Mango Aroma Triggers Different Reactions in Fruit Flies and Their Parasites

Jenn Hoskins
8th May, 2024

Mango Aroma Triggers Different Reactions in Fruit Flies and Their Parasites

Image Source: Natural Science News, 2024

Key Findings

  • In sub-Saharan Africa, the marula fruit fly prefers mangoes, especially the Kent variety, due to the fruit's scent
  • Parasitoids show varied attraction to mangoes based on the fruit's ripeness and infestation level
  • Chemical analysis of mango scents could lead to eco-friendly pest control methods
In the realm of agriculture, the battle against pests is a constant and evolving challenge. One such pest, the Ceratitis cosyra, commonly known as the marula fruit fly, has long been a bane to mango farmers in sub-Saharan Africa. However, the introduction of Bactrocera dorsalis, another fruit fly species, has shifted the dynamics of pest management. Researchers at the International Centre of Insect Physiology and Ecology (icipe) have delved into this issue, focusing on the interactions between C. cosyra, mangoes, and their parasitoids[1]. The study aimed to unravel the complex tritrophic interactions – those involving a plant, herbivore, and natural enemy – by examining how C. cosyra and its parasitoids, including the native Psyttalia cosyrae and the exotic Diachasmimorpha longicaudata and Fopius arisanus, respond to the scents emitted from mangoes in various states of ripeness and infestation. C. cosyra showed a marked preference for both infested and uninfested mangoes, with a particular fondness for the Kent variety. This could be due to the chemical cues or volatiles emitted by the mangoes, which serve as signals that guide the fruit flies to their potential hosts. These findings align with previous research indicating that C. cosyra is a significant pest for mango farmers[2]. The parasitoids, on the other hand, displayed varying preferences. Fopius arisanus was more attracted to mangoes infested with C. cosyra, while P. cosyrae and D. longicaudata showed a significant preference for mangoes in the later stages of infestation. This suggests that the parasitoids can detect and respond to the changes in mango volatiles over time, which could be pivotal for the timing of bio-control measures. The researchers used gas chromatography-mass spectroscopy to analyze the volatile compounds from the mangoes. They discovered that esters, a type of chemical compound, were predominant in non-infested ripe mangoes and those in the later stages of infestation. In contrast, monoterpenes and sesquiterpenes were more dominant in other conditions. These compounds are known to play a role in plant defense and attraction of both pests and natural enemies. Understanding the chemical profiles of mango volatiles is crucial because it can lead to the development of semiochemicals—substances that affect the behavior of insects. These semiochemicals could be used to lure pests into traps or to repel them from crops, thereby providing farmers with an environmentally friendly tool for pest management. This study builds upon earlier research that examined the desiccation resistance and water balance traits of C. cosyra, highlighting the physiological adaptations that enable its survival under varying environmental conditions[3]. It also provides additional context to the displacement of C. cosyra by B. invadens, as observed in previous studies, which suggested that the invasive species outcompeted the native one through faster larval development and aggressive adult behavior[2]. The icipe study not only adds to our understanding of the ecological interactions between fruit flies, their host plants, and natural enemies but also informs integrated pest management (IPM) strategies. By identifying which mango volatiles are most attractive to C. cosyra and its parasitoids, researchers can design targeted bio-control methods that exploit these natural behaviors. Furthermore, the study's insights into the chemical ecology of fruit flies and parasitoids could help refine autodissemination techniques, which involve using pests to spread pathogens like the entomopathogenic fungus Metarhizium anisopliae among their populations[4]. This fungus reduces the reproductive potential of infected fruit flies, further contributing to pest control. In conclusion, the icipe study sheds light on the intricate relationships between fruit flies, their host mangoes, and bio-control agents. By dissecting the chemical conversations within this tritrophic system, researchers are paving the way for more sophisticated and sustainable pest management solutions that could significantly benefit mango production in Africa and beyond.

FruitsEcologyPlant Science

References

Main Study

1) Mango headspace volatiles trigger differential responses of the mango fruit fly Ceratitis cosyra and its parasitoids.

Published 15th May, 2024 (future Journal edition)

https://doi.org/10.1016/j.heliyon.2024.e30068

Related Studies

2) Evidence for competitive displacement of Ceratitis cosyra by the invasive fruit fly Bactrocera invadens (Diptera: Tephritidae) on mango and mechanisms contributing to the displacement.

Journal: Journal of economic entomology, Issue: Vol 102, Issue 3, Jun 2009

3) Physiological mechanisms of dehydration tolerance contribute to the invasion potential of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) relative to its less widely distributed congeners.

https://doi.org/10.1186/s12983-016-0147-z

4) Horizontal Transmission of Metarhizium anisopliae in Fruit Flies and Effect of Fungal Infection on Egg Laying and Fertility.

https://doi.org/10.3390/insects4020206


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