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The Honolulu Advertiser

Posted on: Monday, February 7, 2005

Experts strive to save native aquatic insects

By Timothy Hurley
Advertiser Staff Writer

There are few things as gratifying for Ronald Englund as when a Hawaiian damselfly whizzes by. That's when he knows everything's right with the world.

Ronald Englund, an aquatic insect expert with the Bishop Museum, looks for native species at Lili'uokalani Botanical Garden in Liliha.

Rebecca Breyer • The Honolulu Advertiser

Englund, an aquatic insect expert with the Bishop Museum, said the damselfly, by its mere presence, indicates that a freshwater ecosystem is healthy and pristine, both free-flowing and free of alien species.

"It's really something to be happy for," Englund said. "If you see the damselfly, you know this is the way it ought to be. This is the way it was even before humans arrived in Hawai'i."

Unfortunately, due to a variety of factors, there are fewer and fewer places in the Islands where the damselfly takes flight. On O'ahu, it requires a dangerous hike into the uplands before you can see them. There aren't many accessible areas on the Neighbor Islands, either.

That's not good for the 400 to 500 other known native aquatic species that live in Hawai'i's freshwater ponds, wetlands and streams.

"They're all in the same boat," Englund said.

Insects like the giant Hawaiian dragonfly, pictured here, are a key component of biodiversity in freshwater ecosystems, yet are threatened by more than 70 introduced fish species.

Rebecca Breyer • The Honolulu Advertiser

But while most conservationists here are busy trying to save mammals, birds and plants, Hawai'i's beleaguered aquatic insects go largely unnoticed. Englund would like that to change.

These bugs, he said, are a key component of biodiversity in various freshwater ecosystems, yet they are threatened by more than 70 introduced fish species that have unleashed devastating effects.

Why isn't more effort being put into aquatic insect conservation?

"They aren't warm and fuzzy. They aren't cute. They aren't like the (Hawaiian) monk seal or the birds," Englund said.

They're also perceived as pests, lumped in the same lowly category with cockroaches, mosquitoes and centipedes. But aquatic insect predators in the odonata order, which includes damselflies and dragonflies, provide a service by eating mosquitoes.

'Incredibly beautiful'

Englund, who has studied aquatic bugs across the Pacific, said these insects hold a special place in Hawaiian culture and other Polynesian traditions. For example, at the top of Kaua'i's Mount Wai'ale'ale, near a bog where dragonflies are numerous, there's a heiau with a name that incorporates the Hawaiian word for dragonfly: pinao.

"In the Marquesas, if a damselfly flies into your house, it's a good omen," he said.

There's another good reason to save Hawai'i's damsels in distress, according to Englund: "They are incredibly beautiful, as far as the insect world. They come in different shapes and colors, from a bright frosty blue to brilliant oranges, reds and yellows."

The Hawaiian damselflies are some of the largest in the United States. While other native aquatic insects evolved from the saltwater ocean environment, the damselfly colonized the Islands by flying here. And like lions and tigers in their respective habitats, damselflies and dragonflies are the reigning species in their water-bug world.

In Hawai'i, the damselfly, like so many other creatures, evolved into different species that became established on an array of islands, each carving out their own separate habitat in the aquatic landscape. Some live in the face of a waterfall, others live in the white water. Some types live in the calm waters, while others are nearer to the ocean.

Some damselflies have even evolved into terrestrial insects, living in ferns in the rain forest — a phenomenon found only in Hawai'i and Fiji.

There are other fascinating Hawaiian aquatic insects as well. There's a type of nabid that is a terrestrial bug everywhere else in the world except Hawai'i. Here, it evolved to prey on aquatic insects in their realm.

Then there are the water skaters, 60 or 70 different species of a bright metallic green aquatic fly that performs a Michelle Kwan-like dance on the surface of still-water habitats.

There are also aquatic moths, some of which can live underwater for up to two weeks.

Species disappeared

Hawai'i's aquatic insects apparently began their decline after tilapia and other fish species were introduced to freshwater bodies for mosquito control in the late 19th century. Stream diversions and channeling also played havoc with native insects, as did habitat loss and increasing water-quality problems.

One way scientists know native insect populations are waning is by going to the Bishop Museum collections, which date to the 1890s, and finding examples of bugs and the locations they were collected. Many species can't be found at the same places anymore.

One species, the orangeblack Hawaiian damselfly, used to be the most common garden insect in Honolulu in the late 19th century, according to one entomologist at the time. Today, the species is confined to about 100 yards of a remote stream high on military-controlled land.

Englund said a recent attempt to move some of the orangeblack Hawaiian damselflies to another stream was foiled after someone put crayfish in the stream.

Despite the setbacks, Englund said, there is room for optimism. The Salvinia molesta problem at Lake Wilson brought new attention to the health of freshwater ecosystems. Awareness of freshwater-related threats to humans also was heightened by a dengue fever outbreak and potential for West Nile virus, both of which are mosquito-borne diseases.

Gov. Linda Lingle last month authorized money to expand the development of an aquatic invasive species response team, a proposal that grew out of last year's creation of a state aquatic invasive species management plan.

Englund is proposing that the state restore at least one stream on each island to create a decent habitat for native aquatic insects. The effort would require the complete eradication of invasive fish from a stream and then the relocation of natives into the restored habitats. Isolated anchialine ponds and steep streams entering the coast as waterfalls are best-suited, he says.

Restoration of a small stream might cost $50,000, a relatively small price to pay in the overall conservation scheme, he said, but more research is needed.

"If the bugs can be worked out, it can be done," he said.

University of Hawai'i entomology professor Dan Rubinoff, who has been studying the native Hyposmocoma aquatic moths and their rapid evolution in Hawai'i, agrees conservation is needed to preserve native aquatic insects.

"It's one of the last chances to save a vestige of what used to be here," Rubinoff said. "It's shocking the number of people who don't know what Hawai'i used to look like."

Reach Timothy Hurley at thurley@honoluluadvertiser.com or (808) 244-4880.