Honey bee may pose threat to native bees
A Curtin University study has found the introduced European honey bee could lead to native bee population decline or extinction when colonies compete for the same nectar and pollen sources in urban gardens and areas of bush.
The research found competition between native bees and the introduced European honey bee could be particularly intense in residential gardens dominated by non-native flowers, and occurred when the bees shared the same flower preferences.
Under these conditions, it would appear that European honey bees – being very abundant and effective foragers with the ability to exploit a wide range of flowers – can outcompete native bees for nectar and pollen resources. Native bees are valuable pollinators of many crops, from macadamias and mangos to tomatoes, blueberries and watermelons. In some cases, they can be more effective pollinators than honey bees.
Lead author, Forrest Foundation scholar Kit Prendergast, from Curtin’s School of Molecular and Life Sciences, says the research was conducted over two years in urban gardens and areas of native vegetation on the Swan Coastal Plain at Perth, and revealed a complex relationship between native and introduced bees.
“Not all native bee species were impacted, but when native bees preferred the same flower species as honey bees or were of larger size – meaning they needed more food – this was when honey bees had a negative impact on native bees,” she says. “This occurs due to resource competition, where honey bees were more successful at exploiting food resources from flowers, leaving not enough nectar and pollen to support native bee populations.”
Strength in numbers
Unlike native bees, honey bees live in colonies of tens of thousands, and are better at telling their mates where flower patches are. This communication is done by using a combination of movement and vibrations known as the “waggle dance”, as well as using scent.
“Competition from honey bees was particularly fierce in residential gardens where there are lower proportions of the native wildflowers that our native bees have co-evolved to forage on,” Prendergast says. “This impact of competition with a super-abundant, domesticated and feral introduced bee, when combined with pressures from habitat loss as a result of increasing urbanisation and agriculture, especially livestock agriculture, places some native bee species at risk of becoming endangered or even extinct.”
What you can do to help
Prendergast says planting more flowering plants, particularly those preferred by vulnerable species of native bees, could help prevent them from declining in number. Controlling the density of honey bees would also be critical in reducing the pressure on native bees.
“Native bees are an integral and important part of any ecosystem, including in the Southwest Australian biodiversity hotspot in which our research was conducted,” Prendergast says. “European honey bees pose an added threat to many native bee species already at risk of declining numbers or even extinction due to increasing urbanisation.”
For more information on what to plant in your own garden to help our native bees, download Bee Friendly: a free planting guide for European honey bees and Australian native pollinators, thanks to AgriFutures Australia.