Hylaeus (bee)

The genus of bees consists of generally small, black-and-yellow or black-and-white wasp-like species. The resemblance to wasps is enhanced by the absence of a scopa, which is atypical among bees. The body form of this genus is described as hylaeiform (slender); the hairs inconspicuous without magnification; and scopa inconspicuous or absent. Males have an intermediate glossal shape with a small to distinct median apical glossal point. Hylaeus Subgenera At least 44 subgenera of Hylaeus are known in the world. These have been categorized geographically as follows by Ikudome (1989): • Australasian Region (19 subgenera): Analastoroides, Edriohylaeus, Euprosopellus, Euprosopis, Euprosopoides, Gnathoprosopis, Gnathoprosopoides, Hylaeorhiza, Hylaeteron, Laccohylaeus, Macrohylaeus, Meghylaeus, Planihylaeus, Prosopisteroides, Prosopisteron, Pseudhylaeus, Rhodohylaeus, Spearhylaeus and Xenohylaeus. • Palearctic Region (12 subgenera): Abrupta, Dentigera, Hylaeus, Koptogaster, Lambdopsis, Mehelyana, Nesohylaeus, Nesoprosopis, Paraprosopis, Patagiata, Prosopis and Spatulariella. • Nearctic Region (7 subgenera): Cephalylaeus, Hylaeana, Hylaeus, Metziella, Paraprosopis, Prosopella and Prosopis. • Holarctic Region (3 subgenera): Hylaeus, Paraprosopis and Prosopis. • Oriental Region (5 subgenera): Gnathlaeus, Hoploprosopis, Nesoprosopis, Nesylaeus and Paraprosopis. • Ethiopian Region (4 subgenera): Alfkenylaeus, Cornylaeus, Deranchylaeus and Metylaeus. • Neotropical Region (4 subgenera): Gongyloprosopis, Hylaeana, Hylaeopsis and Prosopis. ==Distribution and status==

A significant diversity of Hylaeus is found in Hawaii — approximately 64 species are recorded as living there. Hylaeus are the only bees considered native to the islands and most of those are unique to the island chain; the diversity of this genus is far greater in Hawaii than in all of mainland North America. Many of them are species of concern, and some recorded there are possibly extinct. For example, H. finitimus was last collected 100 years ago, and only ever seen on the island of Kauaʻi. The Hawaiian bee population and diversity is somewhat fluid — within the past ten to twenty years several Hylaeus species have been found and identified on the islands as new to science. North America America There are currently an estimated 130 species of Hylaeus in America. Several species have been accidentally introduced to the country. This includes: Hylaeus leptocephalus found throughout the country; Hylaeus hyalinatus found in urban New York, New Jersey and Pennsylvania; Hylaeus punctatus found in central California, Mid-Atlantic states, the Chicago region and Denver area; and Hylaeus (Prosopis) variegates in the greater New York city region. One masked bee of interest in the country is Hylaeus lunicraterius. This bee is only recorded at the Craters of the Moon National Monument, Idaho. Little is known about its biology, however it is believed to nest in the crevices and holes in the lava flows. Hawaiian Islands A single clade of 64 known Hylaeus spp. are native to Hawaii. Phylogenetic evidence suggests that the first Hylaeus species arrived on the island of Hawaiʻi between 0.5 and 0.4 million years ago. From here, it is believed that descendants of the initial (presumed ground-nesting) colonist separated in order to specialize in the different ecological niches available. This included coastal and dry forest strands (H. longiceps and H. anthracinus); mid-elevation and montane dry shrubland strands (H. difficilis); cleptoparasite strands (H. inquilina); and wet and mesic forest wood-nesters. After this divergence, it is believed dispersal to other Hawaiian Islands occurred. it can be calculated that the minimum speciation rate for Hylaeus on the island of Hawaiʻi is 9.23 species per million years. In 2024 a new species, Hylaeus paumako, was discovered on the island Molokaʻi. Hawaiian Hylaeus species include five known cleptoparasitic species. These are the only known cleptoparasitic colletids. Australasia New Zealand 8 species of Hylaeus are known in New Zealand. All of these species belong to the subgenus Prosopisteron. 6 of these species are endemic. Endemic species of Hylaeus are divided into two groups based on a distinctive feature: the form of the apex of the 8th metasomal sternum of males. Hylaeus agilis and H. capitosus have a rounded apex, while H. kermadecensis, H. matamoko, H. murihiku and H. relegatus have a bifid (deeply notched) apex. Phylogenetic data currently suggests that Hylaeus originates from Australia, arising around 30 million years ago. One dispersal event would have led to the species found in New Zealand, and another separate dispersal event leading to the worldwide distribution of species found outside Australasia, with both these events having occurred between 22 and 23 million years ago. • Hylaeus (Analastoroides) Rayment, 1950: Hylaeus foveatus (Rayment, 1950) • Hylaeus (Edriohylaeus) Michener, 1965: Hylaeus ofarrelli Michener, 1965 • Hylaeus (Euprosopellus) Michener, 1965: Hylaeus certus (Cockerell, 1921); Hylaeus chrysaspis (Cockerell, 1910); Hylaeus dromedarius (Cockerell, 1910); Hylaeus pergibbosus Cockerell, 1926 • Hylaeus (Euprosopis) Perkins, 1912: Hylaeus disjunctus (Cockerell, 1905); Hylaeus elegans (Smith, 1853); Hylaeus honestus (Smith, 1879); Hylaeus husela (Cockerell, 1910); Hylaeus violaceus (Smith, 1853) • Hylaeus (Euprosopoides) Michener, 1965: Hylaeus amatus (Cockerell, 1909); Hylaeus cyanurus (W. Kirby, 1802); Hylaeus lubbocki (Cockerell, 1905); Hylaeus musgravei Cockerell, 1929; Hylaeus obtusatus (Smith, 1879); Hylaeus perplexus (Smith, 1854); Hylaeus rotundiceps (Smith, 1879); Hylaeus ruficeps (Smith, 1853) • Hylaeus (Gephyrohylaeus) Michener, 1965: Hylaeus sculptus (Cockerell, 1911) • Hylaeus (Gnathoprosopis) Perkins, 1912: Hylaeus albonitens (Cockerell, 1905); Hylaeus amiculiformis (Cockerell, 1909); Hylaeus amiculinus (Cockerell, 1922); Hylaeus amiculus (Smith, 1879); Hylaeus chromaticus (Cockerell, 1912); Hylaeus euxanthus (Cockerell, 1910); Hylaeus theodorei (Perkins, 1912) • Hylaeus (Gnathoprosopoides) Michener, 1965: Hylaeus bituberculatus (Smith, 1879); Hylaeus philoleucus (Cockerell, 1910) • Hylaeus (Heterapoides) Sandhouse, 1943: Hylaeus bacillarius (Cockerell, 1914); Hylaeus delicatus (Cockerell, 1911); Hylaeus digitatus (Houston, 1975); Hylaeus exleyae (Houston, 1975); Hylaeus extensus (Cockerell, 1916); Hylaeus halictiformis (Perkins, 1912); Hylaeus leviceps (Houston, 1975); Hylaeus nigriconcavus (Houston, 1975) • Hylaeus (Hylaeorhiza) Michener, 1965: Hylaeus nubilosus (Smith, 1853) • Hylaeus (Hylaeteron) Michener, 1965: Hylaeus douglasi Michener, 1965; Hylaeus hemirhodus Michener, 1965; Hylaeus murrumbidgeanus Houston, 1981; Hylaeus riekianus Houston, 1981; Hylaeus semirufus (Cockerell, 1914) • Hylaeus (Laccohylaeus) Houston, 1981: Hylaeus cyanophilus (Cockerell, 1910) • Hylaeus (Macrohylaeus) Michener, 1965: Hylaeus alcyoneus (Erichson, 1842) • Hylaeus (Meghylaeus) Cockerell, 1929: Hylaeus fijiensis (Cockerell, 1909) • Hylaeus (Planihylaeus) Houston, 1981: Hylaeus daviesiae Houston, 1981; Hylaeus jacksoniae Houston, 1981; Hylaeus probligenatus Houston, 1981; Hylaeus quadriceps (Smith, 1879); Hylaeus trilobatus (Cockerell, 1910) • Hylaeus (Prosopisteron) Cockerell, 1906: Hylaeus accipitris (Cockerell, 1914); Hylaeus albozebratus Michener, 1965; Hylaeus amatulus (Cockerell, 1922); Hylaeus aralis (Cockerell, 1916); Hylaeus asperithorax (Rayment, 1927); Hylaeus auriferus (Cockerell, 1918); Hylaeus basilautus (Rayment, 1953); Hylaeus baudinensis (Cockerell, 1905); Hylaeus bicoloratus (Smith, 1853); Hylaeus bicuneatus (Cockerell, 1910); Hylaeus bidentatus (Smith, 1853); Hylaeus blanchae Rayment, 1953; Hylaeus brevior (Cockerell, 1918); Hylaeus burnsi (Michener, 1965); Hylaeus chlorosomus (Cockerell, 1913); Hylaeus cliffordiellus Rayment, 1953; Hylaeus crassifemoratus (Cockerell, 1922); Hylaeus cyaneomicans (Cockerell, 1910); Hylaeus distractus (Cockerell, 1914); Hylaeus elongatus (Smith, 1879); Hylaeus eugeniellus (Cockerell, 1910); Hylaeus flavojugatus (Cockerell, 1912); Hylaeus frederici (Cockerell, 1905); Hylaeus greavesi (Rayment, 1935); Hylaeus hobartiellus Cockerell, 1929; Hylaeus infans (Cockerell, 1910); Hylaeus leai (Cockerell, 1912); Hylaeus littleri (Cockerell, 1918); Hylaeus mediovirens (Cockerell, 1913); Hylaeus microphenax (Cockerell, 1910); Hylaeus minusculus (Cockerell, 1913); Hylaeus murrayensis Rayment, 1935; Hylaeus nigrescens (Cockerell, 1918); Hylaeus perhumilis (Cockerell, 1914); Hylaeus perpictus Rayment, 1935; Hylaeus pictulus Michener, 1965; Hylaeus primulipictus (Cockerell, 1905); Hylaeus procurvus (Rayment, 1939); Hylaeus quadratus (Smith, 1853); Hylaeus sanguinipictus (Cockerell, 1914); Hylaeus scintillans (Cockerell, 1922); Hylaeus scintilliformis (Cockerell, 1913); Hylaeus scintillus (Cockerell, 1912); Hylaeus semipersonatus Cockerell, 1929; Hylaeus serotinellus (Cockerell, 1906); Hylaeus simplus Houston, 1993; Hylaeus subcoronatus Rayment, 1935; Hylaeus trimerops (Cockerell, 1916); Hylaeus turgicollaris Michener, 1965; Hylaeus vittatifrons (Cockerell, 1913); Hylaeus wilsoni (Rayment, 1928); Hylaeus woyensis Rayment, 1939; Hylaeus wynyardensis Cockerell, 1929; Hylaeus xanthaspis (Cockerell, 1910); Hylaeus xanthognathus Rayment, 1935; Hylaeus xanthopsyche (Cockerell, 1922) • Hylaeus (Pseudhylaeus) Cockerell, 1929: Hylaeus albocuneatus (Cockerell, 1913); Hylaeus albomaculatus (Smith, 1879); Hylaeus hypoleucus (Cockerell, 1918); Hylaeus mirandus (Rayment, 1930); Hylaeus multigibbosus Michener, 1965; • Hylaeus (Rhodohylaeus) Michener, 1965 • Hylaeus (Sphaerhylaeus) Cockerell, 1929 • Hylaeus (Xenohylaeus) Michener, 1965 Asia China 21 species have been formally identified and described in China. These are as follows: Hylaeus (Dentigera) luna, Hylaeus asiaticus, Hylaeus difformis, Hylaeus dolichocephalus, Hylaeus dorni, Hylaeus fuliginosus, Hylaeus mongolicus, Hylaeus niger, Hylaeus paulus, Hylaeus perforatus, Hylaeus potanini, Hylaeus przewalskyi, Hylaeus sibiricus, Hylaeus sinensis, Hylaeus medialis, Hylaeus pfankuchi, Hylaeus floralis, Hylaeus concinnus, Hylaeus nigricallosus, Hylaeus confusus and Hylaeus variegatus. Japan 23 species of Hylaeus are formally identified in Japan. == Ecology ==

Nesting Biology Hylaeus nests in premade holes and prefers to nest in wood, but will nest in dead stems, rocks, and earthworm burrows. When a suitable premade hole is found, it is then divided by transverse partitions of clear cellophane-like material. The inner most cell is the one farthest from the nest entrance, and is characterised by a round distal end in order to fit the hole. Cell volumes are more or less constant. Lateral burrows are not constructed in this genus, but cells are placed end to end in the main nest. Hylaeus lines their nest with a waterproof and contaminant proof clear cellophane substance that does not melt or dissolve with strong chemicals. They also secrete a substance that protects the nest from fungi and bacteria. This substance is secreted from the mandibles. Food mass placed in cells is liquid, even watery in some cases. It fills the bottom part of the water-proof cells. This liquid state is due a relatively small amount of pollen deposited in it from the crop. Pollen is carried internally in the crop. Pollen-grooming movements by this genus to get pollen to the mouth only take pollen from the head and forelegs, with pollen on other parts of the body being lost. It is thought that the internal method of carrying pollen via the crop is an ancestral trait compared to scopal transport that other bees perform. This makes for an interesting question of whether the species is an effective pollinator as the relative importance of their role as pollinators is unknown. Hylaeus are considered generalist species, foraging on multiple species but have been documented to frequently visit specific plants within their established area. and are considered to be an important contributor to pollination. As this species lacks the external features to collect pollen, they pollinate other flowers when they insert their heads into deep throated flowers to harvest pollen and nectar. This results in excess pollen gathering around their head and thorax on their plumose hairs in which they transport to other flowers. These physical attributes raise concerns regarding their effectiveness as pollinators as they are unable to carry the same amount of pollen as other bee species and have been observed not coming into contact with the stigmas to effectively pollinate flowers, thus resulting in pollen theft. Additionally, the Hylaeus forage within short distances of their burrows ultimately resulting in pollen limitations within their environment. however, when comparing their pollination effectiveness to other pollinator species like the ant, the Hylaeus is not as effective. Multiple literary sources indicate that further studies regarding their pollination effectiveness should be performed for each individual species and their respective global locations to determine if pollination rates change within species and to investigate the effectiveness of the genus as a pollinator. == Conservation ==

Nearly half of the Hylaeus species found in Hawaii are under threat, primarily due to loss and alteration of habitats. An estimated 10 species of Hylaeus may already be extinct in the Hawaiian Islands. In Australia, the presence of commercial honey bees has been found to reduce the fecundity of the endemic Hylaeus alcyoneus, with 23% less nests being made when honey bees were present. ==Selected species==

Species of Hylaeus include: • Hylaeus agilis • Hylaeus alcyoneus - banksia bee • Hylaeus anthracinus – anthricinan yellow-faced bee • Hylaeus assimulans – assimulans yellow-faced bee • Hylaeus facilis – easy yellow-faced bee • Hylaeus globuliferus • Hylaeus hilaris – hilaris yellow-faced bee • Hylaeus krombeini • Hylaeus kuakea • Hylaeus longiceps - longhead yellow-faced bee • Hylaeus mana • Hylaeus nigritus • Hylaeus punctatus • Hylaeus sanguinipictus • Hylaeus sedens • Hylaeus signatus ==See also==