Cold and freezing injury in insects: An overview of molecular mechanisms

The present review discusses the molecular mechanisms of injury caused by low temperatures and/or freezing. The review is intended mainly for insect environmental physiologists who focus on the effects of low temperatures. The review successively discusses (1) the effects of low temperatures on the structure and function of macromolecules; (2) the effects of freezing on cells and macromolecules and (3) the mechanisms of damage during thawing and post-thaw. The review shows that injury primarily occurs at the molecular level in terms of damage to proteins, nucleic acids and biological membranes. The damage to macromolecular structures occurs as a result of the interaction between the effects of temperature, ice formation and resulting secondary effects such as osmotic stress, increased concentration of solutes, cellular freeze dehydration, disruption of ionic balance and oxidative stress. The present review attempts to identify gaps in our knowledge on the mechanisms of cold injury in organisms and proposes possible future directions that could contribute to fi lling the gaps. * This paper was contributed to a virtual special issue in memory of Ivo Hodek, a long-time editor of the European Journal of Entomology, who died on June 11, 2021, shortly after his ninetieth birthday.