Waipio Valley Stream Restoration Study

Insects: Native Species

Scientific name: Megalagrion blackburni
Common name(s): Blackburn’s Hawaiian Damselfly

Megalagrion blackburni

Megalagrion blackburni

Status: Endemic

Habitat: The aquatic larvae are found among large stream rocks and boulders, while the adults are strong flyers and patrol along stream corridors and wetland areas and also range into upland forests.

Preferred Area of Stream: Swift areas of the stream such as riffles and cascades

Range in Hawai‘i: Maui , Moloka‘i, Lana‘i, and Hawai‘i Islands

Diet: A wide range of aquatic insects, small aquatic snails, small aquatic crustaceans such as amphipods, mosquitoes and moths

Predators: Native and introduced fish, dragonflies, introduced crayfish, birds

Fact: Blackburn’s Hawaiian damselfly is the largest damselfly in Hawai‘i and is now relatively uncommon in the Waipi‘o Valley watershed because introduced fish and crayfish prey upon this species. Floods and high stream flows appear to benefit this species because the Blackburn’s Hawaiian damselfly was never observed in upper Lālākea Stream (that flows into Hi‘ilawe Stream and Waipi‘o Valley) until after the massive flooding of March 2004 flushed out many of the introduced fish that allowed for the recovery of this damselfly.