Terrestrial insects and climate change: adaptive responses in key traits

Abstract

Understanding and predicting how adaptation will contribute to species' resilience to climate change will be paramount to successfully managing biodiversity for conservation, agriculture, and human health‐related purposes. Making predictions that capture how species will respond to climate change requires an understanding of how key traits and environmental drivers interact to shape fitness in a changing world. Current trait‐based models suggest that low‐ to mid‐latitude populations will be most at risk, although these models focus on upper thermal limits, which may not be the most important trait driving species' distributions and fitness under climate change. In this review, we discuss how different traits (stress, fitness and phenology) might contribute and interact to shape insect responses to climate change. We examine the potential for adaptive genetic and plastic responses in these key traits and show that, although there is evidence of range shifts and trait changes, explicit consideration of what underpins these changes, be that genetic or plastic responses, is largely missing. Despite little empirical evidence for adaptive shifts, incorporating adaptation into models of climate change resilience is essential for predicting how species will respond under climate change. We are making some headway, although more data are needed, especially from taxonomic groups outside of Drosophila, and across diverse geographical regions. Climate change responses are likely to be complex, and such complexity will be difficult to capture in laboratory experiments. Moving towards well designed field experiments would allow us to not only capture this complexity, but also study more diverse species.

Insect responses to heat: physiological mechanisms, evolution and ecological implications in a warming world

“…Current evidence suggests that plastic responses of insects to heat are limited and may not be sufficient to withstand ongoing warming trends (Gunderson & Stillman, ; Kellermann & Sgrò, ). Furthermore, although important for rapid responses to sudden climate changes, plasticity has not yet been linked to sustained responses with fitness benefits across generations in insects (Kellermann & van Heerwaarden, ; Radchuk et al ., ). In fact, plasticity could even hinder adaptive responses to climate change, as shown for the butterfly Bicyclus anynana , where seasonal plasticity is related to gene expression variation instead of intra‐population genetic variation for plasticity, thus limiting the potential for adaptive responses (Oostra et al ., ).…”

“…However, when temperature was experimentally increased at a rate of 0.3°C per generation, D. melanogaster heat tolerance did not increase even after 20 generations, indicating low evolutionary potential in this trait (Schou et al ., ). Indeed, selection plateaus for heat tolerance have often been described for D. melanogaster (Kellermann & van Heerwaarden, ) and comparative evidence across the genus Drosophila suggests that adaptation to heat is actually slow and has little potential to protect species that already live close to their upper thermal limits (Sørensen et al ., ). Also, it is important to note that, given their dependence on factors specific to the considered populations (e.g.…”

Insects and recent climate change

“…Nevertheless, considering results from the studies in Table 1 along with spatial or occupancy surveys (e.g., 18), conclusions do emerge. Ongoing climate change will have positive effects on some species and negative effects on others (54, 55), with the balance (of positive and negative effects) determined in some cases by geographic factors such as latitudinal position (20, 37) and in other cases by more complex species-specific traits (6, 7), as in the Northern California case study (Fig. 2).…”

Heat tolerance and acclimation capacity in subterranean arthropods living under common and stable thermal conditions

“…Similarly, species from stable environments are predicted to have a lower thermal acclimation capacity than those from more variable habitats (e.g., Feder, ; Markle & Kozak, ; Shah, Funk, & Ghalambor, ; Tomanek, and references herein). As an extreme example, some Antarctic cold‐stenothermal species (e.g., Clark, Fraser, Burns, & Peck, ; Clark Fraser & Peck, ; La Terza, Papa, Miceli, & Luporini, ; Rinehart et al, ; Somero, ) as well as warm stenothermal coral reef fishes (Kassahn et al, ; Nilsson, Östlund‐Nilsson, & Munday, ) have lost the ability to activate a heat shock response via the expression of heat shock proteins, which makes them especially vulnerable to global change (Kellermann & van Heerwaarden, ; Patarnello, Verde, Prisco, Bargelloni, & Zane, ; Somero, ). These questions remain poorly explored in other extremely thermally stable habitats, such as subterranean environments, although some recent studies have found support for the climatic variability hypotheses for cave springtails (Raschmanová, Šustr, Kováč, Parimuchová, & Devetter, ) and spiders (Mammola, Piano, Malard, Vernon, & Isaia, ).…”