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Vol. 49 No. 3, 2010
Effects of Incubation and Rearing Temperatures on Caiman
latirostris Growth
María
Virginia Parachú Marcó1,2,*, Carlos Ignacio Piña1,2,3, Melina
Simoncini1,2, and Larriera Alejandro1,4
1Proyecto
Yacaré Laboratorio de Zoología Aplicada: Anexo Vertebrados (FHUC -
UNL/MASPyMA), A. del Valle 8700, (PC3000) Santa Fe, Argentina.
E-mail:yacare@arnet.com.ar
2CIC y TTP - CONICET, Dr. Matteri y España, (PC3105)
Diamante, Entre Ríos, Argentina
3Facultad de Ciencias y Tecnología, Universidad
Autónoma de Entre Ríos (UAdER), and Facultad de Ciencias de la
Alimentación, Universidad Nacional de Entre Ríos (UNER), Entre Ríos,
Argentina
4Facultad de Humanidades y Ciencias, Universidad
Nacional del Litoral. Secretaría de Estado de Medio Ambiente y
Desarrollo Sustentable de la Provincia de Santa Fe, Aristóbulo del
Valle 8700 - (PC3000), Santa Fe, Argentina
María
Virginia Parachú Marcó, Carlos Ignacio Piña, Melina Simoncini, and
Larriera Alejandro (2010) Different studies found that
incubation temperature has an influence on the size of Caiman
latirostris hatchlings and determines their gonadal sex.
Experimental manipulations revealed that the effects of temperature on
growth are independent of sex. Ambient temperature after hatching
is also an influential factor: juvenile caiman had lower growth at a
cool (29°C) vs. a warm temperature (33°C) independent of incubation
temperatures. Two-month-old caiman were raised at 2 different
temperatures (29 and 33°C) for 100 d. These animals were
subjected to different incubation treatments: 29, 31 (females), 33
(males), and 33°C with 17β-estradiol (females). No differences
were found in growth based on incubation temperature or sex. Our
data indicate that the evolutionary advantage of a
temperature-dependent sex determination, if it exists, is not bound to
differential growth between the sexes nor to incubation temperature, at
least in the 1st stages of life before hatchlings reach their 1st
winter. Temperatures during the development and grow-out phases
have direct effects on the size of the broad-snouted caiman.
Key words: Broad-snouted caiman, Development,
Temperature-sex determination, Estradiol
*Correspondence: E-mail:virginiapara2@yahoo.com.ar
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