Oviposition by the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), on five citrus types in a laboratory

Abstract

Frugivorous insects use visual, chemical and tactile cues to find a suitable host for oviposition. However, these cues can vary greatly among fruit cultivars and condition, changing their susceptibility to fruit fly oviposition. The aims of this study were to (1) determine the effects of ripeness stage and damage on oviposition propensity by sexually mature, mated female oriental fruit flies, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), on five citrus types (species and cultivars) under choice and no-choice conditions and (2) describe the oviposition behaviour of B. dorsalis on ripe fruit of the same five citrus types that were either damaged or undamaged under no-choice conditions. All tests were conducted in the laboratory. The citrus types tested were Citrus sinensis (L.) Osbeck cv Delta Valencia orange, Citrus sinensis (L.) Osbeck cv Glen Ora Late navel orange, Citrus limon (L) (Burm.f.) cv Eureka lemon, Citrus paradisi (Macfad.) cv Star Ruby grapefruit and Citrus reticulata (Blanco) cv Nadorcott mandarin. Peel physical properties and essential oil composition were determined for each citrus type and stage. Oviposition propensity of B. dorsalis was significantly greater on damaged citrus but was not correlated with fruit diameter, peel thickness, oil gland density or oil gland size. A total of 45 aromatic compounds were found to be significant between the five cultivars investigated, and 6 of 11 compounds were significantly associated with over-ripe fruits. Bactrocera dorsalis spent a significantly greater proportion of time ovipositing in damaged citrus and showed higher aggression when oviposition occurred in undamaged citrus. These results suggest that the removal of damaged and fallen fruit is important for controlling this pest in citrus orchards.