Identification of Economically Important Fruit Fly Larvae of Dacini (Diptera: Tephritidae) in Thailand using Scanning Electron Microscopy (SEM)

Abstract

Fruit flies are of prime economic and quarantine importance throughout the world. Their larvae infest fruits and cause serious problems in international and sometimes domestic trade. Morphological similarity among larvae of different species has made identification of larval stage based on morphological characteristic very difficult. The present paper reports on the use of scanning electron microscopy (SEM) to improve the precision and efficiency of species identification of fruit fly larvae. Larvae were collected during surveys of fruit orchards in all regions of Thailand during 2016-2018 in from which 120 specimens of 6 species were collected. Studies were focused on the six dacini fruit flies of greatest economic importance in Thailand including: Bactrocera carambolae, B. correcta, B. dorsalis, B. latifrons, Zeugodacus cucurbitae and Z. tau. A dichotomous key was prepared to enable initial identification of larvae by using a combination of morphological features. However, further phylogenetic analysis is needed to clarify the distinction among other species.