- Publication Date:
- NSF-PAR ID:
- Journal Name:
- Proceedings of the Royal Society B: Biological Sciences
- Sponsoring Org:
- National Science Foundation
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Cooke, Steve (Ed.)Abstract Models of species response to climate change often assume that physiological traits are invariant across populations. Neglecting potential intraspecific variation may overlook the possibility that some populations are more resilient or susceptible than others, creating inaccurate predictions of climate impacts. In addition, phenotypic plasticity can contribute to trait variation and may mediate sensitivity to climate. Quantifying such forms of intraspecific variation can improve our understanding of how climate can affect ecologically important species, such as invasive predators. Here, we quantified thermal performance (tolerance, acclimation capacity, developmental traits) across seven populations of the predatory marine snail (Urosalpinx cinerea) from native Atlantic and non-native Pacific coast populations in the USA. Using common garden experiments, we assessed the effects of source population and developmental acclimation on thermal tolerance and developmental traits of F1 snails. We then estimated climate sensitivity by calculating warming tolerance (thermal tolerance − habitat temperature), using field environmental data. We report that low-latitude populations had greater thermal tolerance than their high latitude counterparts. However, these same low-latitude populations exhibited decreased thermal tolerance when exposed to environmentally realistic higher acclimation temperatures. Low-latitude native populations had the greatest climate sensitivity (habitat temperatures near thermal limits). In contrast, invasive Pacific snails had the lowestmore »
Integrating patterns of thermal tolerance and phenotypic plasticity with population genetics to improve understanding of vulnerability to warming in a widespread copepod
Differences in population vulnerability to warming are defined by spatial patterns in thermal adaptation. These patterns may be driven by natural selection over spatial environmental gradients, but can also be shaped by gene flow, especially in marine taxa with high dispersal potential. Understanding and predicting organismal responses to warming requires disentangling the opposing effects of selection and gene flow. We begin by documenting genetic divergence of thermal tolerance and developmental phenotypic plasticity. Ten populations of the widespread copepod
Acartia tonsawere collected from sites across a large thermal gradient, ranging from the Florida Keys to Northern New Brunswick, Canada (spanning over 20° latitude). Thermal performance curves (TPCs) from common garden experiments revealed local adaptation at the sampling range extremes, with thermal tolerance increasing at low latitudes and decreasing at high latitudes. The opposite pattern was observed in phenotypic plasticity, which was strongest at high latitudes. No relationship was observed between phenotypic plasticity and environmental variables. Instead, the results are consistent with the hypothesis of a trade‐off between thermal tolerance and the strength of phenotypic plasticity. Over a large portion of the sampled range, however, we observed a remarkable lack of differentiation of TPCs. To examine whether this lack of divergence ismore »
Environmental predictability drives adaptive within‐ and transgenerational plasticity of heat tolerance across life stages and climatic regions
Although environmental variability and predictability have been proposed as the underlying ecological context in which transgenerational plasticity (
TGP) arises, the adaptive significance and interaction with within‐generation plasticity ( WGP) in such scenarios is still poorly understood. To investigate these questions, we considered the tolerance to upper thermal limits of larvae and adults of the desert endemic Drosophila mojavensisadapted to different climatic regions (Desert vs. Mediterranean climate).
Thermal plasticity was investigated by acclimating parents and offspring at 36°C (vs. at 25°C). We then used historical temperature variation data from both regions to perform individual‐based simulations by modelling expected components of adaptive plasticity in multiple life stages.
Our results indicated that thermal response to ramping heat shocks was more pronounced in larvae, where acclimation treatments in parents and offspring increased their heat‐shock performance, while heat knockdown in adults was only increased by offspring acclimation of adults. The relative contribution of
WGPand TGPwas greater for the population from the more thermally variable Sonoran Desert.
Similarly, individual‐based simulations of evolving maternal effects indicated that variation in tolerance to upper thermal limits across life stages and climates is expected from its adaptive significance in response to environmental predictability.
Our approach offers a new perspective and interpretation of adaptive plasticity, demonstrating that environmentalmore »
Plain Language Summarycan be found within the Supporting Information of this article.
Analyses of heat tolerance in insects often suggest that this trait is relatively invariant, leading to the use of fixed thermal maxima in models predicting future distribution of species in a warming world. Seasonal environments expose populations to a wide annual temperature variation. To evaluate the simplifying assumption of invariant thermal maxima, we quantified heat tolerance of 26 ant species across three seasons that vary two‐fold in mean temperature. Our ultimate goal was to test the hypothesis that heat tolerance tracks monthly temperature. Ant foragers tested at the end of the summer, in September, had higher average critical thermal maximum (CTmax) compared to those in March and December. Four out of five seasonal generalists, species actively foraging in all three focal months, had, on average, 6°C higher CTmaxin September. The invasive fire ant,
Solenopsis invicta, was among the thermally plastic species, but the native thermal specialists still maintained higher CTmaxthan S. invicta. Our study shows that heat tolerance can be plastic, and this should be considered when examining species‐level adaptations. Moreover, the plasticity of thermal traits, while potentially costly, may also generate a competitive advantage over species with fixed traits and promote resilience to climate change.
By the century's end, many tropical seas will reach temperatures exceeding most coral species' thermal tolerance on an annual basis. The persistence of corals in these regions will, therefore, depend on their abilities to tolerate recurrent thermal stress. Although ecologists have long recognized that positive interspecific interactions can ameliorate environmental stress to expand the realized niche of plants and animals, coral bleaching studies have largely overlooked how interactions with community members outside of the coral holobiont shape the bleaching response. Here, we subjected a common coral,
Pocillopora grandis, to 10 days of thermal stress in aquaria with and without the damselfish Dascyllus flavicaudus(yellowtail dascyllus), which commonly shelter within these corals, to examine how interactions with damselfish impacted coral thermal tolerance. Corals often benefit from nutrients excreted by animals they interact with and prior to thermal stress, corals grown with damselfish showed improved photophysiology ( Fv/ Fm) and developed larger endosymbiont populations. When exposed to thermal stress, corals with fish performed as well as control corals maintained at ambient temperatures without fish. In contrast, corals exposed to thermal stress without fish experienced photophysiological impairment, a more than 50% decline in endosymbiont density, and a 36% decrease in tissue protein content. At the end of themore »