Forest entomology in east africa h schabel (springer, 2006)

FOREST ENTOMOLOGY IN EAST AFRICA: FOREST INSECTS OF TANZANIA Forest Entomology in East Africa Forest Insects of Tanzania Hans G Schabel University of Wisconsin Wisconsin, U S A A C.I.P Catalogue record for this book is available from the Library of Congress ISBN-10 ISBN-13 ISBN-10 ISBN-13 1-4020-4654-5 (HB) 978-1-4020-4654-5 (HB) 1-4020-4655-3 (e-book) 978-1-4020-4655-3 (e-book) Published by Springer, P.O Box 17, 3300 AA Dordrecht, The Netherlands www.springer.com Printed on acid-free paper All Rights Reserved © 2006 Springer No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work Printed in the Netherlands DEDICATION To the people of Tanzania, whose kindness and cultural diversity are only matched by the natural wonders of their beautiful country Safari njema! TABLE OF CONTENTS Dedication v Preface ix Acknowledgments xiii Foreword xv Color Section xvii Introduction to Tanzania 1 General Physiography and soils Climate Natural forests Man-made forests 10 Protected forests 16 Endemism 18 History of Forest Entomology in Tanzania 23 Pre-colonial period (before 1891) 23 German colonial period (1891-1919) 24 British colonial period (1919-1961) 30 Post-independence (1961-1992) 32 Post-Rio (after 1992) 34 Defoliating Insects 37 Introduction 37 Defoliating Beetles (Coleoptera) 39 Defoliating caterpillars (Lepidoptera) 45 Defoliating grasshoppers (Saltatoria) 66 Sap-Feeding Insects 79 Introduction 79 Thrips (Thysanoptera) 79 Bugs (Hemiptera) 80 Shoot, Bark and Wood Borers 119 Introduction 119 Coleopterous borers 123 Hymenopterous borers 169 Lepidopterous borers 173 viii Table of CONTENTS Ants and Termites 179 Introduction 179 Ants (Formicidae) 180 Termites (Isoptera) 192 Flower, Fruit and Seed Feeders 217 Introduction 217 Flower-, fruit- and seed-feeding beetles 219 Fruit- and seed-feeding Hemiptera 230 Fruit- and seed-feeding Lepidoptera 233 Root and Root Collar Feeders 35 Introduction 235 Root-feeding Coleoptera 236 Root-feeding Hemiptera 239 Root collar-feeding Lepidoptera 241 Root-feeding Orthoptera 243 Forest-Based Insect Industries 247 Introduction 247 Edible insects (entomophagy) 250 Bees and beekeeping (apiculture) 258 Wild silk moths (sericulture) 270 Collectibles 277 References 295 Index 317 PREFACE In January 1983, while under contract with the Norwegian International Development Agency (NORAD), I started teaching Forest Entomology among other subject areas at Sokoine University of Agriculture (at that time still a branch of the University of Dar es Salaam) in Morogoro, Tanzania The task of delving into the tropical dimensions of forest biology and life in a different culture proved both challenging and exhilarating The wealth of insects was amazing, yet despite access to the University’s general library and a small collection of more specialized literature available at the Faculty of Forestry, no reference collection of insect specimens, no backup from other forest entomologists, no internet, and, importantly, not a single book dealing with the forest insects of Tanzania (or any part of Africa, for that matter) existed The East African Agricultural and Forestry Journal and a very basic field handbook of Malawi forest insects by Esbjerg (1976) provided the only relief in my efforts to acquaint myself with the most important pest insects of this ecologically diverse region Even today, in the wake of the rapidly expanding Information Age, an “enormous body of information is theoretically available, but it is highly dispersed, extraordinarily varied in form, uncoordinated, and largely unavailable in most of Africa” (Miller et al 2000) In the 1980s, without the benefit of the internet for rapid dissemination of information, conditions for research entomologists at African universities were even significantly more trying (Kumar 1987; Klopper et al 2002) Spurred on by these challenges, I embarked on a three-year personal mission to collect and assimilate as much information as possible through firsthand observation and field research, photographic documentation while on safari, interviews with oldtimers, extensive searches of the German colonial era records at the National Archives in Dar es Salaam and persistent probing for written records in obscure journals, proceedings and dusty government offices, that ultimately resulted in a growing stock of documents and knowledge I have returned to Tanzania six times in the intervening years, assembling in the process a comprehensive collection of German and English literature relevant to forest entomology in Tanzania, complemented by some French works on African entomology As reflected in this book’s extensive bibliography, Moffett’s 1958 claim that “literature on insects of Tanganyika is sparse” was a serious understatement This book is the culmination of more than 20 years of on-and-off research into the history of forest insects in Tanzania, in the process becoming my personal Kilimanjaro In both the German and x P REFACE British colonial periods there had been plans to write such a book, but unstable times and lack of a budget, respectively, had apparently not allowed this to happen For the purposes of this book, the term “East Africa” encompasses Uganda, Kenya, as well as Tanzania While the principal focus is on the forest insects of Tanzania, its two neighbors to the North are strongly linked to Tanzania historically, culturally and ecologically and thus should also benefit from access to this book Furthermore, since other countries in eastern, southern and central Africa share many species of insects with East Africa and provided relevant literature, this book should also be of use there The term “forest insects” as used in this book primarily refers to tree pest species affecting natural forests and woodlands, indigenous and exotic tree plantations, as well as tree nurseries Insects attacking wood at any stage, i.e., standing (living and dead), down (recently felled or dead logs), in storage or in use, have also traditionally been considered forest insects and thus are covered to at least some degree The most important predaceous and parasitic arthropods, which play important roles in the natural or biological control of forest pests, are also included In recognition of the increasing importance of trees in social and environmental contexts, insects associated with ornamental trees and rural development forests as pests, pest antagonists, or useful insects with the potential for income, have also been considered It is increasingly difficult to determine where tropical agriculture stops and forestry begins, but agroforestry clearly provides a hybrid model This land use practice emphasizes multipurpose trees that provide timber and non-timber products, while simultaneously serving for soil conservation, fertilization, fencing, shade and beauty While many woody legumes in particular meet multiple expectations, they can at the same time be magnets for a plethora of pests Also, as natural forests become depleted, tree crops that traditionally have been grown for fruit or specialty products are increasingly looked at as substitutes for timber trees in different parts of the tropics For instance, in Asia furniture is often built with wood from rubber trees, or trees such as mango, tamarind and jackfruit One eighth of timber in the Philippines already derives from coconut, and a significant share of Asia’s particleboard and fiberboard comes from tree crops, bamboo and agricultural fibers As a result of these trends, as well as for historic reasons, insects such as coconut rhinoceros beetles (Oryctes spp.) are included among the forest pests This book consists of three main parts: (1) two introductory chapters describing the natural history of Tanzania (2) six chapters detailing specific pest insects and their antagonists, and (3) one chapter focusing on forest insect industries Chapters and provide background on Tanzania’s physical environment, as well as its flora and forests Chapters 3-8 are arranged by feeding guilds, i.e., defoliators; sap feeders; bark, shoot and wood borers; termites and ants; flower, fruit and seed feeders; and finally root and root collar feeders As the important gall insects in Tanzania are mostly Hemiptera, they were placed into the chapter on sap feeders To pool ants and P REFACE xi termites in one chapter may be a somewhat unconventional arrangement, but these two unrelated groups share numerous similarities and interact in multiple ways, as explained in the introduction to that chapter The species profiles reflect those insects that have either caused the biggest and/or most persistent problems in tree culture in Tanzania, are the best known based on research in this country or elsewhere, are common, conspicuous, charismatic, unique, rare or of historic interest Their selection was frequently based on subjective judgments Some potentially troublesome invaders, such as the eucalyptus borers (Phoracantha spp.) and the newly described blue gum chalcid (Leptocybe invasa Fish & LaS.), insects that are already entrenched in other parts of Africa and have been approaching Tanzania, are briefly introduced In the case of insects that occur in Tanzania, but for which local data on bionomics may be scant or not exist, literature from as far as South and West Africa, Asia, the Pacific and even the Americas was exploited, despite the potential for significant regional differences in bionomics Common insect names listed are mostly based on Crowe (1967) A broad, general overview of each family or order precedes most categories of insects Individual generic or species profiles typically provide details on occurrence and damage, describe different developmental stages, outline life history and synopsize historically important or contemporary management practices Material presented for each insect species or genus reflects the extent of existing knowledge and level of interest For insects of more marginal interest, only the bare essentials are covered Many forest insects, for which only host records are available, have been ignored Coverage of groups of insects or hosts is presented alphabetically Chapter considers forest-based insects that have income potential for local people and thus may provide incentives for the retention or restoration of functional forests This includes segments on edible insects, bee products, wild silk and collectibles Reference to certain insects in multiple chapters was inevitable For instance, the emperor moths (Saturniidae) are folivore tree pests and thus are first covered among defoliators At the same time they are edible, some are silk producers and most are collectibles, for which reason relevant aspects were also dealt with in other appropriate contexts In recent years the taxonomy of arthropods has been debated intensely with little apparent resolution among the experts As a result, this book largely follows the traditional classificational system, incorporating some of the more recent revisions The presence of numerous synonyms for certain species and other taxonomic levels posed a recurrent challenge during the preparation of this book Every effort was made to meet current entomological standards Nevertheless, persistent disagreement on terminology even among specialists guarantees that segments of this book will fall afoul of bewildering taxonomic complexities and inconsistencies Authority citations for species names are provided where available, but are missing for others for lack of definitive references .. .FOREST ENTOMOLOGY IN EAST AFRICA: FOREST INSECTS OF TANZANIA Forest Entomology in East Africa Forest Insects of Tanzania Hans G Schabel University of Wisconsin Wisconsin, U S A A... and thus shares in their glory Unless indicated otherwise, the photos are the author’s I also owe gratitude to Christine Neidlein and Bob Shaw, both librarians for the University of Wisconsin,... Agriculture in Morogoro, Tanzania At the time he faced having to teach forest entomology without the benefit of a readily available and comprehensive resource During the intervening years he has been