Communal egg laying area of the American crocodile (Crocodylus acutus Cuvier,1807) in a tropical lagoon of Oaxaca, Mexico

Resumen

For crocodilians, successful nesting has an important effect on population dynamics and it is an excellent indicator of how a species adapts to its environment. The choice of the oviposition site and its environmental conditions will influence embryo development and offspring phenotypes. Nesting success for communal egg-laying in crocodilian nests has not been studied in depth. Our aim in this study was to describe the nesting ecology of a communal egg-laying area of the American crocodile (Crocodylus acutus) in the Palmasola lagoon on the coast of Oaxaca. Intensive searches around the lagoon were carried out daily to detect signs of nesting activity and identify potential sites for oviposition. We registered 27 nests for the 2018 reproductive season. Twenty-four nests were located divided into five clusters (Communal egg-laying, CEL) and the rest (n= 3) were classified as isolated nests. The most important CEL site found in the study area presented a grouping of 13 nests, with a mean distance between nests of 0.70 cm ± 0.35 cm S.D., and a mean clutch size of 34.5 ± 7.1 eggs. Our field observation is the first record of communal egg-laying of American crocodile in the Mexican Pacific slope and can be an indicator of active selection of the nesting areas by females of different sizes. Further studies are needed to provide new insights about the ecological and evolutionary consequences of communal egg-laying on the Mexican Pacific coast.