A trade‐off between current and future fitness potentially explains variation in life‐history strategies. A proposed mechanism behind this is parasite‐mediated reproductive costs: individuals that allocate more resources to reproduction have fewer to allocate to defence against parasites, reducing future fitness. We examined how reproduction influenced faecal egg counts (FEC) of strongyle nematodes using data collected between 1989 and 2008 from a wild population of Soay sheep in the St. Kilda archipelago, Scotland (741 individuals). Increased reproduction was associated with increased FEC during the lambing season: females that gave birth, and particularly those that weaned a lamb, had higher FEC than females that failed to reproduce. Structural equation modelling revealed future reproductive costs: a positive effect of reproduction on spring FEC and a negative effect on summer body weight were negatively associated with overwinter survival. Overall, we provide evidence that parasite resistance and body weight are important mediators of survival costs of reproduction.

Cities are not often considered priority areas for threatened mammals; however, recent research suggests that urban areas may be important for water vole (Arvicola amphibius) conservation. To establish the potential importance of cities in supporting water vole populations we used National Biodiversity Network (NBN) Atlas data to examine the occurrence of water voles within the United Kingdom (UK). Water voles were recorded in 28 out of 64 official UK cities in the last decade (2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017)(2018), and rivers and streams within parks, sports grounds, and urban reserves were the most important habitat types. In total, we found 497 records of water vole sightings within official cities, representing 2 5.0% of all records for this species in the NBN Atlas. Our results show that water voles are indeed found within many cities, suggesting that urban populations of water voles are more common in the UK than previously recognised. We therefore recommend that the importance of these urban populations for conservation of this species should be further established.

No abstract

Body size may influence ectotherm behaviour by influencing heating and cooling rates, thereby constraining the time of day that some individuals can be active. The time of day at which turtles nest, for instance, is hypothesized to vary with body size at both inter- and intra-specific levels because large individuals have greater thermal inertia, retaining preferred body temperatures for a longer period of time. We use decades of data on thousands of individual nests from Algonquin Park, Canada, to explore how body size is associated with nesting behaviour in painted turtles (Chrysemys picta (Schneider, 1783), small bodied) and snapping turtles (Chelydra serpentina (Linnaeus, 1758), large bodied). We found that (1) between species, painted turtles nest earlier in the evening and at higher mean temperatures than snapping turtles, (2) within species, relatively large individuals of both species nest at cooler temperatures, and relatively larger painted turtles nest later in the evening compared to smaller painted turtles. Our data support the thermal inertia hypothesis, and may help explain why turtles in general exhibit geographic clines in body size: northern environments experience more daily variation in temperature, and larger size may evolve, in part, for retention of preferred body temperature during terrestrial forays.