Distribution and Seasonal Occurrence of Forcipomyia taiwana (Diptera: Ceratopogonidae) in the Nantou Area in Taiwan

We studied the distribution of Forcipomyia taiwana (Shiraki) in Taiwan, and found this species almost island-wide. Midge seasonality was studied for 4 yr at 3 sites in Nantou, central Taiwan, to identify the extent and causes of midge population outbreaks. The midge population in 1995 was significantly lower than in 3 other years because several typhoons inundated breeding sites. Maximum populations of F. taiwana occurred in June, July, and August. There was a highly significant correlation between the monthly abundance of F. taiwana and temperature and rainfall. A step-up multiple regression indicated that temperature was the most important factor leading to the outbreaks of F. taiwana. Temperature increases from 15 degrees C to near 30 degrees C will increase the midge abundance.