Waipio Valley Stream Restoration Study

Insects: Introduced Species

Scientific name: Ischnura posita
Common name(s): Fragile forktail

Ischnura posita

Status: Introduced

Habitat: Ponds, wetlands, slow-water area of streams

Preferred Area of Stream: Larvae found in thick vegetation on the sides of pools and in wetland habitats and kalo lo‘i

Range in Hawai‘i: Extremely Common on all Hawaiian Islands

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

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

Fact: Fragile forktails are the smallest damselfly species found in Hawai‘i and are easily distinguished by the bright yellow coloration and their being less than half the size of the native Blackburn ’s Hawaiian damselfly. Unlike native damselflies, they are able to withstand predation from introduced fish. They are common in ponds and wetlands, and are even found at high elevation areas such as the Alaka‘i swamp area on Kauai at over 4000 ft (1220 m).