Hylaeus in Hawaii
Hylaeus in Hawaii |
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Hylaeus flavipesIslands: Lanai, Maui, HawaiiLocations: Lanai - (Kahue) Hawaii - (Hale Pohaku, Kaalualu, Ka Lae, Kalu, Kaohe, Kau, Kaulana, Kipuka Nene, Mauna Kea SP, PTA, Puu Pa, Redleg Trail, South Point) Habitats: Coast, and lowland and montane dry shrubland and forest Plants: Dodonaea, Jacquemontia, Myoporum, Scaevola, Sesbania, Sida, Sophora, Styphelia, Tournefortia, Tribulus Xerces: No info. Insects of Hawaii: Small to medium-sized bees with very short to short malar spaces and clear to slightly smoky wings. Male lower face entirely yellow, extended at sides in a broad stripe above antennal sockets, scape black or with an apical yellow spot or a yellow stripe extended the full length ofthe scape; tibiae and tarsi of all legs yellow with some subapical brown or orange spots on the tibiae visible in caudal view. Female black and usually unmarked (rare specimens may have small yellow marks in paraocular areas). Hylaeus flavipes from Hawaii and H. blackburni from Maui and Lanai are treated here as one species under the senior name, H. flavipes. Male bees referred to these two species are similar in the extensive yellow marking of the face, yellow tibiae and tarsi of all legs, sculpture of the propodeum, and genitalia. In the past the males have been distinguished primarily by the color of the scape and mandible: black and unmarked in H. HAWAIIAN HYLAEUS 93 flavipes, marked with yellow in H. blackburni. Recent collections reveal variation in the degree of melanism of male bees that largely invalidates this distinction. On Hawaii (South Point) the darkest males have the scape, mandible, and pronotal collar black; no yellow mark on the pronotal lobes; and the hind tibia marked with a small brown spot in front and a larger dark brown spot behind. The least melanic males have the scape with an apical yellow stripe extended up to half the length of the scape; yellowish areas on the mandible; yellow marks on the pronotal collar and lobe; and the hind tibia with a reddish spot in front and a smaller brown spot behind. Strict use of Perkins key (1910:602) would identify both H. flavipes and H. blackburni from this one population. On Lanai and Maui, males are less melanic than those on Hawaii. Here males have a yellow stripe extended the entire length of the scape, the mandible partly or mostly yellow, pronotal lobes yellow, pronotal collar with or without a yellow spot, and hind tibia with an orange spot in front and an orange spot or brown spot behind; they are also usually smaller. Although some differentiation in color patterns exists between the populations on Hawaii and those on Maui and Lanai, we chose to treat the differences as geographic variation within one species. Confusion has surrounded the taxonomy of these species. Hylaeus flavipes was described by Smith (1853) from one male labeled Sandw. I. Beechey and was stated to have a black scape. The male holotype is in The Natural History Museum, London, and matches the description. The collection was presumed to be from Oahu because the ships naturalist was said to have prevented by illness from pursuing his research among the islands (see Introduction), yet we have seen no other specimens taken on Oahu. At least one other species collected by the Beechey expedition, Odynerus obscurepunctatus, was collected by Perkins only on Hawaii (Perkins 1899:60). Perkins (1899:99) assumed H. flavipes was from Oahu and did not mention other specimens from Oahu or elsewhere. Later, he recorded H. flavipes from the island of Hawaii and regarded the species as distinct from H. blackburni (1910:605). Fullaway (1918:396-397) offered a contrary opinion, stating without explanation Flavipes=blackburni. He also recorded collections from Hawaii and described the male as often having a yellow spot on the scape. Although the type locality remains in question, the name H. flavipes has been associated with males from the island of Hawaii that have reduced or no yellow marking on the scape. Hylaeus blackburni was described by Smith (1879a) from one male and one female labeled Maui.” The male was stated to have the scape with a yellow line in front. The male lectotype is in London and matches the description. However, the type was somehow mislabeled as Prosopis simillima, an error corrected by Houston (1981:27). Blackburn (1886:141-142) supplemented the description of H. blackburni and described considerable variation. Perkins (1899:97) identified bees in his own collection from Maui as H. blackburni and redescribed both sexes, stating that the male had the front half of the scape yellow. He commented that Blackburn must have had more than one species when he wrote about variation in H. blackburni. Both H. flavipes and H. ombrias are typically coastal or lowland species that have established disjunct populations above 5000 ft in the Pohakuloa area of Hawaii. They may have formerly been continuous with populations on the Kona coast that are now extirpated. Individuals of both species from montane areas often have longer vertex and scutum hairs than those from the lowlands. Males of H. flavipes from upland areas may have the paraocular marks in a narrowing stripe as in H. niloticus rather than the typical broad stripe, but can easily be distinguished from that species by the extensive leg markings as well as the dilated process of S8. Insects of Hawaii Volume 17 
UH/DOD: This species was previously known from several widely scattered localities on Hawaii: Kipuka Nene and South Point in Kau, and Kaohe GMA and Hale Pohaku on Mauna Kea. In this survey, H. flavipes was found at all of these except the last, and in addition was found in Pohakuloa Training Area at Area 21 and Area 4, and nearby at Mauna Kea State Park (Figure 6). At all the Mauna Kea/PTA sites, it was associated with Myoporum. Previously, it was collected at Sophora at Kipuka Nene and Hale Pohaku (Daly and Magnacca 2003), but Sophora flowering during the survey period at these areas was brief and occurred in the fall. At Pohakuloa, H. flavipes was found only at a few sites, and in July but not August. However, to the west at Kaohe on Mauna Kea they were absent in July after having been found there in May, indicating that they may only be active for short periods but that their seasons differ at different sites. Hylaeus near military lands
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