Host behavioral manipulation

Parasites and the Behavior of Animals (Oxford Series in Ecology and Evolution)by Janice Moore, Oxford University Press, 2002. US$45.00 (315 pages) ISBN 019 508441 1Parasites and the Behavior of Animals has something for everyone, including ethologists, evolutionary ecologists, parasitologists, and physiologists like myself who would like to know more about how parasites influence host behavior. Janice Moore has an energetic and engaging style with which she describes the plethora of behavioral changes seen in parasitized animals and sets them in the proper ecological perspective. As she notes in the introduction, host behavior can influence both parasite-transmission rates and parasite–host survival. This fact sets the backdrop for the following survey. Throughout the animal kingdom, Moore finds fascinating examples of how the evolutionary trade offs of parasite versus host survival are carefully balanced, in most instances, in favor of the parasite involved. The physiological mechanisms responsible for the induction of these changes continue to remain speculative in most cases, but Moore does address the mechanistic processes involved in eliciting these changes in several instances.The central theme of the book is the Anderson and May model focusing on R0 or the reproductive rate as a measure of parasite fitness, which is the number of reproductive offspring that a parasite can produce. Those authors distinguished between the strategies of microparasites (e.g. bacteria and viruses) which are small and have a short life span, and which reproduce directly within the host, versus macroparasites (e.g. helminths, arthropods) which have larger bodies and longer life spans, and which disperse offspring from the host. What follows this introduction are chapters on behavioral alterations and parasite transmission, behavioral alterations and avoiding parasites, and the fitness and longevity of infected hosts, which altogether constitute a comprehensive review of the subject, so Moore is to be commended for her thoroughness. Topics such as behavioral fever and parasitic castration are dealt with in detail, and the evolutionary impact of these phenomena on parasite fitness (as well as host longevity and survival) is emphasized. The interplay between parasite offense and host defense is dissected at the finest level. Much less is known about the mechanisms responsible for the induction of host behavioral changes, but this is sure to change in the next decade.The tour de force of the book is the appendix, which comprises several tables citing literature for hundreds of host–parasite combinations in which host behavioral anomalies are found. References dealing with effects on host-feeding behavior, tropisms, activity levels, substrate preferences, social interactions and a myriad of other behaviors are included in the extensive bibliography. The classical literature, as well as up-to-date references, is included in the tables, rendering the appendix a valuable reference work, in itself justifying a purchase of the book.I wish the publisher had spent more on artwork and illustrative color photos, but the figures that are included complement the text nicely. The book is suitable to be used as a textbook for classes in behavior, evolution and host–parasite relationships, providing the right combination of overview and detail necessary in a text. This book has a minimum amount of jargon, and is thus appropriate for upper division undergraduates and graduates; its modest price is another plus for classroom use. Moore notes in the preface: ‘And I hope you have a good time reading this book’ – I truly did, and learned much by the experience.