Species diversity and abundance of Dacus (Diptera: Tephritidae) in five ecosystems of Penang, West Malaysia.
Dacus dorsalis Hend. infested 11, D. cucurbitae Coq. 5 and D. umbrosus F. 2 of the 18 common fruits and vegetables grown in Penang, West Malaysia. D. tau (Wlk.) infested bacang (Mangifera foetida), D. caudatus F. chilli (Capsicum annuum) and D. frauenfeldi Schin. water guava (Eugenia javanica), together with D. dorsalis. Pummelo was found infested for the first time by D. cucurbitae. No flies were trapped using Capilure or another formulation of trimedlure as baits. Cue-lure attracted D. caudatus, D. cucurbitae, D. frauenfeldi, D. occipitalis (Bez.) and D. tau. Methyl eugenol attracted D. caudatus and D. umbrosus. Dorsalure was less attractive to D. caudatus and D. dorsalis than its components, cue-lure and methyl eugenol, respectively, but it was equally attractive to D. frauenfeldi as cue-lure. Using traps baited with cue-lure or methyl eugenol in 5 ecosystems, the highest numbers of males of D. dorsalis, D. umbrosus, D. frauenfeldi and D. caudatus trapped were from a village, on a vegetable farm for D. cucurbitae, and D. occipitalis was only caught in a forest. Analysis showed that for each species of Dacus the difference between ecosystems was highly significant. The few examples caught in grassland were probably migrants.