Species Diversity within a Community of the Curcurbit Fruit Flies Bactrocera cucurbitae, Dacus ciliatus, and Dacus demmerezi Roosting in Corn Borders Near Cucurbit Production Areas of Reunion Island

In order to better control fruit flies (Diptera: Tephritidae) attacking Cucurbitaceae on Reunion Island (21°6 S/ 55°36 E), biological characteristics (seasonal fluctuation, relative abundance, sex ratio) of communities roosting in corn borders were investigated. The study was conducted in austral summer across a range of altitudes (750–1150 m) corresponding to the main areas of cucurbit cropping. Living adults were recorded roosting on corn planted within or around cucurbit fields. Results showed a high variability in seasonal fluctuation of populations according to local conditions. Bactrocera Cucurbitae (Coquillett) (Diptera: Tephritidae) was the least abundant species (27%) compared to Dacus ciliatus Loew (36%) and Dacus demmerezi Bezzi (37%). Relative abundance of B. Cucurbitae was lowest (< 18%) in high altitude sites (above 1000 m), where D. demmerezi was the most prevalent species (> 56%). Dacus ciliatus showed variable relative abundance (from 18 to 51%) depending on the experimental design (varying in location and in year). Sex ratio was also very variable from one species to another and from one experimental design to another.