Short-Term Cold Stress Affects Parasitism on the Asian Chestnut Gall Wasp Dryocosmus kuriphilus

Abstract

Temperature variation affects interactions involving plants, herbivores, and parasitoids, causing a mismatch between their phenological cycles. In the context of climate change, climatic factors can undergo profound and sudden changes, such as sudden hot or cold snaps. Herein, we show that the number of episodes of short but sustained low temperatures has increased, mainly during May, over the last two decades. We subjected galls induced by the Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus to cold stress to assess whether and, if so, how it affected the pest and its parasitoids. Over the course of two years, we measured seasonal parasitism, parasitism rates, the relative abundance of each parasitoid species, and ACGW mortality. We found that the cold treatment affected both the pest and the parasitoids, resulting in a reduction in the emergence of ACGWs and differing ratios of species within the parasitoid community. The most striking example was the change in the relative frequency of three species of Eupelmus spp. and Mesopolobus tibialis, which doubled in cold-stressed galls in all chestnut fields. The effects of temperature on the development of the host and the direct effects of cold temperatures on the surface of galls (in terms of the humidity or hardness of the galls) warrant further research in this direction.

Influence of Climate Change on Chestnut Trees: A Review

“…Air temperature, air humidity, elevation, and soil can be counted as determining factors for the spread of diseases and pests in the chestnut tree. The temperature variation can act on different biological and evolutionary aspects, in the hosts and parasitoids, can reveal effects on the development and death of pathogenic individuals or reduced productivity [ 31 , 48 , 49 ]. Very wet springs can be detrimental, promoting the development of ink disease ( P. cinnamomi ) and white root rot disease ( Armillaria mellea ) [ 44 ].…”

“…Water and heat stress lessen plant growth and less vigor, also increasing susceptibility to biotic factors such as ink and blight diseases [ 29 ]. For some insect species, such as Mesopolobus tibialis , the population doubled when exposed to simulations of sudden stress events due to the cold temperatures (adaptive capacity) [ 49 ]. A variation in parasitism rates can be an immediate response to intraseasonal temperature variations, climate change, and variations in habitat.…”

Phototoxicity of Ultraviolet‐A against the Whitefly Bemisia tabaci and Its Compatibility with an Entomopathogenic Fungus and Whitefly Parasitoid

“…As a result, a change in parasitism rate could be described as an instant stress response [72][73][74]. The factors that influence parasitoid species composition are difficult to identify, and the reasons why some species react to stress more effectively than others have remained unclear [75].…”

Olive Production Threatened by a Resurgent Pest Liothrips oleae (Costa, 1857) (Thysanoptera: Phlaeothripidae) in Southern Italy

“…Ouyang et al [ 39 ] suggested that climate change and agricultural intensification of the Anthropocene could potentially induce outbreaks of many pest insects by weakening the density-dependent population regulation. Other factors are to be considered, such as those related to particular microclimatic variations or sudden hot or cold snaps [ 40 ] that have probably affected the area and that is being analyzed with new research.…”