UH entomologists develop important tool to study and conserve wēkiu bug

University of Hawaiʻi at Mānoa
Dan Rubinoff, (808) 956-8432
Professor, Plant and Environmental Protection Sciences
Jesse Eiben, (808) 932-7153
Assistant Professor, College of Ag, Forestry & Natural Resources
Posted: Sep 4, 2014

Wekiu bug feeding on fly's head.
Wekiu bug feeding on fly's head.
Wekiu in the wild.
Wekiu in the wild.

Entomologists from the University of Hawai‘i at Mānoa and Hilo published the article, “Application of Agriculture-Developed Demographic Analysis for the Conservation of the Hawaiian Alpine Wēkiu Bug,” in the prestigious scientific journal Conservation Biology (http://onlinelibrary.wiley.com/enhanced/doi/10.1111/cobi.12315).

Daniel Rubinoff of UH Mānoa’s College of Tropical Agriculture and Human Resources, and Jesse Eiben of UH Hilo’s College of Agriculture, Forestry and Natural Resource Management, describe how they are able to study and help to conserve the rare native insect using methods that were originally developed to track and control agricultural pests.

The wēkiu bug is an endemic insect only found on the summit of Mauna Kea. It has a remarkable ability to survive in the volcano’s harsh, high-elevation alpine desert above the treeline, but it lives nowhere else in the world—except in a few laboratories. The wēkiu bug is important to scientists because it is an indicator of natural resource degradation due to human disturbance. It lives on the summit’s cinder cones, some of which have been altered for telescope facility construction.  Thus, it is important to be able to monitor its status to assess the environmental impact of existing and future construction.

Because it is difficult to find and study the insects in their natural habitat, Drs. Rubinoff and Eiben developed “life tables” to observe them in the lab, discovering at what temperatures the insects grow best, and then finding those temperatures in their native environment. With the predictions created by raising the wēkiu bug in captivity at various temperatures over the course of three years, they have created a predictive model to monitor the growth of the wēkiu bug in its natural habitat.

This method was originally created to study agricultural pests, so farmers would be able to apply insecticides at the optimal time of day and during the correct growth stage on the host plant. Explains Dr. Rubinoff, “Ultimately, by using a model designed to control pest bugs in fields, we have offered a way to help save a special insect restricted to the highest peaks of Hawai‘i’s tallest volcano.”

Many insects that should be considered for conservation are often overlooked because of a lack of data due to the insects’ secretive habits. The detailed information necessary to monitor insect populations and range is often difficult to acquire, especially for rare species in remote areas. The experiments by Drs. Rubinoff and Eiben can be used to help conservation efforts of rare insects by allowing researchers to optimize their field monitoring methods and timing, only searching for species of concern in places and at times that match rare insects’ preferred conditions. That means that, for the wēkiu bug, there are fewer potential impacts on the summit from looking for the insects at the wrong times, and more efficient and cost-effective fieldwork. Most importantly, if there are ever negative impacts to the wēkiu bug populations, researchers and land managers will be able to discover this decline faster and, hopefully, work to help them recover.

More information about this research may be found at the website at http://www.ctahr.hawaii.edu/rubinoffd/rubinoff_lab/projects/wekiu_bug/wekiu%20bug.htm.

For more information, visit: http://www.ctahr.hawaii.edu/site/