Insects and low temperatures: from
theory to applications
University of Birmingham, UK
Insects are highly successful animals, inhabiting marine, freshwater and terrestrial environments from the equator to the poles. As a group, insects have limited ability to regulate their body temperature and so have required a range of strategies to support life in stressful environments, including behavioural avoidance through migration, and physiological adaptations such as diapause and changes in thermal tolerance. With respect to low temperature survival, insects are broadly divided into two main groups: freeze tolerant and freeze avoiding. However, this simple classification belies a diversity of responses, including synthesis of cold-protective metabolites (cryoprotectants), antifreeze proteins, ice-nucleating agents, molecular chaperones and changes in lipid composition to facilitate membrane adaptation. Advances in technology, particularly the emergence of genomics, metabolomics and lipidomics, have significantly increased our understanding of the mechanisms underpinning cold adaptation, and it will play an important role in future research.
The implications of climate change
for insects are likely to be variable, with the rate of change determining the
capacity of species to adapt. Possible benefits include faster development and
reproduction, increases in voltinism, and range expansion. Negative effects
include decoupling of the seasonal cues programming diapause, habitat loss at
low latitude range boundaries, and thermal niche constriction in mountainous
regions. Increasing our knowledge of insect thermal biology under current
regimes is essential for predicting the impacts of a changing climate on future
patterns of distribution and abundance. This information has direct
applications in areas such as the prediction of pest outbreaks and
establishment potential of invasive species.