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Developmental plasticity is the capacity of a single genotype to express multiple phenotypes in response to different early‐life environments. Such responses are defined by reaction norms, which may vary among individuals or populations. Variation in developmental reaction norms allows natural selection to operate on plasticity and is rarely examined in vertebrates. We quantified variation in embryonic developmental plasticity within and between populations using the brown anole lizard. We captured lizards from two islands in the Matanzas River (Florida, USA) and incubated their eggs under one of two multivariate treatments that mimicked the temperature, moisture and substrates of nest sites in either a shaded or open habitat. We measured hatchling morphology, performance, and physiology to quantify variation in family‐level reaction norms. We observed evidence of family‐level variation in reaction norms for morphology but not for performance or physiology, indicating an opportunity for natural selection to shape plasticity in hatchling body size. Overall, the results indicate that multiple abiotic conditions in natural nests combine to increase or reduce phenotypic variation, and that family‐level variation in reaction norms provides a potential for natural selection to shape plasticity.
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Natural nest substrates influence squamate embryo physiology but have little effect on hatchling phenotypes
Abstract Vertebrate embryos require access to water; however, many species nest in terrestrial habitats that vary considerably in moisture content. Oviparous, non‐avian reptiles have served as models to understand how environmental factors, like moisture availability, influence development because eggs are often exposed to prevailing environments in the absence of parental care. Though much research demonstrates the importance of water absorption by eggs, many ecological factors that influence moisture availability in natural nests have received little attention. For example, the type of substrate in which nests are constructed is understudied. We experimentally incubated eggs of the brown anole lizard (Anolis sagrei) in 2 naturally occurring nest substrates that were treated with varying amounts of water to determine how natural substrates influence development at different moisture concentrations. One substrate consisted of sand and crushed seashells and the other was mostly organic material (i.e. decayed plant material). Both are common nesting substrates at our field site. When controlling for water uptake by eggs, we found that egg survival and hatchling phenotypes were similar between substrates; however, embryos developed more quickly in the sand/shell substrate than the organic substrate, indicating substrate‐specific effects on embryo physiology. These results demonstrate that different natural substrates can result in similar developmental outcomes if the water available to eggs is comparable; however, some aspects of development, like developmental rate, are affected by the type of substrate, independent of water availability. Further study is required to determine how natural substrates influence embryo physiology independent of water content.
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- Award ID(s):
- 1942145
- PAR ID:
- 10369790
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Integrative Zoology
- Volume:
- 17
- Issue:
- 4
- ISSN:
- 1749-4877
- Page Range / eLocation ID:
- p. 550-566
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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