The Nepticulidae (Leptdoptera) of Canada
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THE NEPTICULIDAE (LEPTDOPTERA) OF CANADA CHRISTOPHER WILKINSON Department of Animal Systematics and Zoogeography Vrije Universiteit Amsterdam, Netherlands M. J. SCOBLE Transvaal Museum Pretoria 0001, R.S.A. MEMOIRS OF THE ENTOMOLOGICAL SOCIETY OF CANADA - NO. 107 Pubtished bylHE ENTOMOLOGICAL SOCIETY OF CANADA, OTTAWA K1Z 7K9 1979 To My Friends and Colleagues of the Biosystematics Research Institute, Ottawa, Canada (C.W.) CONTENTS Pacs Abstract I Introduction I Methods L List of Abbreviations . Acknowledgments . Taxonomic History Family NEPTICULIDAE ... 8 Gerus Stigmella t2 't3 GenusEctoedemia . .. GenusODrzssa .... 98 Gents Glaucolepis r02 General Discussion and Summary 108 References 115 Index to Genera, Species, and Subspecies . .. r29 Plates l.Therosaefoliellagtotp-mlnes... 'p'119 2. The crataeg{olielta gtovp-mines . ' p' 120 3. The saginella group-mrnes " " " ' p' l2l 4. The corylifoliella group-mines . ' p' 122 5. Thebifasciella group andquercipulchella group-'mines . " " p' 123 6. Ectoedemia argyropeza, E. clemensella, E. platanella-mines . ' p' 124 125 7 . Ectoedemia rubifulietla, E. ulmella, E. quadrinotata, Glaucolepis saccharella-mines - . ' . p' 8. The rosaefoliella group a d the cratae7ifotiella gtoup-imagines . ' ' ' ' ' ' p ' 126 9. The saginella group, the corytifolielta group, and thebifuscielta group-imagines " " " " p' 127 lO. The procrastinella group, Ectoedemia canutus , E. Iindquisti, E. rubifulielln, E. quadrinotata Obrissaochrefasciilla,'O. sericopeza,Glaucolepis saccharella-imagines . " " p' 128 THE NEPTICULIDAE (LEPIDOPTERA) OF CANADA Cur.tstopur:,n WtLxtNsoN aNp M. J. ScosI-E, Abstract A taxonomic revision, including descriptions, diagnoses, and bibliographies, is given of the genera and species of the family Nepticulidae (Lepidoptera) so far collected in Canada. In addition, extensive material from the U.S.A. and a number of specimens from Europe have been examined. Five new species and two new subspecies are described. Notes on the biology of the species have been collated from rearing records, label data, and the relevant literature. With one exception all existing types have been examined and, in addition, a number of types designated. A major f'eature of this work is a study of the genitalia of the moths never befbre undertaken extensively on the North American Nepticulidae. These structures give valuable diagnostic features and are of fundamental importance in the provision of modern descriptions and keys. As genitalia characters are thought to be the best taxonomic indicators of relationships between species in the Nepticulidae, the species-groups proposed have been mainly defined on these structures. The confusion over the nomenclature of the family name is discussed. Taxonomic histories of the genera are given and one generic synonymy is made. Taxonomic problems are discussed in relation to distribution and food-plant choice. The hoslplant associations of the family are reviewed, with reference to the mining habits of the Iarvae. A priori use of host-plant data in the taxonomy of the Nepticulidae is found to be limited. However, the proposed species-groups illustrate a general conclusion that related species tend to feed on plants that are themselves taxonomically related. INTRODUCTION The Nepticulidae is a cosmopolitan family of microlepidopteran Monotrysia whose larvae mine the parenchymatous tissue of plants or occasionally induce the formation of galls on the petioles of leaves. Most species are leaf-miners, but some mine bark and others fiuits. Nearly all the work on the systematics of the genera has been carried out in the Nearctic and the Palaearctic. However, because the entomologists of these respective regions worked rather independently of each other, there have been certain inconsisten- cies in the generic placement of a number of species. The Canadian species are regarded in this work as falling into four genera: Stigmella Schrank, Ectoedemia Busck, Obrussct Braun, and Glaucolepis Braun, principally on the basis of wing venation, genitalia, distribution, and also biology where known. Some changes in nomenclature are the result of a critical review of the taxonomic history. These are primarily the subject of a separate paper (1978) but the main conclusions are summarized here. The aims of this study are'.To list, describe, andprovide modern fteys of the genera and species of the Nepticulidae so far known from Canada, and to include any new species and subspecies. The work aims to provide descriptions of the external features using high intensity illumination to give both the ground colour and the reflections of all the species considered. The genitalia are used extensively to provide taxonomic characters for the descriptions. Leaf-mine pattern and, to a certain extent, choice of food-plant give additional diagnostic features. Although this study deals primarily with the Canadian members of the family, it is aimed to incorporate specimens collected in the U.S.A. of species which occur in both countries. This additional material comes largely from the Annette Braun collection (deposited in the Academy of Natural Sciences, Philadelphia) which includes most of the types of the North American Nepticulidae. To resolve certain problems of the taxonomic treatment of the group. Clemens and Chambers commenced the work on the svstematics of the Nearctic Nepticulidae last l.n,u.r. In severar and, on a number or occasions, described'"JJ. species from";#ffi';"';;"ffiiar the mines alone. The latter are often of little value in the differentiation of closely related species. Braun reared imagines of most of Clemens' species and also a large number of new ones. However she did not use genital characters, but relied largely on external colouration and form of the mines. In this study the genitalia (believed to be less affected by environmental vicissitudes) are used extensively in indicating relationships as well as providing good diagnostic characters. To relate the taxonomy of the family in the Nearctic to work carried out in the Palaearctic. The cosmopolitan nature of the family is clearly reflected by the distribution of the genera. Stigmella, Ectoedemia, and Obrussa are all represented in Europe as well as North America. There is considerably more literature on the European Nepticulidae, including studies of the genitalia, than on the North American representatives. However, although European workers have made a number of references to the Nearctic species, they have studied only a few of them at first hand. Consequently a further purpose of this study is to make changes, where necessary, in nomenclature and to suggest treatment for the much disputed supra-specific ranks. This includes examining a number of closely related European species and, in two cases, species occurring in both this region and North America. To collate from label data, rearing records and the literature, notes on the biology of each species and to discuss host-plant relationships. METHODS The wing measurements give the alar expanse in millimeters. The moths were measured from the middle of the thorax to the wing-tip and this figure was doubled to give the full expanse. The very small size of these insects can cause problems in setting and any buckling in the wings makes accurate measurements impossible. As some specimens were not well mounted, we have only measured those which give a relatively accurate figure. The genitalia were figured by means of a drawing tube fitted to a Wild M20 microscope. The scale represents 1/10 mm unless otherwise indicated. The male genitalia are presented from a ventral aspect; the aedeagus is represented separately from the capsule. As the valves are curved, in many cases the back and front are represented by thick lines on opposite sides. Occasionally a lateral view of a valve is given. Black and white photographs of imagines and mines are provided. The extremely small size, and lighting difficulties, have proved problematic in producing satisfactory prints of the imagines. However, to a certain extent, these photographs illustrate the variation and convergence within the species examined. With certain exceptions, each species is described, and provided with a 'DIAGNOSIS': this is differential. The exceptions include taxa which are not sufficiently different from others to warrant repeating a full description. Instead 'DIAGNOSTIC FEATURES' are given. Single specimens showing variation not falling within the confines of a given species description are separated as specimens a, b, c, etc. The dates given in the 'SPECIMENS EXAMINED' are those of the emergence of the imagine, not the date on which the tenanted, mined leaves were collected. A section entitled 'BIOLOGY' follows the more formal taxonomy, in which additional information, collated from mined leaves, rearing records, and relevant literature is given. A number of species-groups are proposed in this study. We are agreed with Johansson (191 l) that to split the Nepticulidae into a large number of genera would be WILKINSON AND SCOBLE: THE NEPTICULIDAE OF CANADA J of little value. The more informal method adopted indicates relationships between species within a given group yet prevents the taxonomy from becoming unwieldy. Throughout this study the International Code of Zoological Nomenclature has been followed. Tvpp MerEntaL. Besides selecting lectotypes and paralectotypes from syntypes, four neotypes have been recommended. In all cases the species were first described by Clemens in the last century from leaves mined by the larvae.