Linking behaviour and climate change in intertidal ectotherms: insights from littorinid snails

Abstract

22A key element missing from many predictive models of the impacts of climate change 23 on intertidal ectotherms is the role of individual behaviour. In this synthesis, using 24 littorinid snails as a case study, we show how thermoregulatory behaviours may 25 buffer changes in environmental temperatures. These behaviours include either a 26 flight response, to escape the most extreme conditions and utilize warmer or cooler 27 environments; or a fight response, where individuals modify their own environments 28 to minimize thermal extremes. A conceptual model, generated from studies of 29 littorinid snails, shows that various flight and fight thermoregulatory behaviours may 30 allow an individual to widen its thermal safety margin (TSM) under warming or 31 cooling environmental conditions and hence increase species' resilience to climate 32 change. Thermoregulatory behaviours may also buffer sublethal fitness impacts 33 associated with thermal stresses. Through this synthesis, we emphasise that future 34 studies need to consider not only animals' physiological limits but also their capacities 35 to buffer the impact of climate change through behavioural responses. Current 36 generalizations, made largely on physiological limits of species, often neglect the 37 buffering effects of behaviour and may, therefore, provide an over-estimation of 38 vulnerability, and consequently poor prediction of the potential impacts of climate 39 change on intertidal ectotherms. 40 41

Notes from a snail island: Littorinid evolution and adaptation

“…Research on thermal adaptation and resilience to environmental change has focused heavily on rocky intertidal species because they occur close to the limits of their thermal tolerance (Helmuth et al., ) and are regularly exposed to desiccation by tidal action (Monaco, McQuaid & Marshall, ). Given their widespread distribution, Littorinids have also been established as a model system for studying environmental stress, with particular focus on species in tropical regions, where adapting to extreme temperatures is a necessity for survival (Ng et al., ). A good contingent of researchers working on these questions was also present at the ISOLBE meeting.…”

“…For Echinolittorina species, thermal tolerances peak at surface temperatures of around 50°C in the laboratory (Dong, Liao, Meng & Somero, ), but real temperatures on the shore often greatly exceed this—surfaces reach up to 62°C in the height of summer on Hong Kong rocky shores, for example. To cope with this extreme threat to survival, Echinolittorina (and other intertidal species) often use behavioural adaptations to exploit high‐temperature refuges (Ng et al., ). For example, both E. malaccana and E. radiata snails use standing and towering behaviour to lift themselves off the warm rock and reduce their body temperature (Figure b; Seuront & Ng, ).…”

“…Desiccation will limit behaviour due to water loss before thermal tolerance limits are reached—which means that the optimal temperature ranges for behaviours such as foraging will differ from physiological responses important for survival (Monaco et al., ). Extreme stress may therefore lead to a decoupling of tolerance curves as an adaptation and should be taken into account when considering how animals will evolve in the face of climate change (Ng et al., ); there is clearly a need to study multiple traits and stressors rather than a single one. This represents an opportunity to study thermal adaptation in the context of speciation, as mismatch between tolerance and ecology or morphology in hybrids will act as a barrier to gene flow (Vinšálková & Gvoždik ).…”

Mapping microhabitat thermal patterns in artificial breakwaters: Alteration of intertidal biodiversity by higher rock temperature

“…The spatial homogeneity which characterizes artificial infrastructures can, therefore, impose a great challenge for intertidal species that live in these habitats (Chapman, , , ), which have developed a suite of behavioral strategies like aggregation, that is, either inside or outside crevices (Aguilera & Navarrete, ; Cartwright & Williams, ; Chapperon & Seuront, , ; Garrity, ; Harper & Williams, ; Moreira, Chapman, & Underwood, ), aggregating towering and mushrooming (Ng et al, ; Williams et al, ), sun orientation shell movement (Muñoz, Randall Finke, Camus, & Bozinovic, ), adopt sloping or vertical shaded habitats (Lima et al, ; Miller, Harley, & Denny, ), or take refuge underneath boulders (Liversage, ) to cope with wave and thermal stress. This lack of suitable habitat heterogeneity seems especially relevant in artificial breakwaters made of granite boulders or “rip‐raps” which, despite their reduced small‐scale (few cms) spatial heterogeneity, have increased structural complexity at larger scales (tens of meters).…”

Structural traits dictate abiotic stress amelioration by intertidal oysters

“…Increasing environmental temperatures directly influence the body temperatures of ectotherms, modifying their physiological performance and vulnerability to other stressors (Huey et al, 2012;Stevenson, 1985). Although warming may benefit some ectotherms (e.g., basking in lizards, Angilletta, Niewiarowski, & Navas, 2002;Gunderson & Leal, 2012), increased warming challenges the survival of many species, with species' persistence dependent on physiological or behavioural adaptations, especially in physically harsh environments such as the tropics (Ng et al, 2017;Somero, 2010;Tewksbury, Huey, & Deutsch, 2008).…”