Abstracts (first author)
Maternal exposure to predators: how to prepare offspring to a risky natal environment?PDF
Predation risk is a strong force inducing morphological, physiological and behavioural responses. As predation risk is often higher in early life, antipredator defences should be produced at a juvenile stage. Maternal effects are a good tool to produce antipredator defences early in juvenile life. We investigated if maternal exposure to predator cues during gestation affected juvenile morphology, behaviour at birth and life-history traits in common lizard (Zootoca vivipara). We exposed 22 adult females to cues from a saurophagous snake (Hierophis viridiflavus) for one month of gestation and 22 other females were kept unexposed. At birth, juveniles were measured and tested for thermal preferences and activity levels in presence or in absence of predator cues, and then released in semi-natural enclosures connected to a corridor allowing to monitor dispersal. We also quantified survival and growth rate at the end of the season by capture-recapture sessions. Offspring born from exposed mothers had longer tails at birth and at an older age and preferred lower temperatures than juveniles from unexposed mothers. Tail autotomy and decreased basking behaviour are common antipredator behaviours and thus our results suggest that mothers can prepare juveniles to risky environments. Juveniles from exposed mothers also increased their activity levels in response predator cues showing better abilities to recognize such cues. This increased activity, along with an overall increase in dispersal probability, show that mother also manipulated juvenile flight response. In response to predation risk, mothers can manipulate offspring phenotype to make them more adapted to their natal environment or increase their dispersal ability to find more suitable habitats. Our results show that, in common lizards, these two adaptive mechanisms act conjointly in order to improve offspring survival to predators.