Hypothesis: Phenotypic variation in traits induced by different incubation temperatures does not persist into the lifetime of young lizards, and therefore contributes little to variation in long-term fitness.
Organism: Western fence lizard (Sceloporus occidentalis).
Methods: Split-clutch laboratory incubation experiment including eggs from two different populations under two different incubation regimes, measurement of morphological traits at hatching, and tracking of morphology and temperature preference behaviour for 7 weeks after hatching.
Results: Several morphological traits, including body mass, hindlimb length, inter-limb length, and tail length, initially differed between the two incubation treatments, but only the difference in tail length persisted to age 7 weeks. Thermal preference was relatively conserved, with juveniles showing no difference in mean selected body temperatures across treatments; however, warm-incubated lizards thermoregulated more precisely than their cool-incubated counterparts.
Conclusion: Studies of incubation effects can reveal changes in animal phenotypes post-hatching, but if these effects do not persist, they may not be subject to natural selection and consequently be of little ecological relevance.
© 2007 Stephen C. Adolph
Buckley, C. R., M. Jackson, M. Youssef, D. J. Irschick, and S. C. Adolph. "Testing the persistence of phenotypic plasticity after incubation in the Western fence lizard, Sceloporus occidentalis." Evolutionary Ecology Research 9.1 (2007): 169-183.