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.

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).

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.

Temperature is one facet in the mosaic of physical and biotic factors that describes the niche of an animal. Ofthe physical factors it is ecologically the most important. for it is a factor that is all-pervasive and one that. in most environments. lacks spatial or temporal constancy. Evolution has produced a wide variety of adaptive strategies and tactics to exploit or deal with this variable environmental factor. The ease with which temperature can be measured. and controlled experimentally. together with its widespread influence on the affairs of animals. has understandably led to a large. dispersed literature. In spite of this no recent book provides a comprehensive treatment of the biology of animals in relation to temperature. Our intention in writing this book was to fill that gap. We hope we have provided a modern statement with a critical synthesis of this diverse field. which will be suitable and stimulating for both advanced undergraduate and post graduate students of biology. This book is emphatically not intended as a monographical review. as thermal biology is such a diverse. developed discipline that it could not be encompassed within the confines of a book of this size.

The dipteran family Chironomidae is the most widely distributed and frequently the most abundant group of insects in freshwater, with rep resentatives in both terrestrial and marine environments. A very wide range of gradients of temperature, pH, oxygen concentration, salinity, current velocity, depth, productivity, altitude and latitude have been exploited, by at least some chironomid species, and in grossly polluted environments chironomids may be the only insects present. The ability to exist in such a wide range of conditions has been achieved largely by behavioural and physiological adaptations with relatively slight morphological changes. It has been estimated that the number of species world-wide may be as high as 15000. This high species diversity has been attributed to the antiquity of the family, relatively low vagility leading to isolation, and evolutionary plasticity. In many aquatic ecosystems the number of chironomid species present may account for at least 50% of the total macroinvertebrate species recorded. This species richness, wide distribution and tolerance to adverse conditions has meant that the group is frequently recorded in ecological studies but taxonomic difficulties have in the past prevented non-specialist identification beyond family or subfamily level. Recent works, including genetic studies, have meant that the family is receiving much more attention globally.

Insects, being poikilothermic, are among the organisms that are most likely to respond to changes in climate, particularly increased temperatures. Range expansions into new areas, further north and to higher elevations, are already well documented, as are physiological and phenological responses. It is anticipated that the damage by insects will increase as a consequence of climate change, i.e. increasing temperatures primarily. However, the evidence in support of this common “belief” is sparse. Climate Change and Insect Pests sums up present knowledge regarding both agricultural and forest insect pests and climate change in order to identify future research directions.

Comprehensive account of the various forms of insect overwintering, highlighting areas of economic interest.

Blood-sucking insects are the vectors of many of the most debilitating parasites of man and his domesticated animals. In addition they are of considerable direct cost to the agricultural industry through losses in milk and meat yields, and through damage to hides and wool, etc. So, not surprisingly, many books of medical and veterinary entomology have been written. Most of these texts are organized taxonomically giving the details of the life-cycles, bionomics, relationship to disease and economic importance of each of the insect groups in turn. I have taken a different approach. This book is topic led and aims to discuss the biological themes which are common in the lives of blood-sucking insects. To do this I have concentrated on those aspects of the biology of these fascinating insects which have been clearly modified in some way to suit the blood-sucking habit. For example, I have discussed feeding and digestion in some detail because feeding on blood presents insects with special problems, but I have not discussed respiration because it is not affected in any particular way by haematophagy. Naturally there is a subjective element in the choice of topics for discussion and the weight given to each. I hope that I have not let my enthusiasm for particular subjects get the better of me on too many occasions and that the subject material achieves an overall balance.