The sex-determination pattern in crocodilians: A systematic review of three decades of research
Por:
Gonzalez, Edgar J., Martinez-Lopez, Marcela, Morales-Garduza M.A., Garcia-Morales, Rodrigo, Charruau, Pierre, Gallardo-Cruz J.A.
Publicada:
1 sep 2019
Ahead of Print:
1 jul 2019
Resumen:
Sex in crocodilians is not determined by chromosomes, but by egg
incubation temperature, where different temperatures produce different
clutch sex ratios. Two patterns have been proposed to describe these
changes in sex ratios: a 100% female proportion at low and high
temperatures with male predominance at intermediate ones (FMF) or a
simpler pattern with a single female-to-male transition (FM). Over the
last three decades, researchers have provided empirical information to
support either of these two patterns in different species; however, no
consensus has been reached partly because data have not been analysed as
a whole. Here, we aimed at gathering the existing data on these patterns
to provide models of temperature-dependent sex determination in those
crocodilians studied so far. Potentially relevant publications were
searched on Web of Knowledge, Scopus, Scielo and Science Direct. Studies
that reported results on the sexual identity of crocodilian hatchlings
obtained from constant temperature incubation treatments were
considered. Using statistical models varying in their underlying
assumptions, we evaluated which sex-determination pattern was best
supported for the studied crocodilians and constructed species-specific
and latitude-specific models. Based on the 8,458 sexed hatchlings
studied throughout 31 studies, we show that the evidence supports a
shared FMF pattern in all the crocodilian species for which enough data
are available. We find that such pattern changes between species and at
different latitudes. These results suggest a lability of the FMF
crocodilian sex-determination pattern, a key feature under the present
climate change scenario.
Filiaciones:
Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
Centro del Cambio Global y la Sustentabilidad, A.C., Villahermosa, Mexico
Centro Transdiciplinar Universitario para la Sustentabiliad, Universidad Iberoamericana, Mexico City, Mexico
Univ Nacl Autonoma Mexico, Fac Ciencias, Dept Ecol & Recursos Nat, Mexico City, DF, Mexico
Ctr Cambio Global & Sustentabilidad AC, Villahermosa, Mexico
Univ Iberoamer, Ctr Transdiciplinar Univ Sustentabiliad, Mexico City, DF, Mexico
|