ABC Rural By Charlie McKillop
Posted 24 minutes ago
PHOTO: Tetragonula Carbonaria, aka native fly, has been shown to be the dominant pollinator of mango trees in a new study (Supplied: University of New England)
New research has shown native flies, not bees, are the top pollinators of mango trees.
Surveying of ten mango farms at Mareeba, in far north Queensland, has revealed up to 50 different insects came into contact with the reproductive parts of the flowers, including two bee species, nine flies and one beetle.
00:00 AUDIO: Dr Romina Rader's research shows flies - not bees - are the top pollinators of mango trees (ABC Rural)
Not only were flies shown to be the most dominant and frequent visitors of the mango flowers, they also proved to be highly effective at carrying pollen when compared with honey bees.
The native bee transferred on average seven pollen grains a visit, the blue blowfly about 6.8 pollen grains and the honey bee 2.7 pollen grains.
"So we knew (flies) had visited flowers reasonably frequently before, but to actually show they're actually up there with the bees in terms of the amount of pollen they move was really interesting," the University of New England's Romina Rader said.
Some of them were bringing in road kill from the roads outside their farms because they knew the flies had a larval stage that depended on these dead animals, so the farmers were already onto it.
Dr Romina Rader, whose study has revealed flies are top mango pollinators
"And most of the flies moved frequently between flowers and they're good at moving between trees down the road, so in terms of trying to cross-pollinate, they seem to be the ones that would be doing a good job."
And while the results might surprise many, Dr Rader said the survey confirmed the pollinating power of flies was already being harnessed by some growers.
"A lot of them already thought that flies were playing a role, just because they obviously know about their crops," she said.
"And some of them were bringing in roadkill from the roads outside their farm, because they knew the flies had a larval stage that depended on these dead animals, so the farmers were already onto it."
PHOTO: Insect sampling can be a meticulous and at times, tedious task but the results can be surprising(Supplied: University of New England)
Understanding diversity of insect communities
Dr Rader said surveying work would continue to further understand the variables that influenced the diversity and pollinating performance of various insect communities.
"It definitely depends on where you are geographically and also the type of farm management and resources you have available on the farm, because the life history characteristics vary a lot on these insects," she said.
"And also the weather; if you do your surveys on really cold or rainy days, you might find flies are more dominant than bees, because flies do better in cold weather than the bees do. Bees really need warm weather to get their energy resources for flying."
"...the flies and other species that are not bees are actually providing a service so trying to accommodate them in the orchard is really important."
Dr Romina Rader, University of New England
So what are mango growers to make of the new research in terms of maximise the pollination potential of their orchards? Dr Rader said it still was a case of different horses - or insects - for courses.
"Flies have really diverse life histories. so the ones that need dead animals are things like the green and blue blowflies," she said.
"But floral resources are really important for some larvae and for all of the adults to make sure they've got energy for reproduction etcetera, so I think that's the cool thing about them, it takes all sorts."
"In terms of what growers can do, I think just making sure that we acknowledge that the flies and other species that are not bees are actually providing a service, so trying to accommodate them in the orchard is really important."