Hylaeus in Hawaii


Hylaeus mana

Islands: Oahu

Locations: Oahu - (Aiea, Manana Trail, Mauumai, Tripler)

Habitats: Mesic forest

Plants: Psychotria, Santalum, Scaevola

Xerces: Hylaeus mana is a small bee endemic to the island of Oahu in Hawaii. It is distinguished by the extremely small size and narrow process of the 8th sternum of the male, and extensive facial marks of the female. It is known only from four specimens collected in 2002.
Species ProfilePDF

Insects of Hawaii: Very small bees with clear wings. Male face nearly all yellow, only supraclypeal area and narrow margins of clypeus black, the yellow marks extended above antennal sockets; scape weakly dilated, about twice as long as wide, weakly arched. Median process of S8 swollen at base, the remainder weakly dilated and strongly arched. Female with long, broad paraocular marks, a transverse clypeal mark, and marks on pronotal collar, lobes, and tegulae. Both sexes with extensive yellow marks on legs.

This is the smallest species of Hawaiian Hylaeus. The only collection came from a habitat (mesic koa forest) and plant (Santalum) where few bees have been found on Oahu. The weakly arched scape with a poorly developed groove suggests that it may be related to H. dumetorum of Hawaii. Males can immediately be distinguished from the sympatric H. mimicus and H. specularis by the shape of S8, which is hardly dilated and strongly arched; all three males of H. mana have similar facial marks with more yellow than either of those species. Females can be distinguished by the evenly, more widely spaced pits of the frons, and the transverse rather than longitudinal clypeal mark (H. specularis may occasionally have a transverse clypeal mark as well).
Insects of Hawaii Volume 17PDF

UH/DOD: Another rare and recently-discovered Oahu endemic, this species had been known only from 4 specimens collected in 2002 on the Manana Trail at flowers of Santalum freycinetianum. During this survey, it was found at four ridges across the central and eastern Koolau range (Figure 9). All were from the middle or lower portions of the ridge, and of the five collections three were from Santalum (one was of a resting bee on a cool day in the vicinity of flowering Santalum, and the last on Psychotria; the latter is probably an incidental record, since Hylaeus visit Psychotria relatively infrequently). Taken together, these records suggest that H. mana is a specialist on Santalum and is probably restricted to the relatively narrow zone where it occurs in the Koolau range. While Santalum occurs in moderate abundance and H. mana is probably more common than previously recognized, the narrowness of its habitat and the presence of abundant Lasioglossum impavidum around Santalum at some of the sites show that it remains under threat.
Hylaeus near military landsPDF

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Images and information mostly from various works by Karl Magnacca.
Questions? e-mail fstarr@hawaii.rr.com
Starr Environmental