TY - JOUR A1 - Reinhard, Sandy A1 - Kupfer, Alexander T1 - Sexual dimorphism in a French population of the marbled newt, Triturus marmoratus (Urodela: Salamandridae) JF - Salamandra : German journal of herpetology N2 - Amphibians have developed a large set of life-history strategies and demonstrate an impressive diversity of reproductive patterns compared to other vertebrates. Various selection pressures impact on males and females and see them produce different degrees of sexual dimorphism in order to maximise their reproductive success. In an extended morphometric analysis that included 27 body-and head-related characters, we studied the pattern of sexual dimorphism of a French population of the marbled newt, Triturus marmoratus. We analysed the characters by employing GLM methods (ANCOVA) and found 16 of them to be dimorphic between the sexes. In general, females differ in head-body size, such as snout-vent length, but males rather in shape or body proportions (e.g., limb proportions). The various expressions of sexual size dimorphism among large-bodied marbled newts and allies demonstrate that more than one evolutionary model works simultaneously on different traits. KW - SSD KW - fecundity KW - sexual selection KW - salamanders KW - Triturus KW - morphometrics Y1 - 2015 SN - 0036-3375 VL - 51 IS - 2 SP - 121 EP - 128 PB - Deutsche Gesellschaft für Herpetologie und Terrarienkunde CY - Darmstadt ER - TY - JOUR A1 - Schälicke, Svenja A1 - Sobisch, Lydia-Yasmin A1 - Martin-Creuzburg, Dominik A1 - Wacker, Alexander T1 - Food quantity-quality co-limitation BT - interactive effects of dietary carbon and essential lipid supply on population growth of a freshwater rotifer JF - Freshwater biology N2 - Food quantity and quality are highly variable in natural systems. Therefore, their interplay and the associated effects on consumer population growth are important for predator-prey interactions and community dynamics. Experiments in which consumers were exposed to elemental nutrient limitations along food quantity gradients suggest that food quality effects on consumer performance are relevant only at high food quantities. However, elemental nutrients act differently on physiological processes than biochemical nutrients. So far, the interactive effects of food quantity and biochemical compounds on consumer performance have been insufficiently studied. We studied interactive effects of food quantity and biochemical food quality on population growth, including fecundity and survival, of the freshwater rotifer Brachionus calyciflorus. We hypothesised that these life history traits are differently affected by the availability of biochemical nutrients and that food quality effects gain importance with increasing food quantity. In a first experiment, we established food quantity and quality gradients by providing rotifers with different concentrations of a low-quality food, the sterol-free cyanobacterium Synechococcus elongatus, supplemented with increasing amounts of cholesterol. In a second experiment, food quantity and quality gradients were established by providing different proportions of two prey species differing in biochemical food quality, i.e. S.elongatus and the lipid-rich alga Nannochloropsis limnetica, at different total food concentrations. We found that the effects of cholesterol supplementation on population growth increased with increasing food quantity. This interactive effect on population growth was mainly due to food quality effects on fecundity, as effects on survival remained constant along the food quantity gradient. In contrast, when feeding on the mixed algal diet, the food quality effect associated with increasing the proportion of the high-quality alga did not change along the food quantity gradient. The data on survival and fecundity demonstrate the missing interactive effect of food quantity and quality on population growth, as both traits were oppositely affected. Survival was affected by food quality primarily at low food quantity, whereas food quality effects on fecundity were stronger at high food quantity. Our results highlight the significance of essential biochemicals in mediating the interactive effects of food quantity and quality on population growth. The interplay between food quantity and biochemical food quality limitation seems to influence resource allocation patterns in order to optimise survival or reproduction, which may strongly affect population dynamics in variable environments. As opposed to exploring the function of a single nutrient via supplementation, using algae mixtures allowed us to assess food quality effects on consumer performance in a more natural context by taking potential interactive effects of multiple co-limiting nutrients into account. KW - Brachionus calyciflorus KW - fecundity KW - population growth rate KW - sterols KW - survival Y1 - 2019 U6 - https://doi.org/10.1111/fwb.13272 SN - 0046-5070 SN - 1365-2427 VL - 64 IS - 5 SP - 903 EP - 912 PB - Wiley CY - Hoboken ER -