Insects and low temperatures: from molecular biology to distributions and abundance

Abstract

Insects are the most diverse fauna on earth, with different species occupying a range of terrestrial and aquatic habitats from the tropics to the poles. Species inhabiting extreme low-temperature environments must either tolerate or avoid freezing to survive. While much is now known about the synthesis, biochemistry and function of the main groups of cryoprotectants involved in the seasonal processes of acclimatization and winter cold hardiness (ice-nucleating agents, polyols and antifreeze proteins), studies on the structural biology of these compounds have been more limited.The recent discovery of rapid cold-hardening, ice-interface desiccation and the daily resetting of critical thermal thresholds affecting mortality and mobility have emphasized the role of temperature as the most important abiotic factor, acting through physiological processes to determine ecological outcomes. These relationships are seen in key areas such as species responses to climate warming, forecasting systems for pest outbreaks and the establishment potential of alien species in new environments.

Cold hardening processes in the Antarctic springtail, Cryptopygus antarcticus: Clues from a microarray

“…For these organisms the SCP is equal to their lower lethal temperature. This is not the case for all arthropods as some have been shown to die before they freeze (chill susceptible) (Bale, 2002). Other factors such as the cooling rate can affect the measured SCP and the lower lethal temperature (Worland, 2005).…”

Role of membrane transport of water and glycerol in the freeze tolerance of the rice stem borer, Chilo suppressalis Walker (Lepidoptera: Pyralidae)

“…Insect cold tolerance has been divided for practical purposes into two main categories. Freeze-tolerant species survive ice formation in their bodies, and freeze-intolerant species die if frozen but survive by supercooling (reviews by Storey and Storey, 1992;Danks, 1996;Sømme, 1999;Duman, 2001;Bale, 2002).…”

Responses of invertebrates to temperature and water stress: A polar perspective

“…This risk is generally ameliorated by adoption one of two strategies -84 freeze-tolerance (= tolerance of internal ice formation) or freeze-avoidance (= avoidance of internal 85 ice formation) (Bale 2002; Cannon and Block 1988;Convey 1996; Storey and Storey 1988;86 Zachariassen 1985). 87…”

“…Key to this process is the 97 accumulation of ice nucleating agents (INAs), such as specialised proteins ), food 98 particles, crystalloid compounds and microorganisms (Klok and Chown 1997;99 Worland and Block 1999), which act as heterogeneous surfaces for the promotion of water molecule 100 aggregation (Bale 2002 Wharton 2003aWharton , 2003bWharton , 2011b. 112…”

“…Enhanced supercooling is principally 148 achieved via three processes, and thus involves fewer core stress response mechanisms than freeze 149 tolerance (Bale 2002 ceramboides, would vitrify. Upis ceramboides freezes at high sub-zero temperatures and is able to 242 survive in this frozen state to -60°C (Miller 1978).…”