What fly guts could reveal about our health

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Diet choice, reproduction of fruit flies affected by gut bacteria

Two Macquarie researchers are co-authors on a pair of intriguing papers about fruit fly gut bacteria.

The two new studies reveal that the gut bacteria composition of the common fruit fly affects consumption as well as reproductive behaviour.

The discoveries provide an exciting illustration into how of how microbes can influence the behaviour of host animals, which could be important for understanding gut microbiota and cognitive function in humans in the future.

Dr Fleur Ponton, is the last author on both studies and is based at Macquarie University’s Department of Biological Sciences.

“Beyond the biomedical significance of this research, there are potential interesting applications in the context of invasive and pest species control,” she says.

Macquarie University has a long history in pest control and hosts the Australian Research Council Centre for Fruit Fly Biosecurity Innovation.

The papers were co-authored by researchers from Macquarie University’s Department of Biological Sciences and the University of Sydney’s Charles Perkins Centre and report that that the gut microbiota of the common fruit fly has a significant effect on their foraging behaviour and reproductive success, and that its influence can be carried down to the next generation.

Published in Current Biology, the study into foraging behaviour manipulated the type and timing of bacteria individual flies were exposed to, and examined their olfactory-guided preferences to food microbes and nutrients.

In addition to foraging for nutrients to achieve a balanced diet, the researchers found flies also forage for bacteria to populate a healthy gut flora. Responding to smells associated with particular bacteria in foods, the flies showed a distinct preference for more beneficial types of bacteria over less-beneficial types or food lacking the bacteria.

In a separate study, published in Biology Letters, researchers inoculated flies with different types of microbes to observe the consequences of changes in the gut bacteria composition of sexually interacting fruit flies.

They found the reproductive investment and success of a mating pair was influenced by gut bacteria, as well as the body mass of offspring.

Lead author Dr Juliano Morimoto, now at Macquarie University, says the findings reveal the effect of gut microbiota on reproduction, but also suggest these effects can be carried over to the next generation.

“Given the importance of the gut microbiota in physiology and health, our findings reveal important and long-lasting effects of gut bacteria on reproduction and offspring traits,” he said.

“As understanding of the gut microbiome and its effect increases, the potential for breakthroughs in understanding broader health impacts increases too.”

Professor Stephen Simpson, Academic Director at the Charles Perkins Centre and a co-author on both papers, said, “This demonstration that bacteria in the gut influences foraging and reproductive behaviour is of particular interest for further research.”

The two studies involved researchers from Macquarie University, The University of Melbourne, Oxford University, University of Florida, Federal University of Parana, University Paul Sabatier.

Thank you to Rachel Fergus at The University of Sydney for her contribution to this story.

Read more about the gut microbiome at http://sydney.edu.au/charles-perkins-centre/our-research/current-research/nutrition/gut-microbiome.html

Read more about pest control at fruitflyittc.edu.au