Increases in both temperature means and extremes likely facilitate invasive herbivore outbreaks

Abstract

Although increases in mean temperature (MT) and extreme high temperature (EHT) can greatly affect population dynamics of insects under global warming, how concurrent changes in both MT and EHT affect invasive species is largely unknown. We used four thermal regimes to simulate the increases in summer temperature and compared their effects on the life-history traits of three geographical populations (Chongqing, Wuhan and Shanghai) of an invasive insect, Corythucha ciliata, in China. The four thermal regimes were control (i.e., natural or ambient), an increase in MT (IMT), an increase in EHT, and a combination of IMT + EHT. We found that the three warming regimes significantly increased the developmental rate but did not affect the survival, sex ratio, longevity, or fecundity of C. ciliata. Consequently, the intrinsic rate of natural increase (rm) was enhanced and the number of days required for population doubling (t) was reduced by the warming regimes. The demographic parameters did not significantly differ among the three populations. These results indicate that population size of C. ciliata may be enhanced by increases in both temperature means and extremes. The increases in summer temperature associated with climate change, therefore, would likely facilitate population outbreaks of some thermophilic invasive insects.

Multi‐scale responses to warming in an experimental insect metacommunity

“…While the insectinduced plant mortality we observed is indicative of some degree of resource limitation in this system, the patterns of insect co-occurrence and correlated abundances suggest that here, competition for resources was not a major driver of insect behavior or population growth ( Figure 2). When resource limitation or temperature stress do not limit population growth, warming can accelerate reproductive rates and induce larger populations of species with rapid reproduction and overlapping generations such as aphids (Barton & Ives, 2014;Ju, Zhu, Gao, Zhou, & Li, 2015). When resource limitation or temperature stress do not limit population growth, warming can accelerate reproductive rates and induce larger populations of species with rapid reproduction and overlapping generations such as aphids (Barton & Ives, 2014;Ju, Zhu, Gao, Zhou, & Li, 2015).…”

“…Warming experiments have reported both positive and negative effects of warming on species performance, with the direction of these effects depending on species identity, the ranges of temperatures used, the individual or population response of interest, and the nature and strength of species interactions (Bale et al, 2002;Barton & Schmitz, 2009;Gruner et al, 2017;Jiang & Morin, 2004;O'Connor, 2009;Walker et al, 2006). When resource limitation or temperature stress do not limit population growth, warming can accelerate reproductive rates and induce larger populations of species with rapid reproduction and overlapping generations such as aphids (Barton & Ives, 2014;Ju, Zhu, Gao, Zhou, & Li, 2015). Indeed, we saw a positive effect of warming on aphid abundances (Figure 3).…”

Resolving biological impacts of multiple heat waves: interaction of hot and recovery days

“…Previous studies indicate that the intensity of heat waves can have important consequences. For instance, maximum day temperature of heat waves can alter demographic rates, fitness, and phenology of individuals, population dynamics (Ju et al 2015, Ma et al 2015a, and community structure (Gillespie et al 2012, Sentis et al 2013, Ma et al 2015b, even when mean temperatures were below the critical maximum. Similarly, high nighttime temperature exacerbates the detrimental effects of hot days on the demographics and fitness and subsequently decreases risk for pest outbreaks (Zhao et al 2014).…”

Temperature Thresholds and Thermal Requirements for Development and Survival of Dysmicoccus brevipes (Hemiptera: Pseudococcidae) on Table Grapes

“…Knowledge of the thermal requirements for D. brevipes development is essential to estimate the seasonal occurrence of the pest in vineyards, its potential growth in different producing regions, and population outbreaks. This is even more important in view of the expansion of grapevine cultivation to different regions of Brazil, especially those in a tropical region (Protas 2016), and the impact of climatic changes on insect populations (Robinet & Roques 2010, Ju et al 2015.…”