Meeting Abstract

44.8  Saturday, Jan. 5  Reproductive allometry and the size-number trade-off for lizards WARNE, R.W.*; CHARNOV, E.L.; WOLF, B.O.; Univ. of New Mexico rwarne@unm.edu

Fundamental to life history theory is the assumed inverse proportionality between the number of offspring and the resource allocation per offspring. Lizards have been model organisms for empirical tests of this theory for decades; yet the expected negative relationship between clutch-size and offspring-size is often not detected. Here we use an approach developed by Charnov and Ernest to demonstrate that this often concealed trade-off can be made apparent in an inter-specific comparison by correcting for size dependent resource allocation. To account for non-independence of comparative data we also show that this correction is robust by a full phylogenetic analysis via independent contrasts and a composite phylogeny assembled from published studies. Our dataset also shows a tight allometry for annual production that is consistent with life history models for indeterminate growers. Combined these results demonstrate that the offspring-size/clutch-size trade-off is not isolated to a single clutch, but is shaped by the resource investment over an entire year. We conclude that across diverse lizard species there is strong evidence for the predicted trade-off between offspring size and the annual number of eggs produced.