Food availability induces geographic variation in reproductive timing of an aquatic oviparous snake (Natrix maura)

Abstract

The viperine snake Natrix maura is a common water snake, which forages on aquatic prey such as fish and frogs in Western Mediterranean water bodies. Female viperine snakes collected from three populations at the Iberian Peninsula during the vitellogenesis period were compared. Mean clutch size and range, as well as the slope of the regression between body size and clutch size, did not show differences between populations. In contrast, mean size of enlarged follicles of females collected in May from the Ebro Delta proved significantly smaller than those of females from the Matarranya River (50 km far) and the Granada Depression (500 km far). There were no differences in climatic conditions between areas. However, seasonal variation in food availability was significantly different in the Ebro Delta. In this area, the rice fields are dry in early spring as men control the water flow, and prey are not available. This energetic constraint induced female viperine snakes to adjust reproductive timing according to seasonal availability and to delay vitellogenesis for at least one month. By contrast, other Mediterranean populations exhibited a rather high prey availability from early spring (e.g. Matarranya River), females being in good condition in this season and consequently vitellogenesis starting earlier than in the Ebro Delta. This study illustrates a new case of reproductive plasticity in snakes.

Factors affecting variation in the reproductive investment of female treefrogs, Hyla intermedia

“…Some females may be genetically more efficient than others in converting external resources into metabolic energy or they may experience different environmental conditions, because of the spatial or seasonal heterogeneity of prey abundance (Kaplan, 1987;Madsen and Shine, 1999;Reading, 2004;Santos et al, 2005). Whatever the causes (genes, environment or gene-environment interaction), if resource variation is responsible for variation in fecundity, then we should expect, at the population level, patterns of co-variation largely inconsistent with those predicted by lifehistory tradeoffs, because females that have larger resources at their disposal may invest more both in growth and in reproduction than females with few resources (de Jong and van Noordwijk, 1992;Roff and Fairbairn, 2007).…”

Weathering the Storm: The Implications of Wave Exposure on the Distribution, Phenotype and Growth of a Temperate Reef Fish

“…Species try to balance their seasonal breeding with both increasing resources following winter and seasonal limitations of disturbance (i.e., winter frosts, storms; Levin 1995, Post et al 2001). Many taxa have exhibited plasticity in reproductive timing with changing seasonal resources (Svensson et al 1995, Santos et al 2005, Tarayre et al 2007, Van Der Jeugd et al 2009). In heterogeneous environments, particularly with unpredictable disturbance, individuals increase their reproductive fitness by reproducing on different schedules (Post et al 2001).…”

Weathering The Storm: The Implications Of Wave Exposure On The Distribution, Phenotype And Growth Of A Temperate Reef Fish

“…Species try to balance their seasonal breeding with both increasing resources following winter and seasonal limitations of disturbance (i.e., winter frosts, storms; Levin 1995, Post et al 2001). Many taxa have exhibited plasticity in reproductive timing with changing seasonal resources (Svensson et al 1995, Santos et al 2005, Tarayre et al 2007, Van Der Jeugd et al 2009). In heterogeneous environments, particularly with unpredictable disturbance, individuals increase their reproductive fitness by reproducing on different schedules (Post et al 2001).…”