Community‐wide seasonal shifts in thermal tolerances of mosquitoes

Abstract

The broadening in species’ thermal tolerance limits and breadth from tropical to temperate latitudes is proposed to reflect spatial gradients in temperature seasonality, but the importance of seasonal shifts in thermal tolerances within and across locations is much less appreciated. We performed thermal assays to examine the maximum and minimum critical temperatures (CTmax and CTmin, respectively) of a mosquito community across their active seasons. Mosquito CTmin tracked seasonal shifts in temperature, whereas CTmax tracked a countergradient pattern with lowest heat tolerances in summer. Mosquito thermal breadth decreased from spring to summer and then increased from summer to autumn. We show a temporal dichotomy in thermal tolerances with thermal breadths of temperate organisms in summer reflecting those of the tropics (“tropicalization”) that is sandwiched between a spring and autumn “temperatization.” Therefore, our tolerance patterns at a single temperate latitude recapitulate classical patterns across latitude. These findings highlight the need to understand the temporal and spatial components of thermotolerance variation better, including plasticity and rapid seasonal selection, and the potential for this variation to affect species responses to climate change. With summers becoming longer and increasing winter nighttime temperatures, we expect increasing tropicalization of species thermal tolerances in both space and time.

Heat tolerance variation reveals vulnerability of tropical herbivore–parasitoid interactions to climate change

“…microclimate selection) might be the main strategy to cope with the heat, and to buffer selection pressure for physiological tolerance (Huey et al, 2003;Wenda et al, 2021). The lower CTmax in canopy species we found may represent more dependence on behavioural thermoregulation, which could not be accounted for in laboratory-based CTmax experiments (Hodgson & Schwanz, 2019;Oliveira et al, 2021).…”

“…forest canopies) which often have higher CTmax compared to ectotherms from cooler environments, showing low phylogenetic conservation (i.e. phylogenetic signal) (Baudier et al, 2015;Duarte et al, 2012;García-Robledo et al, 2016;Leahy et al, 2022;Oliveira et al, 2021). CTmax, can also be influenced by intrinsic organismal characteristics such as body size (Gillooly et al, 2001).…”

Mosquito thermal tolerance is remarkably constrained across a large climatic range

“…Given this, Ae. sierrensis appears to have substantially lower warming tolerance (the difference between CT ୫ୟ୶ and habitat temperature) than related mosquito species 52 and other mid-latitude ectotherms 3 , suggesting it may be particularly vulnerable to additional warming. However, juvenile Ae.…”

Assessing the role of family level variation and heat shock gene expression in the thermal stress response of the mosquito Aedes aegypti

“…Several of these chaperones appear to be co-opted by DENV to assist with its replication inside mosquito cells [49,50]. Specifically, HSP90 and HSP70 have both been shown to assist with infection of human and mosquito cells for multiple mosquito-transmitted viruses [36][37][38]51,52].…”

“…mosquito specific fitness traits quantified over a range of ambient environmental temperatures) varies across global landscapes [ 6 , 16 , 34 , 35 ] and through time (i.e. seasonality) [ 36 ].…”