Differential responses of Bactrocera dorsalis and its parasitoids to headspaces of different varieties of tree-attached mango fruits and the associated chemical profiles

Abstract

Bactrocera dorsalis (Hendel) is a major pest of fruits and vegetables worldwide with documented losses of up to 100%. Various management techniques including the use of parasitoids, such as Fopius arisanus (Sonan) and Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) within the context of the Integrated Pest Management (IPM) approach have been deployed for its control. The effectiveness of parasitoids is well understood, but knowledge of the semiochemicals that mediate their behavior, as well as that of the host fruit fly to tree-attached mangoes, is lacking. Here, we first compared the attractiveness of the above-mentioned fruit fly and its parasitoids to volatiles of different treatments (non-infested physiologically mature unripe and ripe mangoes, mangoes newly exposed to ovipositing B. dorsalis, and mangoes on day 7 and day 9 post-oviposition) of tree-attached Kent, Apple, and Haden mango varieties relative to control (clean air). The fruit fly was significantly more attracted to the mango volatiles (up to 93% of responsive insects) compared to the control (clean air). Fopius arisanus was significantly more attracted to mangoes with ovipositing fruit flies (68–76%) while D. longicaudata was significantly more attracted to day 9 post-oviposited mangoes (64–72%) compared to the control. Secondly, we elucidated the headspace volatile profiles of the non-infested and infested tree-attached mangoes using gas chromatography linked to mass spectrometry (GC-MS). The volatiles revealed various types of organic compounds with qualitative and quantitative differences. The majority of the compounds were esters making 33.8% of the total number, followed by sesquiterpenes-16.4%, and monoterpenes-15.4% among others. Most compounds had higher release rates in headspace volatiles of fruit fly-infested mangoes. Lastly, we harvested the infested mangoes and incubated them for puparia recovery. The number of puparia recovered varied according to the mango variety with Apple mango registering 81.7% of the total, while none was recovered from Kent. These results represent the first report of the changes in the headspace components of non-infested and infested tree-attached mangoes and the associated differential responses of the mentioned insects. A follow-up study can reveal whether there is a convergence in olfactomes which is significant when developing baits that selectively attract the fruit fly and not its natural enemies and fill the knowledge gap from an evolutionary ecological perspective.

The Variation of Oviposition Preference and Host Susceptibility of the Oriental Fruit Fly (Bactrocera dorsalis Hendel) (Diptera: Tephritidae) on Commercial Mango Varieties

“…The origin of B. dorsalis is Asia [5], and the species is currently distributed across Asia, Africa, and the Pacific regions [6,7]. B. dorsalis is a serious pest because its females have a wide host range and a high reproductive rate [6], and it prefers to attack mango fruits [5,8], causing high post-harvest damage.…”

“…Female fruit flies puncture the peel of the host fruit using their ovipositor, then deposit eggs into the pulp of the fruit, where the larvae hatch and feed on the fruit pulp, causing serious direct damage and making fruits unfavorable for consumption [12]. The fruit damage of B. dorsalis is also influenced by the fruit variety and its physiological characteristics [5,8,13,14]. Boinahadji et al [15] recorded that the oviposition preference and offspring emergence of B. dorsalis are high in mangoes, with a shorter development time relative to seven other fruits tested in their study in Senegal.…”

CRISPR/Cas9 Ribo nucleoprotein complex‐mediated editing of the OBP13 gene affected the response of male Bactrocera dorsalis (Diptera: Tephritidae) to methyl eugenol

“…Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) is one among the catastrophic Tephritids (Boinahadji et al., 2020) capable of achieving up to 100% yield loss if management measures are not adopted (Miano et al., 2022). As these flies are ambiguous endophagous feeders, dispersive, efficient fliers with highly suited ovipositional behaviour of females to lay eggs deeper into the fruit mesocarp confer the chemical control less efficient and lead to resistance to insecticides.…”