Geographic variation in thermal physiological performance of the intertidal crabPetrolisthes violaceusalong a latitudinal gradient

Abstract

Environmental temperature has profound effects on the biological performance and biogeographical distribution of ectothermic species. Variation of this abiotic factor across geographic gradients is expected to produce physiological differentiation and local adaptation of natural populations depending on their thermal tolerances and physiological sensitivities. Here, we studied geographic variation in whole-organism thermal physiology of seven populations of the porcelain crab Petrolisthes violaceus across a latitudinal gradient of 3000 km, characterized by a cline of thermal conditions. Our study found that populations of P. violaceus show no differences in the limits of their thermal performance curves and demonstrate a negative correlation of their optimal temperatures with latitude. Additionally, our findings show that high-latitude populations of P. violaceus exhibit broader thermal tolerances, which is consistent with the climatic variability hypothesis. Interestingly, under a future scenario of warming oceans, the thermal safety margins of P. violaceus indicate that lower latitude populations can physiologically tolerate the ocean-warming scenarios projected by the IPCC for the end of the twenty-first century.

Phenotypic plasticity at the edge: Contrasting population‐level responses at the overlap of the leading and rear edges of the geographical distribution of two Scurria limpets

“…These results are an extension of earlier findings showing that altitudinal persistence of tropical or montane species is compromised by narrow thermal safety margins (Huey et al., ; Sunday et al., ). Namely, populations of S. viridula that maintain their aerobic capacity at warmer temperatures are expected to have higher thermal tolerance and are predicted to persist longer than populations that experienced a decline in aerobic performance as temperature increases, like S. zebrina (Gaitán‐Espitía et al., ). Our results allow us to extend the thermal safety margin hypothesis to populations at the rear edge of the range, which reach higher temperatures only by compromising their thermal safety margin, something that is also suggested by the μ max .…”

“…For extreme temperatures of the thermal treatment (−2 to 6°C and 26–38°C), HR was measured every 1°C, whereas for intermediate temperatures (6–26°C) it was measured every 2°C. HR was estimated using an AMP 03 heartbeat amplifier (Newshift Ltd ® ) connected to an oscilloscope and the results were expressed in beats per min −1 (Gaitán‐Espitia et al., ). Measurements of aerial cardiac activity were performed at the same period of the day to cancel the effects of a possible circadian or tidal rhythm of respiration.…”

Biological responses to environmental heterogeneity under future ocean conditions

“…Gaitán‐Espitia et al . () reported the influence of greater thermal variability at higher latitudes on the plasticity of responses in thermal physiology of porcelain crabs. Molina‐Montenegro & Naya () advocated that the CVH could be a powerful conceptual framework with which to view the impact of future climate change on species persistence and phenotypic plasticity.…”

Biologging Physiological and Ecological Responses to Climatic Variation: New Tools for the Climate Change Era

“…Heart rate predicts the thermal dependence of metabolism better than activity (Clark et al, 2010), suggesting a role for additional sensors in understanding how thermal limits and performance influence range shifts. Additionally, biologgers may play a crucial role in quantifying changes in thermal performance through acclimatization (i.e., physiological flexibility) and/or developmental plasticity, as well as documenting genetic variation in thermal performance (Kingsolver, 2009;Gaitán-Espitia et al, 2014), which are key aspects of population and species resilience to environmental change (Somero, 2010;Seebacher et al, 2015).…”