The Effects of Age and Size on Reproductive Timing in Female Chamaeleo chamaeleon

Abstract

Reproductive timing in relation to the size and age of individual female common Chame- leons (Chamaeleo chamaeleon) was studied in a population in southern Spain. Thirty-one radio-tagged fe- males were observed during two summers, 1993 and 1995. The mating season (courting, pair formation, and copulation) lasted from late July to mid-September. Egg-laying was recorded from 25 September to 28 October, 34-40 d after copulation. Timing of reproduction varied between individual females, old and large females timing the reproductive events (i.e, mating and egg-laying) earlier than young and small ones. Specifically, timing was affected by size when age was controlled for but not the reverse. Four alternative explanations for delayed breeding of younger and smaller female chameleons are discussed: (1) late breeding could be a consequence of physiological constrains in the onset of maturation of younger females; (2) late breeding allows young females to secure more resources for reproduction thus achieving larger clutches; (3) young females avoid competition for attractive males from large females, and (4) if young females are less preferred, they may not be courted until males no longer are courting larger females. This happens when the latter become pregnant.