Phenotypic evidence for local adaptation to heat stress in the marine snail Chlorostoma (formerly Tegula) funebralis

Abstract

Southern California (USA) populations of the intertidal marine snailChlorostoma (formerly Tegula) funebralis generally occupy warmer climates and are exposed to high air temperatures during low tides more often than northern California populations. Available genetic data suggest there is extensive gene flow across a broad range of C. funebralis populations, so it is unclear if populations can adapt to differences in local environments. To test for population-specific responses to heat stress, three phenotypic assays were performed on three northern and on three southern populations of C. funebralis, after acclimation to common-garden conditions in the laboratory.Thermal drop-down, heat stress mortality, and heat stress reattachment assays were designed to evaluate ecologically relevant phenotypic responses to heat stress; these assays assessed tolerance during, mortality following, and speed of recovery following heat stress. The latter two tests indicate that southern populations consistently suffer significantly lower mortality and recover significantly more quickly following heat stress compared to northern populations. Hierarchical cluster analysis of stress response data clearly identified northern California and southern California regional groupings of populations. Thus, these results indicate that southern populations have higher tolerance to heat stress than northern populations and suggest that adaptation to local environmental differences can evolve despite moderate potential for larval dispersal in this species. Accounting for intraspecific population variation in thermal tolerance may provide important insights for predicting how species distributions will respond to global warming.al., 2010) and that adaptive differentiation often occurs in species with planktonic dispersal (Sanford and Kelly, 2010), local adaptation in the sea remains understudied. As rates of environmental change are accelerating

RNA‐seq reveals regional differences in transcriptome response to heat stress in the marine snail Chlorostoma funebralis

“…), few have investigated genetically based population differences in thermal tolerance (but see Kuo & Sanford ; Willett ; Schoville et al . ; Gleason & Burton ).…”

“…Across this large latitudinal range, populations experience significantly different maximum, minimum, and average air and water temperatures (National Oceanographic Data Center, NOAA Satellite and Information Service). Gleason & Burton () demonstrated that northern and southern California populations differ significantly in thermal tolerance, with three southern populations consistently suffering significantly lower mortality and recovering significantly more quickly following heat stress compared with three northern populations. However, the molecular mechanisms underlying these differential tolerances have not been investigated.…”

“…Where such differences occur, insight into the underlying mechanisms is key to better predict how species will respond to global warming; whether plasticity or local adaptation is responsible for population-specific thermal tolerances will affect populations' vulnerability to local extinction (Sanford & Kelly 2011). Although numerous studies have examined the role of transcriptional phenotypic plasticity on temperature response in marine organisms (Sorte & Hofmann 2004;Zippay & Hofmann 2010;Jimenez-Melero et al 2012;Massamba-N'Siala et al 2012;Smith et al 2013), few have investigated genetically based population differences in thermal tolerance (but see Kuo & Sanford 2009;Willett 2010;Schoville et al 2012;Gleason & Burton 2013).…”

Reference gene selection for quantitative gene expression studies during biological invasions: A test on multiple genes and tissues in a model ascidian Ciona savignyi

“…Among many factors such as behavioral, biochemical, physiological, and genetic/epigenetic ones (Boyko and Kovalchuk, 2008;Gleason and Burton, 2013), gene expression changes represent one crucial mechanism for species to cope with environmental stressors during biological invasions (de Nadal et al, 2011). For instance, the transcriptional expression of individual candidate genes (such as the heat shock protein 70 gene) showed different patterns between invasive and native species in response to heat stress, suggesting that a higher level of heat tolerance of invasive species might contribute to their invasion success (Henkel and Hofmann, 2007;Zerebecki and Sorte, 2011).…”

A dynamic oceanographic front drives biogeographical structure in invertebrate settlement along Santa Cruz Island, California, USA

“…Changes in connectivity may also have implications for management issues such as the design and placement of marine protected areas and networks since the transport of larvae between locations may be essential to maintaining populations (Strathmann et al 2002, Carr et al 2003, Morgan et al 2009). Moving boundaries could also contribute to the ability of larvae from source populations to reach sites, and since populations of marine species may differ greatly in responses to environmental factors such as temperature, movement among populations (or lack thereof) may have important repercussions for how populations respond to perturbations such as climate change (Kelly et al 2012, Sorte et al 2011, Gleason & Burton 2013.…”