The Ecology of Insect Overwintering

Abstract

Insect overwintering is a fascinating process involving many physiological, epidemiological, biochemical and behavioural changes. The study of the overwintering process can offer an insight into the development of insects, as well as help us to predict the patterns of crop damage and insect-borne disease caused by some insect species. This book provides a comprehensive account of the various forms of insect overwintering and highlights important areas of economic interest. It will be essential reading for advanced students and researchers in the fields of zoology, agriculture, forestry and ecology.

Population dependent effects of photoperiod on diapause related physiological traits in an invasive beetle (Leptinotarsa decemlineata)

“…The main reason is probably that migration, at the scale required for avoidance of adverse winter conditions, is energetically unfeasible for small ectotherms. However, also ectotherms overwintering in resting stages very often show spatial avoidance on a small scale, and overwinter in sheltered microclimates (Leather et al 1993).…”

“…Unlike more shallow dormancies, usually collectively called quiescence, which are direct results of non-cyclic deviations from normal weather conditions, and often are directly reversible upon the resumption of benign conditions, diapause is seen as the most elaborate, complex and highly evolved overwintering state (reviewed in e.g. Tauber et al 1986, Danks 1987, Leather et al 1993, Kostal 2006. Diapause is a neurohormonally mediated, genetically determined set of physiological events that occurs during a species specific stage of the life cycle, and can be either obligatory or facultative (Tauber et al 1986).…”

“…Variation in the intensity and mode of diapause is very large (Tauber et al 1986, Saunders 2002, Hahn & Denlinger 2007. For instance, while some insects do not eat and remain completely immobile during diapause, others can forage and move about, although often at a strongly reduced rate, when compared to non-diapausing counterparts (Leather et al 1993, Hahn & Denlinger 2007. Indeed, the notion of diapause as a complete temporal removal of the organism for a period of time is no longer appreciated; instead diapause is seen as a dynamic period of stress-related survival, managing of resources and sometimes even somatic development (Kostal 2006, Hahn & Denlinger 2007.…”

“…Representing the straightforward side, many temperate Lepidoptera overwinter as pupae, and thus overwinter where the larvae chose to form the pupae, locations which often are very exposed (such as a tree trunk) (Leather et al 1993, Willmer et al 2000. However, within taxon variation is large and another butterfly, the Monarch butterfly, Danaus plexippus, represents a complex strategy (Brower et al 1977).…”

“…Interestingly, where the travel south is completed in a single generation, the migration northwards is an annual expansion which encompasses up to four generations (Brower et al 1977). However, even though migration is common in temperate overwintering ectotherms, it is usually on a much smaller spatial scale, where animals seek out suitable microhabitats for overwintering (Leather et al 1993). Abiotic conditions can change dramatically depending on microhabitat and therefore many arthropods seek sheltered refugia where they overwinter, such as under snow, bark or burrowed into the soil.…”