INTRODUCTION

This part of The Moths of Borneo includes accounts of the families Cossidae, Metarbelidae, Ratardidae and Limacodidae. It is the first part of the series and therefore an appropriate place to include a key to world macrolepidopteran families that will serve the whole series and complement An Introduction to the Moths of South East Asia by Barlow (1982).

All ‘macrolepidoptera' belong to the Suborder Ditrysia, members of which have the venation of fore- and hindwings dissimilar and possess a female genital opening (ostium) on sternum 8 that is separate from the ovipositor on sternum 9.

This part contains the families attributed to the superfamily Cossoidea by Brock (1971), though Common (1970) placed the Limacodidae in the Zygaenoidea. It is not feasible in this work to throw any further light on this disagreement but the reader should be aware that the higher classification of the Lepidoptera is still in a state of flux and changes must be expected in the light of future work.

The families treated here, with the exception of the Ratardidae, all contain many species of economic importance, with wood, stem and bark borers in the Cossidae and Metarbelidae and numerous serious defoliators of plants of economic importance in the Limacodidae.

Most of the material referred to in this series was accumulated during three major surveys, two by the author in the Kinabalu and Mulu National Parks of Sabah and Sarawak respectively, and the other over a period of years by Lt. Col. M.G. Allen and associates in Brunei. Details of the first two surveys, accounts of the various localities sampled and analyses of the ecology and habitat preference of the species can be found in Holloway (1970, 1984b). Accounts of the Brunei collecting localities are given by Allen (1981), Harman (1981) and Cassidy (1982). There is some inconsistency in the vegetation zones recognised in these references and on label data quoted for specimens in the main text. The broad categories referred to by Holloway (1984b) will be adopted here.

KEY TO THE FAMILIES OF MACROLEPIDOPTERA AND TO SOME SUBFAMILIES

Although this series is restricted to macrolepidoptera found in Borneo, a key to all world macrolepidoptera families is presented below as there is no guarantee that some at least of the non-Oriental groups will not ultimately be collected in South East Asia. Families occurring in Sundaland are indicated by heavy type, and macrolepidoptera by capitals.

The key is a modified version of one used in the annual Commonwealth Institute of Entomology taxonomy courses and it is hoped that a key to all Lepidoptera and notes on the families of economic importance can be published as a manual in the near future.

The key has been constructed with a view to enabling an inexperienced worker to place most specimens he will encounter to family in most cases.

Readily appreciable characters have been used where possible though harder and more reliable characters may be available; the latter, such as characters of thoracic-abdominal articulation, usually require preparatory work and dissection that may partially destroy the specimen. Even so, some of the characters used here are hard to appreciate. The tympanal organs in Noctuoidea and Geometroidea are best studied initially in fresh material which is malleable and where the tympanum shows up clearly as a nacreous or skinlike opaque membrane.

Characters of wing venation can be studied better if a wetting agent such as absolute alcohol or ethyl acetate is applied. The wings then increase in transparency and the veins can be seen if the wing is illuminated from behind and viewed under a microscope.

A number of the venation characters used recur from superfamily to superfamily and may reflect differences in flight mode and mechanics rather than any phylogenetic relationship. For example M
2 may arise from nearer the cubital angle of the cell of each wing than the radial angle more frequently in deep-winged moths, and from nearer the radial angle in narrow-winged moths.

Similarly, antennae with swollen, clubbed or hooked tips occur in a wide range of families, such as Sphingidae, Sematuridae, Noctuidae (Agaristinae, Cocytiinae), Arctiidae (Ctenuchinae), Castniidae, Zygaenidae, Papilionoidea and, slightly, Callidulidae. The common factor is the day- flying habit and one must presume that the possession of a pair of solid objects anterior to the eyes provides some sort of visual information: the function could be for range-finding or measuring. This is evidently a case of evolutionary convergence.

Opinions differ on superfamily divisions and also on the status in the hierarchy of some groups or their assignation to higher categories (Brock 1971; Common 1975; Minet 1983; Heppner 1984a). This key tends to follow broad concepts, i.e. to ‘lump' rather than ‘split'. Superfamilies may be identified by the ending -OIDEA, families by the ending -IDAE and sub- families by the ending -INAE.

There are very few keys available that will permit assignation to family of a lepidopteran from any part of the world. Common's (1970) key concentrates on the Australian fauna. That by Janse (1932) is much more comprehensive but the familial nomenclature requires considerable updating. This key draws from several sources and includes observations drawn from the experience of the author, primarily from the Old World tropical fauna. It is no doubt far from perfect and the author would be grateful for indications of error and suggestions for improvements.

Click here for a guide to wing venation for reference when using the key .




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