Yellow faced bees: Hylaeus melanothrix
(Hymenoptera: [Apoidea:] Colletidae: Hylaeinae)
Profile prepared by Karl Magnacca, USGS-BRD, Kilauea Field Station
Hylaeus melanothrix is a bee endemic to the island of Maui in Hawaii. It is a member of the dumetorum species group, distinguished by the lack of yellow marks except on the face, and the very long body hair. The species is has not been collected in over 100 years, and may be extinct.
Xerces Red List Status: Critically Imperiled
Canada – Species at Risk Act: N/A
Canada – provincial status: N/A
USA – Endangered Species Act: None
USA – state status: None
IUCN Red List: N/A
This species is extremely rare, known from few specimens collected over 100 years ago. However, the rain forests of East Maui are difficult to access and collect in and have not been searched for bees recently. Therefore, it is likely that H. melanothrix persists, though it may still be rare.
Males: Black, face with three separate, irregular yellow marks; otherwise unmarked. Scape strongly arched, almost hooked. Hairs of head and thorax very long.
Females: Black, unmarked. Hairs as in male. Hylaeus melanothrix is a member of the dumetorum species group. It is distinguished by the long hairs and hooked scape from all but H. filicum, which has much more extensive markings in both sexes.
Hylaeus melanothrix was described as Nesoprosopis melanothrix by Perkins (1899). Nesoprosopis was reduced to a subgenus of Hylaeus by Meade-Waldo (1923). The most recent taxonomic treatment was Daly and Magnacca (2003).
Hylaeus melanothrix inhabits montane wet forest and probably nests in wood like related species. Nothing more is known about it.
Hylaeus melanothrix has been collected relatively few times, from the moutains of East Maui.
The rarity of H. melanothrix and lack of knowledge about its requirements make it difficult to assess threats. Habitat degradation due to feral pigs and invasive plants is probably the most serious threat.
The top conservation priority is to document the continued existence of the species. The areas where it is likely to be found are protected under the jurisdiction of the Nature Conservancy, the State of Hawaii, and the National Park Service. It is possible that this species is not even endangered, but simply overlooked. Research is needed in order to locate extant populations and determine reasons for rarity.
Daly, H. V., and K. N. Magnacca. 2003. Insects of Hawaii, Vol. 17: Hawaiian Hylaeus (Nesoprosopis) Bees (Hymenoptera: Apoidea). University of Hawaii Press, Honolulu. 234 pp.
Meade-Waldo, G. 1923. Hymenoptera, fam. Apidae, subfam. Prosopidae, fasc. 181. Pp. 1-45 in P. Wytsman (ed.), Genera Insectorum. L. Desmet-Verteneuil, Brussels.
Perkins, R. C. L. 1899. Hymenoptera, Aculeata. Pp. 1-115 in D. Sharp (ed.), Fauna Hawaiiensis, Vol. 1. Cambridge University Press, Cambridge, United Kingdom.
Bishop Museum Extinct Species – Insects Lists H. melanothrix as extinct. Updated March 21, 2002.
Magnacca, K. N. 2005. Species Profile: Hylaeus melanothrix. In Shepherd, M. D., D. M. Vaughan, and S. H. Black (Eds). Red List of Pollinator Insects of North America. CD-ROM Version 1 (May 2005). Portland, OR: The Xerces Society for Invertebrate Conservation.