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Abstract Theory predicts that thermal developmental plasticity evolves in response to thermal heterogeneity, suggesting that plasticity may be an important trait for establishment in novel climates. However, few studies use multispecies comparisons to examine how plasticity evolves, meaning that there is little empirical basis with which to examine key theoretical predictions. We estimate patterns of thermal developmental plasticity in morphological and performance traits for 7 Anolis lizard species inhabiting South Florida, USA. We found interspecific differences as well as intraspecific variation in reaction norms across species. Neither temperature heterogeneity in present-day invasive ranges in Florida nor historical temperature heterogeneity from the contemporary native ranges predicted reaction norm variation. Phylogeny and species identity typically predicted around 90%–95% of reaction norm variation. Overall, these results suggest that thermal developmental plasticity in these traits exhibits variation that could be inconsistent with patterns expected under adaptive evolution to macroclimate. Examining the role of maternal nesting behavior and sampling of additional species can help to distinguish between neutral variation and selection toward multiple adaptive peaks. Our comparative study of thermal developmental plasticity in lizards provides new insights about macroevolutionary dynamics behind the evolution of developmental plasticity and the conditions under which adaptive plasticity is expected to evolve.
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Variability approaching the thermal limits can drive diatom community dynamics
Abstract Organismal distributions are largely mediated by temperature, suggesting thermal trait variability plays a key role in defining species' niches. We employed a trait‐based approach to better understand how inter‐ and intraspecific thermal trait variability could explain diatom community dynamics using 24 strains from 5 species in the diatom genusSkeletonema, isolated from Narragansett Bay (NBay), where this genus can comprise up to 99% of the microplankton. Strain‐specific thermal reaction norms were generated using growth rates obtained at temperatures ranging from −2°C to 36°C. Comparison of thermal reaction norms revealed inter‐ and intraspecific similarities in the thermal optima, but significant differences approaching the thermal limits. Cellular elemental composition was determined for two thermally differentiated species and again, the most variation occurred approaching the thermal limits. To determine the potential impact of interspecific variability on community composition, a species succession model was formulated utilizing each species' empirically determined thermal reaction norm and historical temperature data from NBay. Seasonal succession in the modeled community resembled the timing of species occurrence in the field, but not species' relative abundance. The model correctly predicted the timing of the dominant winter–spring species,Skeletonema marinoi, within 0–14 d of its observed peak occurrence in the field. Interspecific variability approaching the thermal limits provides an alternative mechanism for temporal diatom succession, leads to altered cellular elemental composition, and thus has the potential to influence carbon flux and nutrient cycling, suggesting that growth approaching the thermal limits be incorporated into both empirical and modeling efforts in the future.
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- PAR ID:
- 10456833
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Limnology and Oceanography
- Volume:
- 65
- Issue:
- 9
- ISSN:
- 0024-3590
- Page Range / eLocation ID:
- p. 1961-1973
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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