Latitudinal comparison of thermotolerance and HSP70 production in F2 larvae of the Greenshell mussel (Perna canaliculus)

Abstract

SUMMARYWe report the first measures of thermotolerance (recorded as percentage mortality and induced HSP70 production) for pelagic larvae of three populations of the New Zealand greenshell (green-lipped) mussel Perna canaliculus. Our goal was to determine whether distinct populations of P. canaliculus were more susceptible to predicted climate change than others, and whether such patterns of susceptibility were either genetically controlled (local adaptation of populations) or simply reflect the acclimatory capacity of this species. F2 larvae from three P. canaliculus populations (DʼUrville Island, Banks Peninsula and Stewart Island) were subjected to an acute thermal challenge (3h exposure to a fixed temperature in the range 20-42°C). No latitudinal patterns in either percentage mortality or HSP70 protein production were apparent. For all populations, larval mortality (LT 50 ) was between 32.9 and 33.9°C, with significant amounts of HSP70 induction only occurring in those individuals that experienced temperatures of 40°C or greater. The data presented therefore do not support the hypothesis that genetic adaptation of P. canaliculus to distinct thermal environments will be reflected by a corresponding difference in acute heat tolerance. In fact, the apparently vulnerable veligers show a surprisingly wide thermal safety margin. To develop a comprehensive understanding of the effects of ocean warming upon this species, subsequent studies should consider the impacts of sub-lethal stress upon fitness in addition to chronic thermal challenge and, crucially, the response of sedentary juvenile and adult stages.

Integrating within-species variation in thermal physiology into climate change ecology

“…Scytothalia displays strong patterns of local adaptation in its upper thermal limits along a latitudinal climate gradient [13] that is thought to be driven, in part, by limited gene flow between populations as a result of its large propagule size and a negatively buoyant thallus [38]. By contrast, many invertebrate and vertebrate species produce motile larvae with long pelagic larval phases which can facilitate gene flow, thereby helping to homogenize thermal limits between populations [39]. Long-distance dispersal can also occur in seaweeds [40] and is not ubiquitous within marine animals.…”

Adaptive Responses of Marine Gastropods to Heatwaves

“…EM1137), which has been validated for marine mollusks. [53][54][55] TAC and MDA concentration were determined using the assay kits purchased from Nanjing Jiancheng Bioengineering Institute, China (catalog no. A015-1 and A003-1, respectively).…”

Emersion and Relative Humidity Modulate Stress Response and Recovery Dynamics in Juvenile Mussels (Perna canaliculus)

“…Complex, multi-species mussel guilds occupy the New Zealand rocky shore, with lower-littoral Perna canaliculus giving way to Mytilus , Aulacomya and Xenostrobus species on the higher shore [ 35 , 57 ]. Thermotolerance has been demonstrated to be a key determinant of this vertical zonation [ 57 ], which is turn likely to be influenced by region, latitude and genetic structure [ 58 ]. Based on the findings presented here, it would be valuable to consider the role of juvenile emersion and, in particular, reoxygenation stress as factors influencing natural distribution in an increasingly marine heatwave-prone region [ 59 ].…”