Evolution and biogeography of native Hawaiian Hylaeus bees (Hymenoptera: Colletidae)

Abstract

The only bees native to the Hawaiian Islands form a single clade of 60 species in the genus Hylaeus. The group is understudied and relatively poorly known. A data set consisting of 1201 base pairs of the mitochondrial genes cytochrome oxidase I and II and tRNALeucine, and 14 morphological characters was used to construct a phylogenetic tree for 48 of the 60 known species. Genetic variation was high, including amino acid changes, and a number of species showed evidence of heteroplasmy. Tree support was low due to high levels of homoplasy. Biogeographical analysis using DIVA indicates that early radiation took place on the island of Hawaii. This places an upper age limit of only 0.4-0.7 Myr for the group, an unusually short time for such a large radiation. Moreover, it is an unusual biogeographical pattern among the Hawaiian biota.

Bees in the Southwest Pacific: Origins, diversity and conservation

“…As is the case in Fiji, the majority of this diversity consists of the genera Lasioglossum and Megachile, with ten and seven species, respectively. Within Samoan Lasioglossum, the 'explosive' endemism seen in Homalictus has been likened to the 60 species of Hylaeus in Hawaii (Krombein 1950;Magnacca and Danforth 2006). Samoa also harbours putative social parasites in this subgenus (Michener 1965) which, due to their highly modified structure and characteristics, Perkins and Cheesman (1928) originally placed in a separate genus Echthralictus.…”

“…Nevertheless, hypotheses on the biogeography of native bees in the Pacific have been numerous. The 60 species of Hylaeus of Hawai'i, the only bees native to the island group, form a single clade thought to have diversified from a single coloniser some 0.5 Mya that expanded into open niches (Magnacca and Danforth 2006). The recent volcanic origin and isolation of the island group, in addition to the closest relatives to the subgenus predominantly in Japan, but also China and Europe, provides support for long-distance dispersal ability in small bees.…”

“…The species has been recorded numerous times from the Fijian islands (Cockerell 1909;Turner 1919;Fullaway 1957;Evenhuis 2007), yet remains unrecorded in other southern Pacific islands despite the genus having diversified rapidly in the northern Pacific (Magnacca and Danforth 2006).…”

Insect Biodiversity in the Palearctic Region

“…The insect fauna of the Palearctic is slightly depauperate at the order, family, and genus levels (compared to most other regions) but it has high species richness; that is, the number of higher taxa with only a single species in the Palearctic is relatively low and the relative number of species per higher taxon is large. In this regard, it is similar to island faunas characterized by a small number of introductions that were followed by extensive species-level radiations (Magnacca and Danforth 2006). The Palearctic and Oriental regions have about the same number of species of flea beetles (Chrysomelidae: Alticini) (about 3000, although the Oriental fauna is much less known), but differ sharply in generic diversity, with about 60 genera in the Palearctic and 220 in the Oriental.…”

First records of Hylaeus (Paraprosopis) pictipes Nylander, 1852 (Hymenoptera: Colletidae) in North America

“…punctatus (Brullé, 1832), have recently become established in North America, particularly in urban areas, and their ranges are expanding (Snelling 1983;Ascher 2001;Ascher et al 2006;Sheffield et al 2011;Ksiazek et al 2014;MacIvor & Packer 2015). Hylaeus (Indialaeus) strenuus (Cameron, 1897), an Indian species, has become established in Hawaii (Magnacca et al 2011(Magnacca et al , 2013). Another exotic species, H. (Hylaeus) communis Nylander, 1852, with potential to spread widely in North America, has just been documented in Canada (Martins et al 2017).…”