Heartworm disease is probably the most well-known disease of dogs, and its epidemiology is being recorded in those countries in which the disease is routinely treated in the domestic dog. It is hoped that this text will be of benefit to us all and that our understanding of this disease will continue to grow and so enable us to resolve some of the exsiting problems associated with the treatment of this disease. To this end, the book aims to project some hypotheses in different areas that, while unproven, seem to be the most probable, based on our current knowledge.

Volume 9 in this series consists of four chapters on vectors that affect human or animal health and six chapters on plant pathogens and their vectors. In Chapter 1, Alex S. Raikhel discusses vitellogenesis in mosquitoes: the cornerstone of the reproductive cycle involving massive production of yolk precursors by the fat body and their accumulation in developing oocytes. In anautogeneous mosquitoes, vitellogenesis is dependent on the availability of a blood meal and, as a consequence, is linked to transmission of pathogens. Therefore, elucidation of mechanisms governing the mosquito vitellogenesis is critical for the successful development of novel strategies in vector and disease management. Previous reviews on mosquito vitellogenesis have dealt predominantly with hormonal control. The goal of this review, however, is to summarize significant progress which has been achieved in understanding mosquito vitellogenesis at the cellular, biochemical and molecular levels. It is with these disciplines that we expect to fully understand the mechanisms governing this key process in mosquito reproduction.

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.