COURTESY BISHOP MUSEUM'S HAWAII BIOLOGICAL SURVEY
A male Megalagrion orobates, or yellowface Kauai damselfly, above, perches on a branch. A UH researcher is looking at the cellular structure of the insect's eyes to learn how it sees so well.
Getting the fly's-eye view
A UH researcher hopes to gain insights into how the damselfly spots prey despite its limits
IN the latest military effort to learn from Mother Nature, a University of Hawaii zoologist has received a $220,000 grant from the Army to look into the vision of the Hawaiian damselfly, a rare winged insect that can spot prey and sex partners against complex, colorful backgrounds.
The money was a windfall for UH researcher Marguerite Butler, a Mililani High School graduate who returned to the islands last fall after a 20-year absence.
"We're trying to find out how they see so well," says Butler, formerly with the University of Tennessee. "They have small eyes and can't focus" -- yet can see prey, rivals and potential mates, moving or still, in both bright and dark surroundings, often amid tropical foliage.
They also have less efficient retinas than mammals and little distance between their eyes, which is a factor in depth perception. All that should make it more difficult for them to gauge distance and size in three dimensions, Butler says, but they excel at those tasks.
The two-year grant came from the Army Research Office, part of the North Carolina-based Army Research Laboratory, which supports a wide range of scientific inquiries, including work on sensors that "improve the Army's ability to detect, identify and engage targets, especially those that are difficult to detect, through the integration of electro-optical components," according to its Web site.
Collaborating with David Preston of the Bishop Museum, Butler said she will use the money to hire some postdoctoral students and perform videotaped experiments in which Hawaii's Megalagrion damselflies go after a meal and also respond to artificial stimuli.
Butler is looking at the cellular structure of damselfly eyes as it relates to function and whether the shifts in habitat and body coloration have occurred simultaneously with eyesight evolution.
Damselflies, related to dragonflies, were once fairly common in many of Hawaii's streams but are now hard to find.
Behind Tripler Army Medical Center, a population of orange-black damselflies, Megalagrion xanthomelas, is kept alive by Army orders to keep a garden hose running around the clock, Preston said.
The water from the hose creates a small artificial stream that empties into the back of Moanalua Gardens.
Preston said he will try to move part of that population to a natural stream, preferably free of guppies, crayfish and other fish that feed on the flies in the egg, larval and adult stages.
"What we want to do is stabilize the population in a location free of predators," he said.
Damselflies come in a wide variety of colors if they are male and are blandly colored as females, Butler said. The spectacular diversity of the Megalagrion genus, found only in Hawaii, might have been achieved in only 5 million years of evolution, she said.
"These different species have adapted to so many kinds of environments," she added. "Some are in bright light, some are in dark, some are in high-elevation bogs. They also breed in waterfalls."