The federal government designated almost 9,000 acres on five islands last month as critical habitat for protected Hawaiian picture-wing fly species known for their elaborate mating performances.

The federal government classified 11 Hawaii picture-wing fly species as endangered and one as threatened in 2006. The Endangered Species Act requires the Fish and Wildlife Service to designate critical habitat areas for these species to assist their protection.

Picture-wing flies, about two to three times the size of common houseflies, are named for the intricate markings on their clear wings.

Researchers have found antibiotic-resistant bacteria on some of the protected species, which could help scientists find new ways to combat diseases such as bird flu and cancer.

Their critical habitat areas cover 32 spots on Oahu, the Big Island, Maui, Molokai and Kauai.

In some areas, invasive feral pigs dig up soil and eat the native plants the flies need to live. Yellow jacket wasps, another invasive species, prey on the picture-wing flies as well as compete with them for food.