Heteroptera of Economic Importance PDF

Preface

This book began as an all-morning conversation between its two editors, during the International Congress of Entomology, in Beijing, China, in 1992. The great importance of heteropterans as pests of crops, as vectors of a major disease (Chagas' disease), and as biological control agents of great but often untested importance persuaded us that a book on the subject was needed. Such a book, detailed and thorough, would help agriculturists in all parts of the world, and would we hoped lead to further work on the agricultural biologies and ecologies of these insects. By bringing this information together, the current and past status of pest species, or their current and past value as biological control agents, could be assessed. By so doing, we believe, it may even be possible to predict where and by what species other pests may emerge (for example, African relatives of a lace bug pest on crop X in Asia may one day become pests on crop X in Africa; see Schaefer 1998).

We thought first to put together a symposium for the next Congress. But the organizers turned down our proposal ("too narrow"), which solved a problem for us: there were too many groups to be covered in one symposium, and we were at a loss to decide who should be invited for the book, but not for the symposium. In any event, the book emerges un-Congressionally heralded. We do not feel it is the less for that.

Each chapter is written by one or a few authorities on a taxonomic group of heteropterans. We felt that such authorities would have the best knowledge of the general literature, and therefore the quickest access to the economic literature on their groups. One result of this reliance on the groups' authorities has been a remarkable completeness in the coverage of the literature — there are some 4500 references cited in this book.

Indeed, our most important instruction to each author was to be complete, to cover the relevant literature as completely as possible, and to interpret "relevant" as broadly as possible. Our aim has been to provide the reader with a starting point, a point d'appui from which to launch further studies on heteropterans of economic importance. We are quite and regretfully aware that completeness is impossible, that past literature (some of it important) has been overlooked, and that more important literature has appeared while this book has been in press. Each of the editors has added material to the chapters of others (and to our own), as we have come upon it.

The authors agreed with our desire for completeness. As a result, these chapters contain thorough and detailed accounts of the biologies of the economically important heteropterans, accounts often more detailed than occur elsewhere. We believe, therefore, that the book sets forth as complete a series of heteropteran biologies as can be found anywhere. Moreover, the bringing of this information together in one place makes possible for the first time various comparisons and analyses.

However, in many cases, life-history and biological data are scant. This reflects the state of the literature on these insects and not the authors' knowledge of that literature. It seems indeed remarkable that so little is known about so many pests. If control of these pests is ever to be permanently effected, their biologies must be studied; ignoring this simple truth will not allow one to avoid its consequences.

We note that some chapters are less detailed than others, although each certainly covers its subject thoroughly. Very recent books on Reduviidae and Miridae, by Ambrose (1999) and Wheeler (2001), respectively, and another, less recent one on Cimicidae (Usinger 1966), make detailed chapters on these families less necessary. Nevertheless, each chapter stands alone as a compendium of what is known of its group; each chapter will by itself bring readers up-to-date on its subject, and introduce them to the literature of that subject. That is the purpose of this book, and it is a purpose useful as much to students of heteropteran systematics, biology, and ecology, as it is to those more directly concerned with the economic significance of heteropterans.

The organization of each chapter is straightforward and, for the most part, uniform. However, we have not placed authors in organizational straitjackets, and we have allowed each some leeway. Each chapter is complete in itself, but the interested reader can move easily from one to another, confident that the format of each will be familiar. We have also tried to aid such movement by cross-referencing relevant chapters and sections.

The book itself has two divisions, each opening with a general chapter. The section on heteropterans as pests opens with a chapter on how these insects adversely affect plants, and the first chapter in the section on beneficial heteropterans considers how in fact predaceous heteropterans feed. However, we point out that not all the heteropterans in the first part of this book are harmful, nor are all of those in the second part useful. Some actual or potential biological control agents occur within families most of whose members harm plants, and a few predaceous groups contain members that pose a minor threat to fisheries. Like many of our friends, there is a little bit of bad in the best of them, and a little bit of good in the worst. This incomplete dichotomy is seen in the two Miridae chapters, where sometimes the same species is described as both harmful and useful; again, among the stilt bugs are some insects causing damage and others of some value in biological control.

The Tingidae exemplifies another problem we faced in this book — the decision whether a species is an "important species" or a "less important species" is often a subjective one. If a species does major damage only occasionally, is it important or less important? If a species does small damage often, is it important or less important? If a species does considerable damage in only one small part of the world, is it important or less important? When does "occasionally" merge into "often"? How small is "one small part of the world"? If a certain Indian farmer's brinjal crop is destroyed for several years running, the damage is certainly important to him and his family (see Chapter 4, Section 3.18 ). But if the brinjal lace bug is serious only in this farmer's state, do the editors of this book consider the bug an important pest? We editors can only state that we have tried in each case to follow the assessment of each chapter author(s), and in some cases to make our own best (if imperfect) judgment. Readers may disagree with these decisions, which, however, are less important than that all pests — major and minor — are (we believe) included.

Two final words of explanation. Readers should be aware that the names used herein are for the most part those of the authors reviewed. Yet applied entomologists, dealing as they are with immediate problems, may not take the time needed for accurate identification of their pests. As a result, pests may be misidentified in the literature, and these misidentifications perpetuated in the secondary literature (like this book). For example, the cotton stainers Dysdercus koenigii (F.) and D. cingulatus (F.) are distinct speces whose distributions overlap only narrowly, in northeastern India and Bangladesh (Freeman 1947, Kapur and Vazirani 1956). Yet in the considerable literature on these bugs, there appears to have been little if any attempt to distinguish between them. The two names are used almost indiscriminately, and not only by applied entomologists — but by physiologists, endocrinologists, and others for whom correct systematics is more a burden than a useful predictor.

Where possible, we have corrected scientific names and identifications. Nevertheless, errors perforce occur. We only plead that we have done our best and that we ourselves have introduced new errors very rarely.

We have tried to give the authors of all scientific names. We believe we have succeeded with heteropterans, but have been less successful with other arthropods, and least successful with plants. We have also tried to use accepted scientific names, with the same declining degrees of success. We apologize for any nomenclatorial errors, while acknowledging that some are inevitable. With respect to the authors of plant names, we point out that our bible (Howes 1974) eschews authors completely. Finally, we spell out all authors' names except Linnaeus (L.) and Fabricius (F. or Fabr.), and those names which, abbreviated in our sources, we did not recognize.