RESOURCE DEPENDENT GROWTH AND BODY CONDITION DYNAMICS IN JUVENILE SNAKES - AN EXPERIMENT

We examined the manner in which animals adjust the proportion of energ y allocated to growth and storage in response to food availability. We compared univariate growth and length-mass relationships between juve nile adders (Vipera berus) reared under two different feeding regimes. Animals in the low- and high-food experimental groups were fed suckli ng mice once and twice weekly, respectively. Snout-vent length, body m ass, and body condition (residual scores from log-log regression of bo dy mass on snout-vent length) were measured shortly after birth, and a t 4, 9, and 14 weeks. We found that growth in length and mass, as well as changes in length-mass relationships, differed between treatments; snakes with access to more food not only increased faster in length b ut were also heavier at the completion of the experiment than were sim ilar sized less frequently fed snakes. There was no association betwee n body condition of individuals measured at birth and at the end of th e experiment, whereas size at birth was a good predictor of final size . Our results provide evidence for resource-dependent allocation strat egies in V. berus, and suggest that somatic growth is less sensitive t o environmental fluctuations than body condition, presumably because b ody size is of greater importance for fitness.