590.5 FI V.47 Cop

LIBRARY OF THE UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN 590.5 FI V.47 cop. 3 NAIURALH I iJ=reRy SURVEY I/. 4-T The Systematics, Evolution and Zoogeography OF STAPHYLINID BEETLES Associated with Army Ants (COLEOPTERA, StAPHYLINIDAe) CHARLES H. SEEVERS ^UG 1 8 1965 UBRARY *^ ,,,.M^*^*' FIELDIANA: ZOOLOGY VOLUME 47, NUMBER 2 Published by CHICAGO NATURAL HISTORY MUSEUM MARCH 22, 1965 rHE SySTEMATICS, EVOLUTION AND ZOOGEOGRAPHY OF STAPHYLINID BEETLES Associated with Army Ants (COLEOPTERA, StAPHYLINIDAE) CHARLES H. SEEVERS Research Associate, Division of Insects Professor of Zoology, Roosevelt University FIELDIANA: ZOOLOGY VOLUME 47, NUMBER 2 Published by CHICAGO NATURAL HISTORY MUSEUM MARCH 22, 1965 Edited by Edward G. Nash Library of Congress Catalog Card Number: 65-18865 PRINTED IN THE UNITED STATES OF AMERICA BY CHICAGO NATURAL HISTORY MUSEUM PRESS CONTENTS PAGE Introduction 141 Acknowledgements 144 The Army Ants (Dorylinae) 147 Tribes Cheliomyrmicini, Ecitonini, Dorylini, and Aenictini 148 Behavior Cycles of Representative Dorylines 150 Evolutionary Considerations 155 Mechanisms of Social Integration 156 Morphological Specializations 157 Types of Abdominal Petioles 158 Limuloid Dorylophiles 159 Regressive Specializations 160 The Dorylophilous Tribe Dorylomimini (Aleocharinae) : Organization, Phylogeny, and Zoogeography 161 Introduction 161 Dorylomimini of the Ethiopian Region 165 Dorylomimini of the Oriental Region 166 Dorylomimini of the New World 167 The Tribe Myrmedoniini (Aleocharinae) : Convergent Evolution of Dorylophilous Groups 170 Tribal Composition 170 The Dorylophilous Components of the Tribe 171 The Old World Dorylophilous Tribe Pygostenini (Aleocharinae) .... 174 The Neotropical Ecitophilous Tribe Ecitogastrini (Aleocharinae) .... 175 The Neotropical Ecitophilous Tribe Ecitocharini (Aleocharinae) .... 175 The Ethiopian Tribe Deremini (Aleocharinae) 176 Ecitophilous Paederinae, Staphylinidae, and Tachyporinae 176 Systematic Section 181 Genera of Dorylophilous Staphylinidae 181 Subfamily Aleocharinae 186 Key to Old World Tribes with Dorylophilous Genera 186 Key to New World Tribes with Ecitophilous Genera 186 Tribe Dorylomimini 187 139 140 CONTENTS A Key to the New World Genera 207 Tribe Mjo-medoniini 232 A Key to the New World Genera 233 New World Ecitophilous Groups 236 Old World Dorylophilous Groups 274 Tribe Ecitocharini, new tribe 287 Tribe Deremini, new tribe 294 Tribe Ecitogastrini 300 Tribe Pygostenini 303 Tribe Phyllodinardini 309 Tribe Trilobitideini 312 Tribe Aleocharini 314 Subfamily Paederinae; Tribe Paederini 315 Subfamily Staphylininae 323 Tribe Staphylinini 328 Tribe Quediini 329 Subfamily Tachyporinae; Tribe Vatesini 332 Subfamily Oxytelinae 339 Position uncertain: Synaenictus Patrizi 341 Bibliography 343 140 INTRODUCTION As one of the dominant groups of insect predators the beetle family Staphylinidae has attained great success. Representatives of its more than 28,000 recorded species occur in almost every in- habitable terrestrial area of the world, and occupy important places in many types of ecological communities. Most staphylinids live in decaying organic materials where there is an abundance of larvae and other soft-bodied arthropods and where their predatory activ- ities are generalized in character. Some members of the family have achieved notable success in adapting to such specialized ecological systems as ant and termite societies. Successful adaptation to insect societies requires some measure of obligatory social integration, and inquilinous species in all likelihood must conform to species spe- cific physiological integrative mechanisms of a chemo-tactic nature. The success of the Staphylinidae in adjusting to life in insect social systems is indicated by the fact that the number of independently evolved groups of termitophilous and myrmecophilous species ex- ceeds that of any other family of organisms. This monograph attempts to explore certain aspects of the evolution of one category of myrmecophilous Staphylinidae—those associated with army ants (Dorylinae) of the world. The central theme is the evolution and zoogeography of interspecies systems composed of doryline ant societies and their staphylinid dorylophiles. As the basis for a synthesis it has been necessary for me to restudy the classification of more than one hundred dorylophile genera, and to reor- ganize the categories, usually tribes, to which they belong. The results of these systematic studies lead me to conclude that there are more than twenty independently evolved groups of dorylophilous Staphylinidae (Table 1). Ideally, each of the groups should be monophyletic and be based on the successful establishment of a single dorylophilous species at some remote geologic time. A majority of dorylophilous Staphylinidae belong to the subfamily Aleocharinae, an extremely large and complex taxon. Inas- much as the tribal classification of this subfamily has developed as 141 142 FIELDIANA: ZOOLOGY, VOLUME 47 an artificial system—based principally on tarsal segmentation—it did not provide a sound basis for studies on phylogeny, I have devoted considerable time to the tribal classification of the entire subfamily Aleocharinae with a view to proposing a system that is phylogenetically defensible, but in this monograph I must confine my attention to the dorylophiles. The classification of the genera of dorylophilous Aleocharinae in current catalogues has two major weaknesses: the expedient use of a few characters such as tarsal segmentation to place most of the genera; and, at the other extreme, the use of highly specialized abdominal characters as a basis for establishing small, often monobasic, tribes. Two examples may show how the current classification either brings together conver- gently adapted dorylophiles or separates alHed genera. In one in- stance, the large heterogeneous tribe Myrmedoniini includes genera of dorylophiles which I believe should be assigned to five tribes: Myrmedoniini (s.s.), Ecitocharini, Deremini, Dorylomimini, and Phyllodinardini. In another case, I propose to expand the tribe Dorylomimini to include 33 genera selected from about a dozen tribes of current catalogues. Expansion of the Dorylomimini—a tribe proposed by Wasmann for a few African genera but ignored by cataloguers—submerges a number of small tribes. The taxono- mists who studied and classified the dorylophilous Staphylinidae were either staphylinid specialists who adhered rigidly to an artificial tribal system, or non-specialists who had little acquaintance with free-living Aleocharinae. The former placed the dorylophilous genera in existing tribes on the basis of tarsal segmentation, while the latter tended to emphasize the highly specialized condition of the dorylophile abdomen and to propose new categories. The view that a tribe should be characterized by a community of characters was largely overlooked by specialists and non-specialists alike. The literature on the dorylophiles is largely devoted to descrip- tions of new genera and species and scant attention has been given to problems of phylogeny, evolution, and zoogeography. Between 1889 and 1925 Wasmann laid the foundation of our present knowl- edge of the dorylophiles, as he received and described many new forms from Africa and the Americas. He also wrote extensively about adaptive features of dorylophiles and proposed such concepts as amical selection and symphilic instinct. Wasmann was a strong proponent of "ameisenmimikry" and believed that mimicry is an adaptation designed to deceive the host ants and to thus insure admission of the mimics to the colony. Wheeler disagreed with Wasmann on his concept of mimicry and participated in a heated SEEVERS: STAPHYLINID BEETLES 143 controversy in which he and Heikertinger supported one viewpoint and Wasmann and Reichensperger another. Wasmann believed in the independent origins of the Old and New World dorylophile faunas. In a discussion of adaptational types (Wasmann, 1912a, p. 470) he stated, "... the genera which represent these types in the two hemispheres do not stand in any closer systematic relationship to each other. Their similarity, there- fore, rests upon convergence as the result of similar conditions for adaptation." In the course of the present studies, I have attempted to marshall the evidence, pro and con, that bears on Wasmann's proposition; this will be presented in later sections. At this point it may be stated that present evidence does not conclusively demon- strate that the army ant subfamily Dorylinae is a monophyletic group with a pantropical dorylophile fauna, or that, on the contrary, it is a polyphyletic group with independently derived dorylophile faunas. In an earlier work on the termitophilous staphylinid fauna (Seevers, 1957), I was able to show that there are several pantropical termite- termitophile interspecies systems, in refutation of assertions by both Wasmann and Warren that the Old and New World termitophile faunas were independently evolved. In recent years two studies on the dorylophilous fauna have been initiated and partially completed—one by Dr. David Kistner on the Old-World Pygostenini, and another by Dr. Carl Rettenmeyer on the New World ecitophiles. Kistner (1958) published a thorough revision of the Pygostenini and discussed the phyletic and host re- lationships of the genera of that tribe. He is continuing his research program on the Pygostenini and other dorylophiles in the course of several trips to Africa to study the ecology and behavior of these guests. Rettenmeyer's

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