Temperature variation makes an ectotherm more sensitive to global warming unless thermal evolution occurs

Abstract

1. To assess long-term impacts of global warming on species, there is growing interest in latitudinal intraspecific patterns in thermal adaptation. Yet, while both mean temperatures and daily temperature fluctuations (DTFs) are expected to increase under global warming, latitudinal differences in the effects of DTFs have not been documented.2. We tested whether low-latitude populations of an ectotherm deal better with greater DTF than high-latitude populations, especially at a high mean temperature close to the optimal temperature for growth where DTF causes exposure to extreme high temperatures. We evaluated the impact of DTFs when assessing the effect of gradual thermal evolution at the high latitude with a space-for-time substitution.3. We compared effects of both mean temperatures (20 and 24°C) and DTFs (constant = 0°C, low = 5°C and high = 10°C) on growth rates between low-latitude and high-latitude populations of the damselfly Ischnura elegans in a commongarden experiment. 4. DTFs, if anything, reduced growth and were generally stressful as indicated by reductions in body condition, antioxidant defence and metabolic rate, and increases in oxidative damage. Most negative effects of DTFs were only present at a mean of 24°C when too high temperatures were reached during a daily cycle.Notably, while 4°C warming was beneficial in terms of growth rate at both latitudes at a constant temperature regime, this changed in a negative effect at high DTF. Moreover, this modulating effect of the mean temperature by DTF differed between latitudes indicating local thermal adaptation. While 4°C warming at low DTF still caused faster growth in low-latitude larvae, it already slowed growth in high-latitude larvae. This supports the emerging insight that warming would increase growth in high-latitude larvae in the absence of DTF, yet would decrease growth in the more realistic scenarios with DTF. In contrast, a space-for-time substitution approach suggested that under gradual thermal evolution, the evolved high-latitude larvae would no longer suffer a growth reduction in the presence of DTF. 5.Our study provided important proof-of-principle that jointly integrating gradual thermal evolution and the expected increase in DTF generates opposing predictions of effects of global warming on this ectotherm. Additional supporting information may be found online in the Supporting Information section at the end of the article.How to cite this article: Verheyen J, Stoks R. Temperature variation makes an ectotherm more sensitive to global warming unless thermal evolution occurs. J Anim Ecol.

Live fast, die old: oxidative stress as a potential mediator of an unexpected life‐history evolution

“…The expected higher routine growth rates of French larvae can be explained by stronger time constraints (Dmitriew ): due to their higher number of generations per year, French larvae have less time per larval generation than the semivoltine Swedish larvae. This confirms previous results in the study species based on the same set of four populations (Stoks and De Block , Stoks et al ), as well as other sets of high‐ and low‐latitude populations (Shama et al , Debecker et al , Op de Beeck et al , Debecker and Stoks , Verheyen and Stoks ), indicating that the here documented population differences in growth rate reflect general latitudinal differences. While our design cannot completely exclude maternal effects contributing to the latitudinal pattern, we have previously shown for the study species that while size differences in eggs do exist across latitudes, they have no influence on latitudinal patterns in larval growth rates (Shama et al ).…”

“…Given that the lifespan of the study species is ca 10 days (Cordero et al ), the loss of a few days has strong fitness implications. The study species shows striking latitudinal differences in life history, with higher larval growth rates in the multivoltine (3–4 generations per year), low‐latitude populations compared to the semivoltine (2 years per generation), high‐latitude populations (Stoks and De Block , Shama et al , Stoks et al , Debecker et al , Debecker and Stoks , Van Dievel et al , Verheyen and Stoks ). Moreover, we have recently shown in separate studies that the low‐latitude populations of the species have a longer adult lifespan (reported as Supporting Information in Debecker et al ) and higher levels of antioxidant enzymes in the larval stage (Debecker and Stoks ).…”

Shrinking Body Size and Physiology Contribute to Geographic Variation and the Higher Toxicity of Pesticides in a Warming World

“…maximum DTF of 10 °C (temperatures fluctuate daily between 19 °C and 29 °C) [1][2][3] . Notably, the current thermal regime during summer in shallow ponds at the low latitude (mean of 24 °C and maximum DTF of 10 °C) corresponds to the future thermal regime predicted at the high latitude in 2100 under global warming scenario RCP 8.5 (IPCC 2013).…”

Expression Profiling of the Dof Gene Family Under Abiotic Stresses in Spinach

“…Climate change causes increasing temperature and a network of events triggering the response of plants and animals on Earth 6,7 . Although it seems that creatures on earth gradually developed local thermal adaptation, mean temperatures and daily temperature uctuations are still supposed to impact the healthy condition of each creature 8 . Spinach has cold tolerant but heat sensitive characteristics so that the plant may suffer from heat stress during its entire life with in uencing the growth of spinach plant and signi cantly decrease yield and quality 9 .…”