stage of embryo development [ 75 ]. Regardless of the mechanism, our data provide evidence that fish elemental composition varies with temperature and sex.…”