FNZ 57 - Apoidea (Insecta: Hymenoptera) - Introduction
Donovan, BJ 2007. Apoidea (Insecta: Hymenoptera). Fauna of New Zealand 57, 295 pages.
(
ISSN 0111-5383 (print),
;
no.
57.
ISBN 978-0-478-09389-6 (print),
).
Published 07 Sep 2007
ZooBank: http://zoobank.org/References/B2070E05-13B6-4CBF-9A0A-0ACE40FA4796
Introduction
The Apoidea, or bees, were defined by Michener (1965) as being basically sphecoid wasps that use pollen as a protein source rather than insects or spiders. Some of the primitive bees are very similar to the sphecoid wasps, but are distinguishable by the presence of at least a few branched hairs on the body, by having the hind basitarsi wider than the following segments, and by the absence of a strigilis on the hind legs. However, because of the close physical similarities between sphecoid wasps and bees, some authorities have placed bees with the sphecids within the superfamily Sphecoidea (e.g., Brothers 1975, Lomholdt 1982, Alexander 1992). Conversely, Gauld & Bolton (1988) believed that the Sphecidae and Apidae should be grouped together in the Apoidea. However, Cardale (1993) retained Apoidea as a superfamily for bees of Australia, and Harris (1994) retained Sphecoidea as a superfamily for sphecid wasps of New Zealand. Michener (2000), in a major work on the bees of the world, believed that similarities between sphecid wasps and bees were so great they should all belong in the same superfamily, and that because a family-group name based on the generic name Apis antedates a name based on Sphex, the name of a bee-sphecoid superfamily should be Apoidea. Bees were confirmed as belonging to the Series Apiformes of Brothers (1975), and the sphecid wasps to the Series Spheciformes. For reasons given below, this revision of the bees of New Zealand retains the name Apoidea for bees, as defined by Michener (1965).
Bees have long been regarded as constituting a monophyletic unit, and Michener (2000) detailed 14 synapomorphies that demonstrate this. There is of course some overlap with characters of various groups of wasps, such as the utilisation by several species of the genus Trigona, subgenus Trigona, partially or exclusively, of carrion as a protein source instead of pollen, and conversely, the use of pollen by Masaridae (Vespoidea) instead of animal protein. The 14 characters also help to define the distinctiveness of bees from other insects. However, there are two other major characters not listed by Michener (2000) that further emphasise the unique nature of bees. These characters are not morphological, and are displayed by only a relatively small number of species, but I believe them to be none the less as valid as standard morphological characters as representative of the Apoidea as a whole. One is the widespread development of sociality among bees. Michener (2000) believed that of the seven families recognised by him, eusociality (where many individuals live intimately, there is division of labour, and in highly eusocial forms castes are morphologically differentiated) has evolved in the Halictidae and Apidae at least eight times, and probably many more. Several hundred species in the Meliponini (Apidae) alone are eusocial, with up to scores of thousands of individuals per colony. In contrast, according to Bohart & Menke (1976), sociality in Sphecidae (the sphecoid wasps) is developed only slightly. Representatives of several subfamilies may maintain nests over several generations, and in nests of Microstigmus comes up to 18 adults of both sexes and 18 cells with brood of all ages were present. However, there was no indication of caste differentiation. A second and very major character is the use by species of Apis of a dance ‘language’ by which information about distance and direction of food sources and nesting sites is transmitted between foragers (Frisch 1950). The dance language hypothesis has been challenged (e.g., Wenner & Wells 1990), but a new, comprehensive hypothesis which presents a resolution to the controversy, suggests that bees use the dance information more comprehensively than had hitherto been supposed (Donovan 2000). Some stingless bees (Meliponinae), of which there are at least several hundred species, have been reported to guide bees more directly to forage and to nest sites, using odours to mark pathways, but recently Melipona panamica has been found to possess the ability to indicate food location without using a scent trail (Nieh & Roubik 1995, 1998). The possession of a language by Apis and probably one or more Melipona is a feature otherwise unknown in the Arthropoda, and indeed elsewhere, apart from humans and possibly some great apes and cetaceans. I believe the possession of this character is a valid reason to justify the retention of the superfamily Apoidea for bees.
Bees of the world and New Zealand
Michener (2000) puts the number of described species of bees from throughout the world at about 17,000, and thinks that the total number of species could be about 30,000. He recognises 7 families, which when ranked from most primitive to most advanced are often presented in the following order: Stenotritidae, Colletidae, Andrenidae, Halictidae, Melittidae, Megachilidae and Apidae. Only 41 species of bees are established in New Zealand, and these belong to just 4 families, i.e. Colletidae: 28 species, Halictidae: 5 species, Megachilidae: 3 species, and Apidae: 5 species.