Native Hawaiian damselflies are a remarkable cluster of 25 species diversified from a single waif arriving in Hawai‘i long ago to occupy many aquatic niches and rain holding lily and ‘ie’ie leaves. The Blackline Damselfly or Rainbow-Eye Damselfly, Pinao Ānuenue, (Megalagrion nigrohamatum nigrolineatum), ranges on O‘ahu from sea level to 2,400 feet. Most remarkable are their luminous, compound eyes in colors from lime to turquoise to red, this rainbow-eye damselfly is visually striking but very hard to notice. These large, wrap-around eyes give panoramic vision to easily detect and catch flying prey. The brown, 2-inch-long damselfly nymphs (babies) favor a concealed existence clinging under stones or hiding in algae masses, both in moving and quiet waters, for long intervals.
Since the recent discovery of a small, relict, lowland population of Pinao Ānuenue on an undeveloped portion of Hawaiian Memorial Park’s (HMP) property, the small population is being monitored and protected by several activities supported by HMP to help them remain safe. The native damselflies observed on HMP’s property are seen only along a slow moving seep of water that includes an abandoned well, likely dug before 1930 during the area’s use as a dairy farm. The area of HMP’s property where the native damselfly are observed is outside the portion of the property where cemetery expansion improvements would occur. This area would be preserved, and a management plan has been developed to support its continued presence.
The nymphs’ diet includes bloodworms (young midges), larvae of shore flies, sowbugs, and mites. Kalo is one of the few emergent water plants available as perch sites. One major threat is predation on naiads by alien fishes, especially the Western Mosquitofish and Guppy.
Best management practices that would be followed to ensure the safety of the native damselfly and preserve its habitat are listed below:
NOT releasing aquarium fish, Jackson’s chameleons, or chickens which eat nymphs or adults.
NOT uprooting nearby plants or moving stones along the seep that provide shade or hold soil.
NOT removing kalo along the seep, which provide safe perches for emerging young.
NOT planting vegetation at the water’s edge where an emerging young native damselfly may climb for molting to adults and be vulnerable to predatory ants.
NOT placing trash on the ground that can cover or divert water.
DO NOT ACCESS – No Trespassing – Hawaiian Memorial Park (“HMP”) is Private Property and has “No Trespassing signs posted along with motion detection cameras. No one is permitted on HMP land without written permission from Hawaiian Memorial Park Management.
Mahalo for your kōkua.