INFLUENCES OF DIET AND FAMILY ON AGE OF MATURATION IN BROWN HOUSE SNAKES, LAMPROPHIS FULIGINOSUS

One of the most important life-history traits for organisms is age at first reproduction. The benefits of early reproduction often trade off with survival of the female and/or with her growth. Prey availability has been shown to be important in determining strategies for adult trade-offs of reproductive traits in snakes, but its impact on maturity has rarely been studied. We examined the role of energy intake on the brown house snake, Lamprophis fuliginosus, on trade-offs in growth, maturity, and reproductive traits. Six female full-sibling offspring from 10 wild-caught dams were raised on either a high diet (50% of their body mass per week) or a low diet (20% per week) until they mated and laid eggs. Both diet and family influenced growth rates. Forty-eight out of 60 snakes mated, and 37 of these laid eggs within the 20 months. Mean days to first mating was nearly 100 days earlier for animals on the high diet. Within each treatment females did not differ from each other in mating age. The females on the low diet mated at a smaller size than the females on the high diet and laid fewer eggs. However, when adjusted by female snout-to-vent length as a covariate clutch size did not differ between diets. These results suggest there is a minimum size and age below which females will not ovulate. Females with faster growth may bypass that minimum even though earlier reproduction would produce a faster generation time. The trade-off with increased reproductive output in these bigger females may offset the benefits of an earlier maturity and produce equivalent fitness. Finally, we provide evidence that age of maturity may have an additive genetic effect, i.e., may be heritable and thus evolvable based on a significant family effect.