FNZ 57 - Apoidea (Insecta: Hymenoptera) - Diagnosis, origin and biogeography
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
Diagnosis, origin, and biogeography
DIAGNOSIS FOR NEW ZEALAND BEES
Adults: Head orthognathous; compound eyes large; females with 12 antennal segments, males with 13. Pronotum immovably joined to the mesothorax; posterior lateral margin with a rounded extension, the pronotal lobe, which covers the spiracle and which is well separated from the tegula. First true abdominal segment fused to the metathorax so that the pro-, meso-, and metathoracic segments plus the first true abdominal segment or propodeum, constitute the mesosoma. A constriction posterior to the propodeum separates the mesosoma from the remaining abdominal segments, which constitute the metasoma. Hind leg without a cleaning pecten or brush in a depression basally on inner side of basitarsus (present in sphecoid wasps). Hind basitarsus wider than following tarsi (scarcely wider in sphecoid wasps). At least some body hairs branched, although often difficult to distinguish in Hylaeus, and particularly Euryglossina (hairs simple in sphecoid wasps). Females (except for Hylaeus, Hyleoides, and Euryglossina, which carry pollen internally, and queens of Apis) with areas of hairs modified to form pollen-carrying scopae or corbiculae (absent in sphecoid wasps). Michener (2000) pointed out that the lower face of nearly all bees is dull, whereas that of most sphecoid wasps has short golden or silvery hairs that glitter in the light.
Eggs: Elongate, tubular, gently curved, laid in a cell or cup, on pollen/nectar, or if not laid on pollen/nectar, adult bees later supply food to the larvae.
Larvae: Soft, white or near-white, and legless; growth often rapid; shed skins very flimsy and therefore difficult to see, but probably about 4 moults.
Prepupae: White or near-white, legless.
Pupae: Initially pearly white, rapidly darkening as adult features mature within pupal skin.
ORIGIN OF NEW ZEALAND BEES
The 41 species of bees present in New Zealand can be divided into 4 groups according to their origin.
- Endemic, which occur only in New Zealand: 27 species (all 18 species of Leioproctus (although the status of L. otautahi is uncertain), 6 of the 8 species of Hylaeus, and 3 of the 4 species of Lasioglossum).
- Indigenous, which also occur in Australia and which originated from there, but which probably reached New Zealand without human involvement: 1 species (Lasioglossum cognatum). This species is ground-nesting, so it is possible that nests containing immatures and/or adults reached New Zealand in ballast in sailing ships. However, the smaller size of bees from New Zealand suggests the species has been in New Zealand for sufficient time for the development of some divergence from the Australian population, which in turn suggests adults must have somehow crossed the Tasman Sea, perhaps through being caught in a rare cyclonic windstorm, a long time ago.
- Adventive, assisted inadvertently by humans: from Australia, Hylaeus asperithorax, H. perhumilis, Hyleoides concinna, and Euryglossina proctotrypoides: from Europe originally but which has colonised other areas including parts of North and South America and the Canary Islands, Anthidium manicatum. The 4 species from Australia could have crossed the Tasman Sea unaided as presumably did Lasioglossum cognatum, but because they construct their nests in blind tunnels in plant material, there may be a greater possibility that whole nests were carried across the Tasman Sea in timber or plant stems, by ships or aircraft. Similarly nests of A. manicatum which are constructed in blind cavities in plant and other materials could have reached New Zealand from any part of its extended range.
- Imported, purposely from the Northern Hemisphere by humans for economic reasons: 8 species (Nomia melanderi, Osmia coerulescens, Megachile rotundata, Bombus terrestris, B. hortorum, B. ruderatus, B. subterraneus, and Apis mellifera).
Endemic and indigenous bees are native to New Zealand and total 28 species, and adventive and imported bees are introduced to New Zealand, and total 13 species.
BIOGEOGRAPHY OF NEW ZEALAND BEES
Colletidae
This family is most abundant and most diversified in temperate parts of Australia and South America (Michener 2000). There are 5 subfamilies, of which 3, the Colletinae, Hylaeinae, and Euryglossinae, are represented in New Zealand.
Colletinae. For the world, 17 genera are listed in Colletinae, and formerly these were divided into 2 tribes, the Colletini and the Paracolletini. However, due to a number of factors, including the possession of overlapping characters between some groups previously thought to be distinct, and in particular the large number of Australian species which are yet to be described, the allocation of genera to tribes has been abandoned. The genus Leioproctus is huge, and has 33 subgenera, with only the subgenus Leioproctus common to both South America and the Australian subregion.
There are about 125 specific names in the subgenus Leioproctus, of which Cardale (1993) listed 113 from Australia. The remaining species occur in New Guinea, Misool (an island west of New Guinea), Lord Howe Island, Tasmania, and New Zealand. A single species from Brazil differs in several characters that might place it outside the subgenus. The type species of the subgenus is Leioproctus imitatus Smith from New Zealand, by designation of Cockerell (1905a). In this revision, 11 species from New Zealand, all of which are endemic (apart from possibly L. otautahi), are assigned to the subgenus Leioproctus. Because the bulk of species in the subgenus Leioproctus occur in Australia, there seems no doubt that the New Zealand species are derived from Australia.
The subgenus Nesocolletes occurs only in New Zealand, so the 7 species assigned to it in this revision are endemic. Most species possess characters that clearly separate them from the subgenus Leioproctus, such as a long malar space, and in profile a declivous propodeum, but a short malar space and/or a slightly rounded propodeum in a couple of species suggest an origin from the subgenus Leioproctus. Whether the origin is from the subgenus Leioproctus in New Zealand, or from the subgenus in Australia, is unknown.
Hylaeinae. According to Michener (2000), this subfamily is world-wide, but is most abundant and diversified in the Australian region. There are 9 genera, of which Hylaeus with 46 subgenera is by far the largest. Hylaeus occurs almost everywhere, and all 8 species in New Zealand belong to the subgenus Prosopisteron. This subgenus has 76 named species (Michener 2000), of which 55 are listed from Australia (Cardale 1993). Six of the 8 species are endemic, and 2 are adventive. There can be little doubt that the progenitors of the endemic species originated in Australia.
Houston (1975) listed 8 species of Hyleoides from Australia, and 1 specimen from Lord Howe Island. There can be no doubt that H. concinna, which occurs in New Zealand and which is otherwise found only in Australia, originated from Australia.
Euryglossinae. Historically this subfamily was known only from Australia, including Tasmania, where about 348 species are known in 15 genera, but according to Michener (2000), 1 species has been taken in South Africa, and 1 species is established in New Zealand (Donovan 1983a). Several species also occur in New Caledonia (Donovan pers. obs.) The New Zealand species is conspecific with an Australian species, so undoubtedly the New Zealand species originated from Australia.
Halictidae
Some bees of this family are sometimes referred to as sweat bees because they will sup moisture from skin on hot days. In temperate areas the numbers of individuals can be greater than other bees except honey bees. There are 4 subfamilies, of which 2, the Nomiinae and the Halictinae, are represented in New Zealand.
Nomiinae. The 11 genera in this subfamily are centred in the palaeotropical and Old World austral regions, with just 2 genera in North America. There is just 1 introduced species, Nomia melanderi, the alkali bee, which was imported from the United States as a manageable pollinator of lucerne seed crops.
Halictinae. This is an enormous, widely distributed group, of which some species and numbers of individuals can be common. There are 2 tribes, with only the Halictini represented in New Zealand and Australia. There are 12 genera in the Eastern Hemisphere, with just Lasioglossum in New Zealand. In this genus in Australia there are 8 subgenera and about 250 species. Two subgenera and 4 species occur in New Zealand. Three species, which are in the subgenus Austrevylaeus, are endemic. There are 6 other described species in this subgenus in Australia, and 13 others are known (Michener 2000). Presumably the ancestor(s) of the New Zealand species was/were Australian. There are 134 species in the subgenus Chilalictus, with a distribution of Australia including Tasmania, at least 1 species in New Caledonia, and Lasioglossum (Chilalictus) cognatum present in both Australia and New Zealand. This species is ground nesting, so it seems unlikely that it reached New Zealand as immatures within nests. Adults probably crossed the Tasman, and could have done so at any time unassisted by humans, so this species is here regarded as indigenous.
Megachilidae
This family of leafcutting bees is widely distributed. There are 2 subfamilies, of which the Megachilinae is divided into 5 tribes. The Osmiini, Anthidiini and Megachilini are each represented in New Zealand by 1 species. The species in Osmiini was purposely imported from Europe for pollination of red clover, and the species in Megachilini was purposely imported from North America for pollination of lucerne, but the species in Anthidiini is very recently adventive from an extended foreign range.
Apidae
As conceived of by Michener (2000), this is a hugely diverse family, which has been divided by many other workers into a range of families and many subfamilies and tribes. Two tribes of Apinae are represented in New Zealand. The Bombini are distributed primarily over the Northern Hemisphere and also Central and South America, and 4 species have been imported with the purpose of improving the pollination of red clover. The Apini is represented by the European or western honey bee, which was imported for honey production.