Phenotypic effects of thermal mean and fluctuations on embryonic development and hatchling traits in a lacertid lizard, Takydromus septentrionalis

✍ Scribed by Wei-Guo Du; Jia-Hua Feng

• Publisher: Wiley (John Wiley & Sons)
• Year: 2008
• Tongue: English
• Weight: 145 KB
• Volume: 309A
• Category: Article
• ISSN: 1932-5223
• DOI: 10.1002/jez.442

✦ Synopsis

Abstract

How fluctuating temperatures influence reptilian embryos and hatchlings has attracted increasing scientific attention, but is poorly known. We conducted an incubation experiment with a factorial design of two mean temperatures (24 vs. 28°C) and three diel thermal fluctuations (0, ±3, ±6°C) to determine the effects of diel thermal fluctuations and mean temperature on incubation duration and hatchling phenotypes. Both diel thermal fluctuations and mean temperature significantly affected incubation duration, but not hatching success. Incubation duration increased with increasing temperature fluctuations at a mean temperature of 24°C, but not at a mean temperature of 28°C. The significant interaction between diel thermal fluctuations and mean temperature on hatchling morphology indicated that the effect of thermal fluctuations depended on the mean temperature. Hatchling mass differed significantly between 24±6 and 28±6°C, but not between the two constant temperatures or the temperatures with ±3°C fluctuations. At a mean temperature of 24°C, the effect of thermal fluctuations on hatchling size was marginally significant, with relatively large hatchlings at the constant temperature; at a mean temperature of 28°C, thermal fluctuations had no impact on hatchling size. The locomotor performances were significantly affected by mean temperature rather than diel thermal fluctuations. Therefore, diel thermal fluctuations around a given mean temperature do not affect hatchling phenotypes in a relatively large magnitude, but the influence of diel thermal fluctuations may differ with changing mean temperatures. J. Exp. Zool. 309A:138–146, 2008. © 2008 Wiley‐Liss, Inc.