What Can Plasticity Contribute to Insect Responses to Climate Change?

Abstract

Plastic responses figure prominently in discussions on insect adaptation to climate change. Here we review the different types of plastic responses and whether they contribute much to adaptation. Under climate change, plastic responses involving diapause are often critical for population persistence, but key diapause responses under dry and hot conditions remain poorly understood. Climate variability can impose large fitness costs on insects showing diapause and other life cycle responses, threatening population persistence. In response to stressful climatic conditions, insects also undergo ontogenetic changes including hardening and acclimation. Environmental conditions experienced across developmental stages or by prior generations can influence hardening and acclimation, although evidence for the latter remains weak. Costs and constraints influence patterns of plasticity across insect clades, but they are poorly understood within field contexts. Plastic responses and their evolution should be considered when predicting vulnerability to climate change-but meaningful empirical data lag behind theory.

How do phenology, plasticity, and evolution determine the fitness consequences of climate change for montane butterflies?

“…Conversely, constant wing melanin strongly reduces mean population fitness; and the evolution of wing melanin (without plasticity) causes only modest improvements in mean fitness. These results suggest that plasticity rather than evolution alone can make greater contributions to adaptive responses to climate change in this system (Charmantier et al., 2008; Sgro et al., 2016; Vedder et al., 2013). …”

“…However, the extent to which developmental plasticity and evolution are adaptive and influence fitness in variable, seasonal environments is poorly understood. Will their fitness consequences be sufficient to enable populations to track sustained climate changes in the coming decades (Sgro et al., 2016)?…”

Transgenerational seasonal timer for suppression of sexual morph production in the pea aphid, Acyrthosiphon pisum

“…Lees (1960) suggested that the seasonal timer would not result from a cytoplasmic substance which is diluted by cell division until it falls below a critical threshold, because the mechanism of the seasonal timer should resist many dilutions through several generations. Epigenetic mechanisms that alter the expression of DNA, however, can be passed on to one or more successive generations (Ho and Burggren, 2010;Sgrò et al, 2016). Although the role of epigenetic modification in reproductive polyphenism has not been studied, methylation levels in juvenile hormone associated genes are higher in winged asexual females than wingless asexual females in A. pisum (Walsh et al, 2010).…”

Parental thermal environment alters offspring sex ratio and fitness in an oviparous lizard

“…thermal parental effects), and may be equally important as thermal adaptation and acclimation (Angilletta, 2009;Sgro et al, 2016). For example, the timing and location of oviposition in egg-laying animals often responds to variation in temperature, and strongly influences developmental conditions (oviposition effects; Parmesan and Yohe, 2003;Doody et al, 2006;Schwanz and Janzen, 2008;Refsnider and Janzen, 2010;Schwanz et al, 2010a).…”

“…Surprisingly, there is a relative dearth of research on preoviposition parental effects due to temperature (Sgro et al, 2016). Yet, these effects are likely to be common given the demonstrated importance of other pre-oviposition factors such as maternal diet, maternal age and clutch order on offspring size, sex and behaviour (Mousseau and Dingle, 1991;Fox et al, 2003;Warner et al, 2008;Radder et al, 2009, Paranjpe et al, 2013.…”