Researchers at the University of New England have identified two fly species as promising pollinators for berry crops, offering a vital alternative to European honey bees in protected cropping systems.
Lead researcher, Dr Abby Davis, used in-field cages to study the pollination capabilities of two Australian fly species, the brown blow fly (Calliphora stygia) and the drone fly (Eristalis. tenax) in commercial blackberry and raspberry production.
“We found both species were able to successfully pollinate berry crops,” says Dr Davis.
“However, the drone fly consistently produced higher-quality fruit, particularly in blackberry, and there was no impact on the size or quality of fly-pollinated berries when compared to bee-pollinated berries under natural field conditions.
“The brown blow fly was less effective on its own, sometimes producing lower-quality fruit, but as a flower visitor, it still has potential to complement more effective pollinators such as honey bees, stingless bees, and now drone flies.”
To build on these findings, the research was scaled up to full-sized commercial polytunnels, looking at the drone fly’s capabilities across both winter and spring production seasons.
These trials revealed that drone flies can maintain higher levels of foraging activity on blackberry flowers, deliver effective pollination, and produce high-quality fruits within enclosed commercial farm polytunnels.
“The drone fly pollinates commercial blackberry at a level comparable to managed honey bees, and in some cases can even outperform them under protected cropping conditions,” says Dr Davis.
“The flies were also more active on flowers during cooler temperatures when honey bee activity is often reduced, which could improve pollination reliability in colder areas and bolster crops facing unusual weather conditions.”
As global agriculture faces increasing challenges from climate variability, pollinator shortages, and over-reliance on managed honey bees, finding alternative, or supplementary, pollinators has never been more pressing.
“Pollination is fundamental to agriculture, but over-reliance on managed honey bees can leave crops vulnerable,” said Dr Davis.
“Identifying alternative and complementary pollinators is key to ensuring stable production under changing environmental conditions.”
While flies might not seem like an obvious pollinator, they share several similarities to honey bees.
For example, drone flies have hairy bodies, which is perfect for trapping and transporting pollen, and their diet is made up of floral resources such as nectar and pollen.
“Flies tend to get a bad reputation because the ones we notice are the ones that bother us, but many of the species we study are flower visitors – they often look like bees, go largely unnoticed, and play an important role in pollination.”
While the study provides a strong launchpad for the introduction of flies as commercial pollinators, future research will focus on their viability for other crops, and their effectiveness in different field conditions.
“Further research is needed to refine fly deployment practices, assess pollination performance across different environments, and understand how managed flies interact with wild pollinator communities,” said Dr Davis.
“Expanding this research to test additional fly species, crops, and production systems will be essential for realising the full potential of flies in sustainable, climate-resilient agriculture.”
You can read the full study here.
Source: Scimex
