L.A. fly species prefers flowers to fruit

Drosophila gentica. PHOTO: Dr. David Grimaldi, American Natural History Museum

If a fruit fly infestation is leaving you stumped, consider the possibility of it being Drosophila gentica, a species that was previously considered to be present only in Central America.

A study done by a research team from New York’s American Museum of Natural History (AMNH) notes that D. gentica was found earlier this year in Los Angeles. The flies were not an isolated population, either — the study, which appears in the April 29 issue of the online journal PLOS ONE, reports that D. gentica “was the second-most common fruit fly found in the Los Angeles BioSCAN traps. This species was described in 1962 based on specimens collected in El Salvador in 1954, the first and last time it was recorded anywhere until now.” (For the record, the most common species collected in the Los Angeles survey is what you might suspect: D. melanogaster.)

Of particular note is that this species of Drosophila, a genus that is commonly grouped as “fruit flies” or “vinegar flies,” seems to be attracted to neither ingredient. Rather, it prefers to breed on flowers. That’s according to the study’s lead author, Dr. David Grimaldi, curator, Division of Invertebrate Zoology and Professor, Gilder Graduate School for the AMNH. He’s also an adjunct professor of ecology and evolutionary biology at Columbia University, CUNY; and of entomology at Cornell University.

This unusual behavior is why the researchers theorize they’ve skipped over D. gentica’s presence before — previous collection studies always trapped specimens with fruit or other baits. In fact, the flower-baiting trap study also yielded another fly species previously not found in the Western hemisphere: D. flavohirta, which the team theorizes left its native Australia for the Golden State on transplanted eucalyptus trees and shrubs, as it has done previously in South Africa and Madagascar.

So at your next difficult small-fly account, perhaps ignore the bowl of bananas in the kitchen and focus instead on the night-blooming jasmine and eucalyptus arrangement in the dining room.