Effect of fasting on hypogean (Niphargus stygius) and epigean (Gammarus fossarum) amphipods: a laboratory study

Abstract

Two amphipods, the hypogean Niphargus stygius and epigean Gammarus fossarum, were analyzed for fatty acid (FA) composition, electron transport system (ETS) activity and respiration (R) during a laboratory fasting experiment. In agreement with ETS and R measurements (and the ETS/R ratio), the hypogean N. stygius utilized FA more slowly than the epigean G. fossarum. Inter-specific differences in the utilization of certain FA during fasting were also revealed. While N. stygius tended to preserve all of its FA during the experimental fasting period, G. fossarum showed a tendency to utilize MUFA (monounsaturated FA) and SAFA (saturated FA) and preferentially retain PUFA (polyunsaturated FA). The significant correlations between ETS activity and composition of specific FA during fasting can be linked to R. During the fasting, both ETS activity and respiration rate of G. fossarum decreased, however, ETS/R ratio increased. In contrast, N. stygius did not show significant changes in these parameters. This is the first report, which connects ETS activity with changes in concentrations of specific FA during fasting. Such evolutionary adaptations of hypogean species enables them to better survive chronically low and/or discontinuous food supplies compared to epigean species, which live in environments where food shortages are much less frequent.

Famine and feast in a common freshwater calanoid: Effects of diet and temperature on fatty acid dynamics of Eudiaptomus gracilis

“…Therefore, given the physiological importance of PUFA and that they are mostly obtained from diet (so that such losses in PUFA are irreversible as long as feeding is not resumed), our observations on fasting Eudiaptomus PLFA seem counterintuitive. Preferential PUFA retention during fasting has been shown in other taxa, such as cladocerans (Schlechtriem et al 2006) and amphipods (Mezek et al 2010). The mass fractions of several PUFA also decreased more quickly than those of SAFA and MUFA in a fasting experiment with Calanus (Mayor et al 2011).…”

The groundwater invertebrate fauna of the Channel Islands

“…The higher energetic requirements of epigean species (i.e. stygoxenes) which prevent their existence in subterranean environments for extended periods have been well studied in amphipods (Mezek et al 2010). In Britain D. bicuspidatus has been collected from many wells in chalk, remote from surface water and in association with N. fontanus and N. kochianus and is also known from at least three caves.…”

The Role of Microbes in the Nutrition of Detritivorous Invertebrates: A Stoichiometric Analysis

“…Zooplankton are DHA-limited in the detritivorous pathway throughout the parameter domain (Figure 3A). Recent work has shown that a range of aquatic invertebrates, including marine zooplankton, catabolize essential PUFAs at high rates (Mezek et al, 2010; Mayor et al, 2011, 2015; Maity et al, 2012) in which case our default zooplankton NPE for DHA of 0.9 (Anderson and Pond, 2000; Mayor et al, 2009) may be too high. Reducing the value of this parameter results in a proportional lowering of predicted zooplankton growth, to the extent that the detritivorous pathway becomes an inferior source of nutrition relative to the microbial pathway (in areas of the plane shown in Figure 3A that are lower than those of the corresponding parameter space shown in Figure 3B).…”