A metabolomic analysis of the freeze tolerant midge, Belgica antarctica, revealed that freezing increased a number of different polyols in whole-body extracts, incuding glycerol, mannitol, and erythritol. Freezing also increased alanine, asparagine, and glycine. In addition, the frozen midge larvae accumulated Krebs cycle intermediates, indicating that aerobic respiration is considerably slowed. Membrane involvement in freezing was not conclusively supported, although there was a reduction in oleic acid levels. A comparison of the metabolic responses of this midge to heat, freezing and desiccation revealed that freezing and desiccation produced similar results, supporting the hypothesis that the cellular response to these two stressors is related.

Low temperature is a major environmental constraint impacting the geographic distribution and seasonal activity patterns of insects. Written for academic researchers in environmental physiology and entomology, this book explores the physiological and molecular mechanisms that enable insects to cope with a cold environment and places these findings into an evolutionary and ecological context. An introductory chapter provides a primer on insect cold tolerance and subsequent chapters in the first section discuss the organismal, cellular and molecular responses that allow insects to survive in the cold despite their, at best, limited ability to regulate their own body temperature. The second section, highlighting the evolutionary and macrophysiological responses to low temperature, is especially relevant for understanding the impact of global climate change on insect systems. A final section translates the knowledge gained from the rest of the book into practical applications including cryopreservation and the augmentation of pest management strategies.

Abstract: As ectotherms with high surface area to volume ratio, insects are particularly susceptible to desiccation and low temperature stress. In this dissertation, I examine the molecular underpinnings of two facets of these stresses: rapid cold hardening and cryoprotective dehydration.

The study of insects at low temperature is a comparatively new field. Only recently has insect cryobiology begun to mature, as research moves from a descriptive approach to a search for underlying mechanisms at diverse levels of organization ranging from the gene and cell to ecological and evolutionary relationships. Knowledge of insect responses to low temperature is crucial for understanding the biology of insects living in seasonally varying habitats as well as in polar regions. It is not possible to precisely define low temperature. In the tropics exposure to 10-15°C may induce chill coma or death, whereas some insects in temperate and polar regions remain active and indeed even able to fly at O°C or below. In contrast, for persons interested in cryopreservation, low temperature may mean storage in liquid nitrogen at - 196°C. In the last decade, interest in adaptations of invertebrates to low temperature has risen steadily. In part, this book had its origins in a symposium on this subject that was held at the annual meeting of the Entomological Society of America in Louisville, Kentucky, USA in December, 1988. However, the emergence and growth of this area has also been strongly influenced by an informal group of investigators who met in a series of symposia held in Oslo, Norway in 1982, in Victoria, British Columbia, Canada in 1985 and in Cambridge, England in 1988. Another is scheduled for Binghamton, New York, USA (1990).

The study of insects at low temperature is a comparatively new field. Only recently has insect cryobiology begun to mature, as research moves from a descriptive approach to a search for underlying mechanisms at diverse levels of organization ranging from the gene and cell to ecological and evolutionary relationships. Knowledge of insect responses to low temperature is crucial for understanding the biology of insects living in seasonally varying habitats as well as in polar regions. It is not possible to precisely define low temperature. In the tropics exposure to 10-15°C may induce chill coma or death, whereas some insects in temperate and polar regions remain active and indeed even able to fly at O°C or below. In contrast, for persons interested in cryopreservation, low temperature may mean storage in liquid nitrogen at - 196°C. In the last decade, interest in adaptations of invertebrates to low temperature has risen steadily. In part, this book had its origins in a symposium on this subject that was held at the annual meeting of the Entomological Society of America in Louisville, Kentucky, USA in December, 1988. However, the emergence and growth of this area has also been strongly influenced by an informal group of investigators who met in a series of symposia held in Oslo, Norway in 1982, in Victoria, British Columbia, Canada in 1985 and in Cambridge, England in 1988. Another is scheduled for Binghamton, New York, USA (1990).

Insect physiology is currently undergoing revolutionary changes with the increased application of molecular biological techniques to investigate the molecular mechanisms underlying the physiological responses to insect cells. Advances in Insect Physiology is committed to publishing high quality reviews on molecular biology and molecular genetics in areas where they provide an increased understanding of physiological processes in insects. Volume 27 of this classic series continues to provide up-to-date reviews on topical subjects of importance to all invertebrate physiologists and neurobiologists and contains increased coverage on the molecular biology of insect physiology.

Our highly seasonal world restricts insect activity to brief portions of the year. This feature necessitates a sophisticated interpretation of seasonal changes and enactment of mechanisms for bringing development to a halt and then reinitiating it when the inimical season is past. The dormant state of diapause serves to bridge the unfavourable seasons, and its timing provides a powerful mechanism for synchronizing insect development. This book explores how seasonal signals are monitored and used by insects to enact specific molecular pathways that generate the diapause phenotype. The broad perspective offered here scales from the ecological to the molecular and thus provides a comprehensive view of this exciting and vibrant research field, offering insights on topics ranging from pest management, evolution, speciation, climate change and disease transmission, to human health, as well as analogies with other forms of invertebrate dormancy and mammalian hibernation.

Now that many of the clock genes have been identified it is possible to track daily patterns of clock-related mRNAs and proteins to link the entraining light cycles with molecular oscillations within the cell. Insect experiments have led the way in demonstrating that the concept of a "master clock" can no longer be used to explain the temporal organization within an animal. Insects have a multitude of cellular clocks that can function independently and retain their function under organ culture conditions, and they thus offer a premier system for studying how the hierarchical organization of clocks results in the overall temporal organization of the animal. Photoperiodism, and its most obvious manifestation, diapause, does not yet have the molecular underpinning that has been established for circadian rhythms, but recent studies are beginning to identify genes that appear to be involved in the regulation of diapause.

Ecologists have always believed, at least to a certain extent, that physiological mechanisms serve to underpin ecological patterns. However, their importance has traditionally been at best underestimated and at worst ignored, with physiological variation being dismissed as either an irrelevance or as random noise/error. Spicer and Gaston make a convincing argument that the precise physiology does matter! In contrast to previous works which have attempted to integrate ecology and physiology, Physiological Diversity adopts a completely different and more controversial approach in tackling the physiology first before moving on to consider the implications for ecology. This is timely given the recent and considerable interest in the mechanisms underlying ecological patterns. Indeed, many of these mechanisms are physiological. This textbook provides a contemporary summary of physiological diversity as it occurs at different hierarchical levels (individual, population, species etc.), and the implications of such diversity for ecology and, by implication, evolution. It reviews what is known of physiological diversity and in doing so exposes the reader to all the key works in the field. It also portrays many of these studies in a completely new light, thereby serving as an agenda for, and impetus to, the future study of physiological variation. Physiological Diversity will be of relevance to senior undergraduates, postgraduates and professional researchers in the fields of ecology, ecological physiology, ecotoxicology, environmental biology and conservation. The book spans both terrestrial and marine systems.

The publication of the extensive seven-volume work Comprehensive Molecular Insect Science provided a complete reference encompassing important developments and achievements in modern insect science. One of the most swiftly moving areas in entomological and comparative research is molecular biology, and this volume, Insect Molecular Biology and Biochemistry, is designed for those who desire a comprehensive yet concise work on important aspects of this topic. This volume contains ten fully revised or rewritten chapters from the original series as well as five completely new chapters on topics such as insect immunology, insect genomics, RNAi, and molecular biology of circadian rhythms and circadian behavior. The topics included are key to an understanding of insect development, with emphasis on the cuticle, digestive properties, and the transport of lipids; extensive and integrated chapters on cytochrome P450s; and the role of transposable elements in the developmental processes as well as programmed cell death. This volume will be of great value to senior investigators, graduate students, post-doctoral fellows and advanced undergraduate research students. It can also be used as a reference for graduate courses and seminars on the topic. Chapters will also be valuable to the applied biologist or entomologist, providing the requisite understanding necessary for probing the more applied research areas related to insect control. - Topics specially selected by the editor-in-chief of the original major reference work - Fully revised and new contributions bring together the latest research in the rapidly moving fields of insect molecular biology and insect biochemistry, including coverage of development, physiology, immunity and proteomics - Full-color provides readers with clear, useful illustrations to highlight important research findings