Hylaeus in Hawaii


Hylaeus mimicus

Islands: Oahu

Locations: Oahu - (Aiea Trail, Lanihuli, Wiliwilinui Trail)

Habitats: Montane mesic and wet forest

Plants: Acacia, Ilex, Metrosideros, Psychotria, Scaevola

Xerces: No info.

Insects of Hawaii: Small bees with slightly smoky wings. Male face with three marks separated by dark margins of cIypeus, extended narrowly along eye; scape strongly arched, almost angled, with a groove underneath. Female with long, broad paraocular marks; a triangular cIypeal mark; and marks on pronotal collar, lobes, and tegulae. See remarks for similar species.

This species may be responsible for purported records of H. filicum from Oahu, as it is very similar. It can be distinguished by the much shorter hair on the mesonotum and vertex (that of H. filicum measures 12-20). It also lacks the unusual bulge at the apex of the scape that causes that of H. filicum to be much more strongly arched on the lower surface than the upper. The upper frons of H. mimicus appears dark due to close sculpture, but it lacks the conspicuous rhomboid patch of dark hairs found in H. filicum and other related species. The amount of yellow on the face of the female is unusual, and similar to that of H. kokeensis, which has a yellow median plate in both sexes. It is widely present on leeward ridges of the Koolau Mountains, but appears to be less abundant than H. connectens and H. unicus, the two species most commonly collected there.
Insects of Hawaii Volume 17PDF

UH/DOD: This is an Oahu endemic that appears to be confined to the Koolau range. In 1999-2002 it was collected from Aiea and Wiliwilinui ridges on multiple occasions and from a variety of flowers (Daly and Magnacca 2003). During this survey, only two individuals were found, one each on Poamoho and Lanihuli ridges (Figure 9). One of the plants it was collected on previously, Scaevola gaudichaudiana, was flowering abundantly through most of the year but had few visitors; however, there was almost no flowering of Acacia koa, another tree that several H. mimicus were collected from previously. While not a commonly-used flower in general by Hylaeus, if H. mimicus is linked to koa then it may explain the reduction in numbers of this species.
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