Does solitary incubation enhance egg water uptake and offspring quality in a lizard that produces single-egg clutches?

Many organisms invariably produce one offspring per reproductive bout, but experimental tests of adaptive explanations for this reproductive pattern are rare. To address this issue, we studied a lizard (Anolis sagrei) that produces one egg at a time to test the hypothesis that solitary incubation (due to single-egg clutches) eliminates competition with adjacent eggs for moisture and thus enhances offspring quality via increased egg water uptake during development. Our findings suggest that solitary incubation does not affect rates of moisture uptake by eggs or offspring size. However, egg moisture uptake and offspring size were negatively affected when eggs were adjacent to an egg that died during development. Depending on rates of infertile eggs or embryo mortality in the field, single-egg clutches may improve developmental environments and enhance offspring fitness. These results highlight the importance of considering the role of plastic embryonic responses during development in explaining reproductive patterns.