The influence of propagule size and maternal nest-site selection on survival and behaviour of neonate turtles

Abstract

1. Maternal effects are widely recognized as important ecological and evolutionary forces, with fitness consequences for both offspring and parents. However, little is known about the impact of maternal effects on the survival and behaviour of offspring in the field. Two potentially important maternal effects that influence the phenotypes and survival of neonates are (i) propagule size effects (i.e. egg size, hatchling size and clutch effects) and (ii) nest-site selection, which influences incubation conditions and the suitability of habitat for neonates after hatching. 2. We experimentally removed the effects of variable incubation conditions to focus on how propagule size effects and nest-site microhabitat characteristics influence hatchling survival and behaviour in the Common Snapping Turtle, Chelydra serpentina. Using eight simultaneous experimental releases of neonates under ecologically relevant field conditions, we detected no influence of propagule size effects on hatchling turtle survival or behaviour. Egg mass, hatchling mass, hatchling carapace length and clutch did not predict the probability of survival, nor did they influence hatchling behaviour. 3. However, nest-site microhabitat characteristics were important for both survival and behaviour. The probability of hatchling survival increased with decreasing amounts of ground vegetation and slope at the release point. Hatchlings took longer to reach the fence when released in areas with more ground vegetation and dispersed farther when released from greater distances and at lower slopes. Therefore, variation in maternal behaviour, such as nest-site selection, is an important effect because it results in differential survival and behaviour of offspring in this population, whereas variation in maternal size effects alone does not.