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There was a time more than a century ago when the orangeblack Hawaiian damselfly was commonly seen whizzing about taro patches and freshwater habitats across the islands.
Today only one population of the colorful native aquatic insect remains on Oahu.
That may be about to change as state scientists have renewed a campaign to establish a second population in an effort to hold off the threat of
extinction for the damselfly, a smaller and more delicate relative of the
dragonfly.
A small pond at the University of
Hawaii’s Lyon Arboretum is the new second home of the native damselfly, or pinao ula, one of six Hawaii damselfly species listed as endangered.
“It looks promising,” said William Haines, research entomologist with
the state Department of Land and Natural Resources’ Hawaii Invertebrate Program.
The pond will be monitored over the next six months to a year to determine whether the effort takes hold, he said.
The orangeblack Hawaiian damselfly was once described in the early 1900s by renowned Hawaii naturalist RCL Perkins as one of the most commonly observed insects on Oahu, seen in gardens and low-lying areas all over the island.
Scientists say the damselflies play a key role in Hawaiian ecosystems, providing food for native birds, as pollinators of native plants and as recyclers of nutrients. Additionally, they help control mosquitoes, midges and other pest insects.
But the species began to disappear in the decades following the 1905 introduction of the mosquitofish in
Hawaii.
By 1979 the insect was missing,
believed to be extinct on Oahu. That was the case until a remnant population was discovered near Tripler Army Medical Center in 1994.
The damselfly was finally added to the U.S. Endangered Species List in 2016.
Meanwhile there have been five
attempts to establish a second population over the years, Haines said. None were successful.
And despite a failed attempt to establish a population in a stream in the Waianae Kai Forest Reserve just late last year, Haines said this time he thinks it might work.
The effort began with the collection of eggs from the Tripler population, which were taken to the state’s captive rearing facility in Kailua, where they were hatched into aquatic larvae called naiads.
The naiads were individually raised for two months and taken to be released into the wild in their aquatic form, just prior to the point where they grow their wings.
Some 300 naiads were released
into the arboretum pond after it was drained and refilled with water free
of any predatory fish.
The work is being conducted in partnership with the University of
Hawaii, the U.S. Fish and Wildlife Service and the Army’s Natural Resources Program on Oahu.
Haines returns to the pond weekly to capture and translocate any predatory dragonflies. He also counts the shed skins of naiads that have grown into adults and surveys for damselflies returning to the pond to defend their territory or mate and lay eggs.
“We hope after they emerge as adults they stay around the release site and lay eggs to hopefully establish a population,” he said.
So far so good. Adult damselflies have been consistently spotted at the pond, and there is clear evidence of mating and laying of eggs.
“What is incredibly positive about this relocation is that we are seeing fit damselflies feeding, establishing territories, mating and laying eggs. I think this gives us a lot of valuable information to move forward with when we conduct releases at other sites in the near future,” state Entomologist Cynthia King said in a news
release.
Haines said the Waianae attempt failed due to an unusually cold winter that produced flash flooding and cold water temperatures. He said the program likely will give the higher-elevation, fish-free stream another go — along with other habitats, both natural and artificial.
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