Record Details

Bock, Brian C;Rand, A Stanley
Factors influencing nesting synchrony and hatching success at a green iguana nesting aggregation in Panama
Journal Article
Iguana iguana
We observed a green iguana (Iguana iguana) nesting aggregation in Panama over four successive nesting seasons that had radical differences in rainfall. More than a threefold variation in rainfall between years had little effect on the timing of nesting but a pronounced effect on hatching success. Excessive soil moistures late in the incubation period resulted in almost complete nesting failure in 1 yr and probably contributed to the failure of some clutches in years with more moderate rainfall. In the first 3 yr of the study an American crocodile (Crocodylus acutus) also nested at this site and frequently interrupted iguana nesting activities, especially early in the season. Each year, a complex burrow system was established so that later nesting iguanas laid deeper and were less susceptible to crocodile attack or to clutch disturbance by subsequent nesting iguanas. The earliest hatchling iguanas to emerge were more likely to have tick infestations. We also suggest that a parasitic fly may affect iguanas that hatch late in the season. Oviposition occurred from 18 Feb.-18 March during this study and individual iguanas tended to nest on nearly the same dates each year. Such synchronous nesting is unusual for tropical lizards and suggests that there has been strong selection for the timing of nesting in the green iguana. Nesting interference, clutch failure due to excessive moistures, and parasitism on hatchling iguanas all principally affect either those clutches laid the earliest or latest each year and may contribute to the maintenance of nesting synchrony in this population.