Contrasting effects of acute heat shock on physiological and ecological performance of the fall armyworm

Abstract

Temperature is a critical factor that influences the behavior, physiology, and development of ectothermic organisms. This has become even more important as acute temperature stress associated with global climate change becomes the new norm. Using the invasive fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), we assessed its physiological and ecological responses following acute heat stress, synonymous to heat waves associated with recent climate change. Specifically, we measured the effects of short‐term exposure (for 2 h) to heat shock (at 32, 35, and 38 °C) on physiological responses, such as critical thermal minima (CTmin) and maxima (CTmax), and life‐history traits, such as reproductive success (fecundity and hatching success) and longevity, using virgin adults. Our results showed that prior acute heat shock compromised cold tolerance (CTmin) while enhancing heat tolerance (CTmax). In addition, heat shock reduced fecundity and hatching success and had dramatic effects on adult longevity. We conclude that acute heat stress associated with shifting environmental conditions may generally offset key physiological traits, affect reproduction and thus population persistence, and simultaneously have complex effects on adult lifespan.

Biology and management of fall army worm, Spodoptera frugiperda in maize crop at Karbi Anglong district of Assam

“…Lu et al (2023) [8] reported that the insect preferred maize and sorghum over the other plants, and performance was overall best on maize, but the insect was also able to complete its life cycle on the other plants. Mbande et al (2023) [9] studied the effects of simulated extreme weather conditions on low and high temperature tolerance and reproduction of fall army-worm adults, and reported that heat shock increased heat tolerance and decreased fecundity and egg hatching success. These results show that climate change may have unexpected effects on the spread of fall armyworm and its status as a pest.…”

Biology of fall armyworm – an introduction

“…Climate change may increase the number, as well as the severity of heat waves. Mbande et al (2023) studied the effects of simulated extreme weather conditions on low and high temperature tolerance and reproduction of fall armyworm adults, and found that heat shock increased heat tolerance, but decreased cold tolerance. Also, heat shock decreased fecundity and egg hatching success.…”