Documentation of tephritid fruit fly (order diptera) from South-Western Sarawak, Malaysia :|bdistribution, population dynamics and verification of identification keys of Rohani and Abdul Ghani (1990)

The tephritid fruit flies rendered infested fruits unmarketable by leaving puncture marks on the fruit’s skin and by feeding of the larvae on the fruit flesh inside. The status of these fruit flies has not been updated since 1995 until recent years. Therefore, this study was conducted as part of the latest efforts to update the status of fruit flies in Sarawak and their association with fruit trees, as their host plants. The study was conducted in 33 selected study sites within Kuching and Samarahan Divisions. Adult tephritid fruit flies were collected using pheromone traps with methyl eugenol as attractant and by rearing them from larvae collected from infested fruits. From this study, six species of tephritd fruit fly: Bactrocera (Bactrocera) albistrigata (de Meijere), B. (B.) dorsalis complex, B. (B.) umbrosa (Fabricus), B. (Hemigymnodacus) diversa (Coquillett), B. (Zeugodacus) cucurbitae (Coquillett) and Taeniostola vittigera (Bezzi) were successfully sampled from Kuching and Samarahan Divisions. B. dorsalis complex, comprising of two common species: B. (B.) carambolae (Drew and Hancock) and B. (B.) papayae (Drew and Hancock) was the most abundant and common species found within the study area. Two species, B. diversa and T. vittigera, recorded from Mangifera torquenda (lamantan) and Bambusa species respectively, were new record for Sarawak. B. dorsalis complex were also commonly found to attack most of the sampled fruit trees including the introduced species, Eugenia stipitata (yellow araza) and Thevetia peruviana (yellow oleander); forest species: Poikilospermum suaveolens (mentawan) and Lagerstroemia speciosa (banaba) which were new record for Sarawak. B. dorsalis were also associated with multiple host plant family (29), same as B. umbrosa but in lower number (13). B. albistrigata, B. cucurbitae, B. diversa and T. vittigera were associated with single host plant family. Rearing fruit flies from Coffea arabica (coffee), vii Capsicum annuum (red chili) and Lagenaria leucantha (bottle gourd) to name a few, were unsuccessful. The population monitoring of B. dorsalis complex showed their presence all year round. They were more abundant at Semongok Agriculture Research Centre (SARC) compared to at Rampangi Agriculture Research Station (RARS). The number of emerged adult of B. dorsalis complex, reared from guava fruit (Psidium guajava), with sex ratio of male to female almost 1:1 (51: 60), correlated positively with the fruit size. This suggested that the bigger fruit provide enough food for full development of larvae to adult stage with one larva calculated to consume an about 6- 7 g of fruit. The characters of Bactrocera species used in the identification key by Rohani dan Abdul Ghani (1990) were tested using cluster analysis and were found to be reliable for morphological identification of tephritid fruit flies in this study. The documentation of tephritid fruit flies provide new and additional knowledge about this pest especially collected from south western part of Sarawak. Similar study for whole Sarawak would provide better benefit for monitoring tephritid fruit flies of Sarawak in the future