Complex Life Cycles and the Responses of Insects to Climate Change

Abstract

Many organisms have complex life cycles with distinct life stages that experience different environmental conditions. How does the complexity of life cycles affect the ecological and evolutionary responses of organisms to climate change? We address this question by exploring several recent case studies and synthetic analyses of insects. First, different life stages may inhabit different microhabitats, and may differ in their thermal sensitivities and other traits that are important for responses to climate. For example, the life stages of Manduca experience different patterns of thermal and hydric variability, and differ in tolerance to high temperatures. Second, life stages may differ in their mechanisms for adaptation to local climatic conditions. For example, in Colias, larvae in different geographic populations and species adapt to local climate via differences in optimal and maximal temperatures for feeding and growth, whereas adults adapt via differences in melanin of the wings and in other morphological traits. Third, we extend a recent analysis of the temperature-dependence of insect population growth to demonstrate how changes in temperature can differently impact juvenile survival and adult reproduction. In both temperate and tropical regions, high rates of adult reproduction in a given environment may not be realized if occasional, high temperatures prevent survival to maturity. This suggests that considering the differing responses of multiple life stages is essential to understand the ecological and evolutionary consequences of climate change.

Thermal variation, thermal extremes and the physiological performance of individuals

“…It is also likely that the shape of thermal performance functions varies for the same organism at different levels of organization [e.g. mitochondria versus whole organism (Schulte et al, 2011)], for different performance traits (Huey, 1982) and for different ontogenetic stages (Kingsolver et al, 2011).…”

Changing Climate and Outbreaks of Forest Pest Insects in a Cold Northern Country, Finland

“…They live in a variety of microhabitats that experiencing very different climatic conditions. Consequently, considering the variable responses of different life stages to changing climate is essential to understand the impacts of climate change on pests (Kingsolver et al 2011). Many of the forest defoliators in the Boreal zone overwinter in the egg stage and feed on early season foliage (Hunter 1991).…”

Hotter nests produce hatchling lizards with lower thermal tolerance

“…Reptiles are particularly vulnerable to climate warming because environmental temperatures directly affect their physiology and behaviour (Araújo et al, 2006;Huey et al, 2012;Sinervo et al, 2010;Tewksbury et al, 2008). Predicting the vulnerability of ectotherms to climate warming requires knowledge of how increases in temperature will affect subsequent life-history stages (Kingsolver et al, 2011;Levy et al, 2015;Radchuk et al, 2013). Unlike adult lizards, developing lizard embryos cannot thermoregulate (Telemeco et al, 2016b) and, consequently, they may experience thermally stressful temperatures in natural nests during summer (Shine and Elphick, 2001).…”