Effects of climatic conditions on sex ratios in nests of broad-snouted caiman

SIMONCINI, M; CRUZ, F; LARRIERA A; PIÑA C

JOURNAL OF ZOOLOGY (1987)

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2014 vol. 293 p. 241 - 251

0952-8369

Caiman latirostris has temperature-dependent sex determination and is potentiallysusceptible to environmental temperature fluctuations and, thus, to the globalclimate change phenomena. Considering the potential consequences of increasingtemperatures for Ca. latirostris offspring, we examined the effects of climaticconditions on sex ratios produced by caimans in wild nests and in particular howclimate variables affect nest temperature and the percentage of females produced.We also explored the potential consequences of a hypothetic 0.5 and 1.0°Cincrease in nest temperature on caiman populations. The proportion of femalesproduced from nests in the wild varied among reproductive seasons, as mean nesttemperatures varied between 27.1 and 33.9°C. However, after seven seasons thesex ratio biased toward females, and only during extreme events (strong El NiñoSouthern Oscillation event, La Niña) was there a reduction in the percentage offemales produced in the wild. In the hypothetic scenarios of global warming, wepredict a decrease of unisexual female nests, with nests containing both sexes orunisexual male nests becoming more frequent. Entire clutches might be lost if nesttemperatures rise above 34.5°C for extended periods. However, it is possible thatfemales modify their nesting timing and behavior to select thermally suitable nestenvironments.