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Distribution of Afrotropical Kite Swallowtails

Why study Afrotropical kite swallowtails?

In this section we give our justification for making our study. We begin asking:

Why study butterflies?

Philosophers are extolled to 'know thyself!', and Alexander Pope wrote that 'the greatest study of mankind is man'. If similar advice were given to a biologist, it would have to be 'know thy species!' It is only through knowing what animal or plant you are investigating that you can understand its physiology, behaviour, ecology, conservation needs, and indeed all aspects of its biology. It is only through study of the species and its relationships that you can come to know it. By knowing its relationships with other species you can begin to make predictions about its biology or about the biology of its relatives. This, essentially, is taxonomy.

Alfred Russel Wallace, the great nineteenth century naturalist, and co-originator with Charles Darwin of the theory of natural selection, wrote, “When the naturalist studies the habits, the structure, or the affinities of animals, it matters little to which group he especially devotes himself; all alike offer him endless materials for observation and research”.

This alone — the human spirit of curiosity — justifies the study of the Afrotropical kite swallowtails.

'But,' Wallace continued, 'for the purpose of investigating the phenomena of geographical distribution and of local or general variation, the several groups differ greatly in their value and importance. … Pre-eminent among such groups are the diurnal Lepidoptera or Butterflies, whose extreme beauty and endless diversity have led to their having been assiduously collected in all parts of the world'. He goes on to note that the ' … wings of Butterflies, as Mr. Bates has well put it, serve as a tablet on which Nature writes the story of the modifications of species'.

Butterflies, and in particular the swallowtail butterflies of the family Papilionidae, are highly visible members of the invertebrate community. There are enough species to be interesting biologically, but not so many as to be overwhelming. They have been 'assiduously collected' and so there is — or should be — plenty of material on which to base the studies of geographical distribution and related phenomena. They also tend towards distinctive patterns and so are — or should be — readily identifiable by non-specialists including field workers and 'bare-foot' taxonomists. As such they make excellent 'indicator' organisms for ecological studies.

Why Afrotropical kite swallowtails?

Our long-term objective is to contribute to international efforts to understand the classification of the swallowtail family, Papilionidae, by tackling a significant part of it: the Afrotropical fauna.
Kite swallowtails of the genus Graphium form an important component of the Afrotropical papilionid fauna. (See higher classification for a more detailed account of the Papilionidae and their relationships.)

Three genera of the Papilionidae are represented in the area:

  • Pharmacophagus includes just one species, P. antenor, and is confined to Madagascar.
  • About 56 of the 200 or so species of the worldwide genus Papilio occur in the region (Ackery, Smith and Vane-Wright, 1995).
  • Graphium is more amenable to study, with about 40 species in the Afrotropical region and another 60 in the rest of the Old World tropics. The Afrotropical species were believed to be a 'natural' (monophyletic) group making them a well-defined subject for study (but see our results).

It was these considerations that led us to begin our study. We wanted to unearth as much information about the group as possible, whether that information was in the form of written accounts in the existing literature, or in the form of the data on the thousands of specimens in The Natural History Museum and many other museums we were able to visit or from which we were able to borrow material. Such collections have been described as 'three-dimensional databases'.

To make sense of all this information we needed to be able to put it in the context of the butterfly species themselves and their relationships — know thy species!

Why did we want the information?

In the light of the pressures humans are putting on the natural world — the biodiversity crisis — and following the 1992 Rio summit, governments and international organisations are beginning to take on board the 'know thy species' message. There have been many initiatives designed to draw up inventories of organisms at local, national and international level. These projects are all data hungry and need to start with suitable indicator groups. For the reasons first suggested by Wallace and elaborated above, butterflies are an eminently suitable group.

Our study has been designed to collate data in a way that it could be used to support such international initiatives as:

  • GBIF, the Global Biodiversity Information Facility
  • GloBIS, the Global Butterfly Information System
  • GART, the Global Butterfly Species Register (Globales Artregister Tagfalter).

Nearer to home we wanted to provide data to a remarkable system developed by our colleague in the Department of Entomology, Dr Paul Williams, namely WORLDMAP. WORLDMAP is a software system for exploring geographical patterns in relationships, diversity, and rarity from large biological datasets to help provide rational ways of assessing conservation priorities. Already we have been able to feed our data into Paul's system and examine the patterns of species distribution of the Afrotropical Graphium and to compare them with those of birds.

Those, then, are our reasons for studying Afrotropical kite swallowtails. In order to focus our study, we confined ourselves to the following questions:

  • How many species of Afrotropical kite swallowtails are there?
  • Are the Afrotropical Graphium a natural group, including all Afrotropical species and no others? In other words, is the subgenus Arisbe monophyletic?
  • Do the swordtailed species form a natural, monophyletic group?
  • Are the non-swordtailed species monophyletic?

In the accompanying pages we give a summary of our results, together with a checklist of the species and subspecies we recognise. You can read about our methods, and we give an account of the place of the kite swallowtails in the higher classification of butterflies. There is also a page of references and links. Finally there is an interactive database of the butterflies' distributions. We hope that each page is sufficiently self-contained for them to be read in any order.