Yellow faced bees: Hylaeus solaris

(Hymenoptera: [Apoidea:] Colletidae: Hylaeinae)

Profile prepared by Karl Magnacca, USGS-BRD, Kilauea Field Station

Hylaeus solaris is a coastal bee endemic to the island of Kauai in Hawaii. It is distinguished by the single large facial mark, covering most of the face, and the distinctive scape of the male. It is restricted to a few small, widely scattered sites, and populations are vulnerable to extirpation.

red list profile

conservation status

Xerces Red List Status: Critically Imperiled
Other Rankings:

Canada – Species at Risk Act: N/A
Canada – provincial status: N/A
Mexico: N/A
USA – Endangered Species Act: None
USA – state status: None
NatureServe: GNR
IUCN Red List: N/A

This species is restricted to geographically small, potentially vulnerable populations.

description and taxonomic status

Males: Face marks yellow, completely filling in the area below the antennae and extending dorsally along the eye in a broad stripe. Scape moderately dilated, widest around the middle, sometimes with a mark. Hair at abdominal apex short, golden, prostrate; hair of scutum extremely short.

Females: Entirely black, lacking coloration; hair as in male.

Hylaeus solaris is not closely related to other Hawaiian species. It is unmistakable among Kauai species; the only species with which it might be confused is the possibly-extinct H. finitimus, which has a narrow scape in the male.

Hylaeus solaris was first collected in 1989 and described in Daly and Magnacca (2003).

life history

Hylaeus solaris is only found in coastal strand. Nesting habits are unknown, but it probably nests in the ground.


Hylaeus solaris has been recently collected only from Polihale and Keoneloa Bay. Additional sites may exist on Kauai, but it is likely that they will be small areas. Like H. flavifrons, it may also be found on Niihau and Lehua.


The biggest threat to H. solaris is habitat loss. Although the species can be found in relative abundance at Polihale, native coastal strand vegetation is now extremely rare. Coastal habitat has been heavily impacted by development and invasive plants. Remaining habitat on Kauai is threatened by visitor impacts and development.

conservation needs

The coastal site at Polihale and Barking Sands is protected by the State of Hawaii and the U.S. Air Force, but faces continued impacts from visitors and military activities. Other sites are not protected and may be destroyed by development. Research is needed to find additional populations on Kauai.


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.


Magnacca, K. N. 2005. Species Profile: Hylaeus solaris. 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.