ECOLOGICAL CONSEQUENCES OF BODY SIZE IN NEONATAL AND SMALL-BODIED LIZARDS IN THE NEOTROPICS

I investigated the relationship between lizard body size and prey size, particularly as it relates to challenges faced by neonatal lizards in the Neotropics. Within the large-bodied teiid lizard Ameiva ameiva, juveniles feed on smaller prey than adults, but adults continue to feed on prey eaten by juveniles. Adults eat invertebrates and vertebrates, including other lizards, and these likely have a much higher payoff in terms of energy gained per unit risk. Prey types and sizes vary among lizard species in an Amazonian rain forest near the Rio Curua-Una. Larger lizard species feed on larger prey, and smaller lizards, by virtue of their small body sizes, cannot feed on many prey taken by large lizards. Large lizards continue to take small prey. The larger non-vertebrate prey taken by lizards in this assemblage are mostly spiders and centipedes, many of which are larger than smaller lizard species and individuals. A combined data set from numerous Neotropical sites shows that the trend observed at the Curua-Una is a general one even though the smallest clade of lizards eat prey smaller than predicted based on body size alone. I suggest that small lizards, neonates in particular, are at great risk in diverse lizard assemblages because of their body size relative to other organisms. They likely compete with adults of their own and other species for food, they are eaten by larger lizards and other vertebrates, and they are likely prey for numerous highly abundant predaceous arthropods, especially spiders and centipedes.