Horticulture

Queensland fruit flies have a nose for trouble

Queensland_Fruit_Fly_-_Bactrocera_tryoni

A study published in Scientific Reports by Macquarie University Applied BioSciences has revealed that Queensland Fruit Fly (Q-fly) can detect the presence of potential predators by smell. Incredibly the study also found that Q-fly modify their behaviour based upon this detection, adopting predator specific responses.

In the study Q-flies were exposed to odours from four different predators (three spiders and an ant) and one non-predatory insect by blowing charcoal filtered air over the insects. The behaviour of the flies in four key areas was then observed namely, movement (motility), seeking food (foraging), egg laying (oviposition) and mating as each of these behaviours is essential for insect fitness.

PhD candidate and lead author Mr Vivek Kempraj stated that the flies showed a significant reduction in foraging, mating and egg laying activity in the presence of predatory insect olfactory cues. “Each of these activities is essential for insect survival and so the impact of the olfactory cues is noteworthy”.

The predatory insects also significantly influenced the movement of the Q-flies as well, with both increased and decreased movement rates, depending on species. Mr Kempraj suggests that “this may be due to the differences in the predation techniques used with a reduction in speed being advantageous to evade nocturnal predators whilst the opposite holds true for daytime predators”.

Additionally, Mr Kempraj remarked that “the flies used in our experiments had never previously been exposed to predators, which suggest that the behaviour responses must be innate rather than learned”.

Mr Kempraj reported that his work was an important part in developing our knowledge about predator – prey interactions in Q-fly other fruit flies and insects more generally. “The findings have the potential to influence our management of Q-fly as a pest insect. With multiple hosts across a range of commercially important crops, Q-fly is a significant threat to Australia’s horticulture industry, costing up to $300 million dollars in lost market opportunities each year, and advances in this area would be welcomed by industry”.

Head of Applied BioSciences Distinguished Professor Phil Taylor concurred noting that “The idea that fruit flies can smell and respond to their enemies, without ever coming into contact, is highly novel. This has not been found in any species previously and is a major step forward in our understanding of the relations between fruit flies and their enemies”.

This research has been delivered as part of the SITPlus collaboration project Raising Q-fly Sterile Insect Technique to World Standard (HG14033), funded by the Hort Frontiers Fruit Fly Fund, part of the Hort Frontiers strategic partnership initiative developed by Hort Innovation, with co-investment from Macquarie University and contributions from the Australian Government. Mr Kempraj was additionally supported by funds from the Australian Research Council Industrial Transformation Training Centre for Fruit Fly Biosecurity Innovation.

Source: Macquarie University