Populations at the edge of their species' distribution ranges are typically living at the physiological extreme of the environmental conditions they can tolerate. As a species' response to global change is likely to be largely determined by its physiological performance, subsequent changes in environmental conditions can profoundly influence populations at range edges, resulting in range extensions or retractions. To understand the differential physiological performance among populations at their distribution range edge and center, we measured levels of mRNA for heat shock protein 70 (hsp70) as an indicator of temperature sensitivity in two high-shore littorinid snails, Echinolittorina malaccana and E. radiata, between 1 degrees N to 36 degrees N along the NW Pacific coast. These Echinolittorina snails are extremely heat-tolerant and frequently experience environmental temperatures in excess of 55 degrees C when emersed. It was assumed that animals exhibiting high temperature sensitivity will synthesize higher levels of mRNA, which will thus lead to higher energetic costs for thermal defense. Populations showed significant geographic variation in temperature sensitivity along their range. Snails at the northern range edge of E. malaccana and southern range edge of E. radiata exhibited higher levels of hsp70 expression than individuals collected from populations at the center of their respective ranges. The high levels of hsp70 mRNA in populations at the edge of a species' distribution range may serve as an adaptive response to locally stressful thermal environments, suggesting populations at the edge of their distribution range are potentially more sensitive to future global warming. (c) 2018 Elsevier B.V. All rights reserved.
1.Xiamen Univ, State Key Lab Marine Environm Sci, Coll Ocean & Earth Sci, Xiamen 361102, Peoples R China 2.Univ Hong Kong, Swire Inst Marine Sci, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China 3.Univ Hong Kong, Sch Biol Sci, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China 4.King Mongkuts Inst Technol Ladkrabang, Fac Agr Technol, Bangkok 10520, Thailand 5.Acad Sinica, Res Ctr Biodivers, Taipei 115, Taiwan 6.Natl Univ Malaysia, Marine Ecosyst Res Ctr, Ukm Bangi 43600, Malaysia 7.SFAlut Sdn Bhd, B-11-1,Viva Bldg 378,Jalan Ipoh, Kuala Lumpur 51200, Malaysia 8.James Cook Univ Singapore, TropWATER Ctr Trop Water & Aquat Ecosyst Res, 149 Sims Dr, Singapore 387380, Singapore
Recommended Citation:
Han, Guo-dong,Cartwright, Stephen R.,Ganmanee, Monthon,et al. High thermal stress responses of Echinolittorina snails at their range edge predict population vulnerability to future warming[J]. SCIENCE OF THE TOTAL ENVIRONMENT,2019-01-01,647:763-771