Feeding in the frequency domain: coarser‐grained environments increase consumer sensitivity to resource variability, covariance and phase

Abstract

Theory predicts that resource variability hinders consumer performance. How this effect depends on the temporal structure of resource fluctuations encountered by individuals remains poorly understood. Combining modelling and growth experiments with Daphnia magna, we decompose the complexity of resource fluctuations and test the effect of resource variance, supply peak timing (i.e. phase) and co‐limiting resource covariance along a gradient from high to low frequencies reflecting fine‐ to coarse‐grained environments. Our results show that resource storage can buffer growth at high frequencies, but yields a sensitivity of growth to resource peak timing at lower ones. When two resources covary, negative covariance causes stronger growth depression at low frequencies. However, negative covariance might be beneficial at intermediate frequencies, an effect that can be explained by digestive acclimation. Our study provides a mechanistic basis for understanding how alterations of the environmental grain size affect consumers experiencing variable nutritional quality in nature.

Spatial covariance reverses the compound effect of multiple stressors on rocky shore biofilm

“…2012(Pincebourde et al . , 2016Koussoroplis and Waker 2016;Koussoroplis et al 2017Koussoroplis et al -2019. Consideration of multiple factors and their covariation provides a more realistic view of the performance of organisms in fluctuating environments, compared to the analysis of individual factors.…”

“…Despite the widely recognised importance of environmental variability in influencing organisms' performance, few studies have explored the consequences of Jensen's inequality in a multifactorial context, incorporating the effect of covariation between variables (Pincebourdeet al 2012;Koussoroplis & Wacker 2016;Koussoroplis et al 2019). The simultaneous effect of multiple factors may produce nonlinearities that would remain undetected in a unifactorial scenario (Koussoroplis et al 2017).…”

“…These nonlinearities may interact with environmental variance and with the degree and direction of the covariance among environmental factors, leading to a deviation between organism's performance under constant and variable conditions. Direct evidence of the role of covariance in modulating organisms' performance stems from recent laboratory and mesocosm experiments (Pincebourdeet al 2012;Koussoroplis & Wacker 2016;Koussoroplis et al 2019). For instance, Koussoroplis and colleagues (2016) have shown how covariation between temperature and resource supply influenced the life-history traits of the water flea Daphnia magna .…”

Inter- and intraspecific differences in rotifer fatty acid composition during acclimation to low-quality food

“…In general, strain-and species-specific differences in fatty acid profiles imply differences in nutritional demands, which are accompanied by differences in functional traits acting on organismal performance, e.g. uptake rates, conversion efficiencies or retention abilities [44,45]. When rotifers are confronted with low dietary PUFA concentrations, their body PUFA concentrations may approach certain thresholds over time, potentially reflecting their basic physiological requirements (see electronic supplementary material, S3).…”

Lineage diversity, morphological and genetic divergence in Daphnia magna (Crustacea) among Chinese lakes at different altitudes

“…The many species in the cladoceran genus Daphnia Müller, 1785 (Anomopoda: Daphniidae) are among the most important com-ponents of freshwater ecosystems, being key grazers of phytoplankton as well as main prey for planktivorous fish (Lampert, 2011). Daphnia magna Straus, 1820 has been frequently subjected to ecotoxicological, ecological, evolutionary, biogeographical and physiological studies (e.g., De Gelas & De Meester, 2005;Koussoroplis et al, 2019;Lee et al, 2019;Seyoum & Pradhan, 2019). This species is widely distributed, being detected in Africa, Asia, Europe and North America (e.g., Bekker et al, 2018;Brooks, 1957;Fields et al, 2015;Xu et al, 2018).…”