Origin and Evolutionary History of the Honeybees Apis

The fossil record, in general, presents a severely limited and unrepresentative sample of past life. Only about 130 000 fossil species, representing less than 3% of the probable total number of organisms that have ever lived, have been described and named. This dearth of material is a consequence of the fossilization process: not all organisms have; an equal chance of becoming fossilized, and not all geological environments are equally favourable to the production of fossils. About 12 000 fossil insect species are known, the oldest being of Devonian age (the major divisions of geological time are presented in Table 1). The scarcity of fossil specimens, in this largest class of animals, reflects the fact that insects generally occupy habitats that are not conducive to their preservation as fossils. But despite its inherent deficiencies, the fossil record does provide valuable information on the histories of certain insect groups, among them the bees. Preservation of fossil bees has often been excellent. Many specimens have come to light, such as those embedded in amber, with important morphological characters well displayed, a circumstance permitting the determination of systematic and evolutionary relationships with some measure of confidence. The present article summarizes available evidence, from the fossil record and other sources, for the probable origin and evolution, in geological time, of one particular group of bees: members of the honeybee genus Apis. It represents a first attempt to bring together the sometimes ambiguous and conflicting findings from a rather scant literature on the subject, and from them to present a reasonably coherent and plausible picture of honeybee evolutionary history