1978] 
Burnham — Social Insects in Fossil Record 
119 
Miocene 
By the Miocene, the bee fauna is essentially modern. In Chiapas 
Amber from Mexico, bees have been discovered that are so similar 
to an existing Neotropical species that they have been assigned to 
the same subgenus, Trigona ( Nogueirapis ), and are scarcely different 
at the specific level (Wille, 1959). Fujiyama (1970) mentions the 
discovery of a fossil bee in a Japanese Miocene deposit and states 
that, “There is no room for doubt that this is a species of honeybee.” 
A review of the fossil record reveals the following about the 
evolution of the bees. 1) We know that the Early Oligocene fauna is 
a mixture of primitive and advanced genera, although it appears to 
be dominated by fairly advanced species. By the end of this epoch, 
the fauna is modern in overall character. 2) We know that sociality 
had clearly arisen by the end of the Oligocene, and possibly much 
earlier. And 3) by the Miocene, the bees were virtually indistinguish- 
able from the bees of today. Six families of bees are represented in 
the Oligocene: including the phylogenetically advanced Apidae with 
six genera and 22 species. Such diversity of relatively advanced bees 
is indicative of either a much longer history of the group than is 
evidenced by the fossil record, or a fairly short history characterized 
by the rapid speciation and explosive radiation of the group. 
The bees are clearly derived from the spheciform wasps, al- 
though nothing is known about the nature of this sphecid ancestor 
(Wilson, 1971; Michener, 1974). In 1964, just prior to his death, F. 
J. Manning was investigating a sphecid from the Jurassic beds of 
Lerida Province, Spain, which “he thought might be (or be closely 
related to) the ancestor of the bees” (Zeuner and Manning, 1976, p. 
155). This would be an astounding find if true, and it is unfortunate 
that nothing more is known — either about the specimen or about 
Manning’s reasons for thinking it ancestral to the bees. 
The distinction between the Sphecoidea and the Apoidea is 
sufficiently subtle as to make determinations of fossil compressions 
extremely difficult. The presence of plumose hairs and enlarged 
basitarsi, characters which are important apoid features, rarely 
survive preservation unless the insect is preserved in amber. 
The origin of the bees remains a subject of much speculation. It is 
believed that “insect-plant interactions played a key role in the 
origin of the angiosperm flower and component structures” (Hickey 
