Range, habitat, and ecology of the wekiu bug (Nysius Wekiuicola), a rare insect species unique to Mauna Kea, Hawaii Island, Final report

Author:

Englund, R. A., Polhemus, Dan A., Howarth, Francis G., Montgomery, S.L.

Title:

Range, habitat, and ecology of the wekiu bug (Nysius Wekiuicola), a rare insect species unique to Mauna Kea, Hawaii Island, Final report

Year:

2002

Subject:

Wekiu bug Nysius wekiuicola

Summary:

The Hawaii Biological Survey of the Bishop Museum was contracted by the Office of Mauna Kea Management (OMKM) to assess the distribution and habitat use of the wekiu bug (Nysius wekiuicola Ashlock and Gagne), which is endemic to Mauna Kea. This project arose after a preliminary study conducted by the Smithsonian Institution (Polhemus 2001) found relatively high numbers of wekiu bugs on Puu Hau Kea in June 2001 (Appendix 1), in contrast to other similar studies that had indicated population declines. Because of these findings, OMKM was interested in obtaining further information regarding the distribution and status of wekiu bugs in the alpine zone of Mauna Kea. The three major objectives of this study were to 1) survey for the presence or absence of wekiu bugs at the summits of various puu’s (cinder cones) located in the alpine zone of Mauna Kea, 2) determine the elevational distribution of wekiu bugs on Mauna Kea, and 3) assess whether different pitfall trapping methods used in earlier Bishop Museum studies provide comparable data in regard to wekiu bug capture rates. Wekiu bug surveys for this study occurred in April and May 2002, with additional sampling on Puu Hau Kea in September 2002. Sampling in the alpine zone of Mauna Kea in April/May 2002 was coordinated with Pacific Analytics (Pacific Analytics 2002) wekiu bug monitoring in the summit area. Our study used identical collecting techniques for the shrimp pitfall traps, and was conducted in nearly the same time frame. Previous Bishop Museum wekiu bug studies were concentrated directly around the astronomical observatories (Gagne and Howarth 1982, Howarth and Stone 1982). Howarth et al. (1999) also examined areas in the Mauna Kea Science Reserve. Because it is such a vast area, little previous information was available regarding the overall elevational range and distribution of the wekiu bug throughout the entire alpine zone of Mauna Kea. The current study assessed the presence or absence of wekiu bugs throughout the alpine zone, and provided valuable new information that will assist in conserving and managing this rare species. Areas surveyed during this study included Puu Makanaka, Puu Mahoe, Puu Ala, Puu Poepoe, Puu Keonehehee and adjacent unnamed cones, and several unnamed cones near the VLBA (Very Long Baseline Array) facility. To assess the effectiveness of various trapping methods on wekiu bug capture rates, Puu Hau Kea was sampled in both July 2001 by Polhemus (2001) and again by our team in September 2002.

URL:

http://hbs.bishopmuseum.org/pdf/wekiufinal-low.pdf

Collection:

Monographs