I love the end of winter. It’s as though, just when the icy mornings seem like they’ll never end, native flowers burst out and practically sing at us that the wait is over and we’re heading into spring. Wattle bursts out bright and golden all over the place. Brilliant red banksias droop down to the ground, surrounded by pale green leaves. Buzzing bees flit between flowers, wiggling their bright blue bums as they forage for nectar.
…Wait a minute…
If, like me, when someone says bee you mentally picture something like this:
…then the thought of a bee with a blue bum may be a bit surprising. Bees are yellow, right? Black and yellow, to be more specific. What’s more iconic in the bee world than the image of the yellow, fuzzy honeybee Apis mellifera? As iconic as this image is, it turns out that it only became part of the Australian landscape as recently as 190 years ago, and clearly didn’t get here on its own! The European honeybee (Apis mellifera) was introduced to provide a reliable source of honey for colonisers. The fact that they even survived the journey is pretty impressive – after all, there are notoriously few flowers in the ocean! While early Europeans may not have intended for bees to escape into the environment, inevitably it happened. Decades later, they’ve made themselves at home across virtually the entire continent. Managed hives of European honeybees continue to pollinate many of Australia’s crops, and the value of pollination and honey services from these hives is estimated to be in the billions.
As well as our crops, European honeybees visit our native plants. This results in some pretty delicious (and uniquely Australian) honey flavours, but it begs the question, what is the impact of these bees on our native pollinators?
Australia has an amazing diversity of bees, with over 1,500 species of native bees. In northern, tropical regions of the country, social species of stingless bees are commercially sold as pollinators and honey producers. However, the majority of our native species are peaceful, solitary creatures, with a variety of interesting behaviours.
Victoria is home to seven of the ten major groups of native bees – reed bees, blue-banded bees, teddy bear bees, leafcutter bees, resin bees, masked bees, and Homalictus bees. The behaviour of these groups is incredibly diverse. For example, the small but beautiful Homalictus bees have large, intricate branching nests, some of which house many females that all take turns guarding the nests from intruders. Those familiar with leafcutter ants may have a clue as to the behaviour of leafcutter bees, which cut disks out of leaves and use them to build their nests.
My personal favourite, resin bees collect resins and gums for their brood cells and nest holes, and on occasion may try to ‘borrow’ some resin from the nests of stingless bees. Some of these species are dazzlingly beautiful, with species of Homalictus bees ranging from golden-blue to coppery red. Others, such as masked bees and reed bees, are mainly black in colour, with only a few bright markings. One of the most dynamic of the bee groups, the blue-banded bees are delightfully rotund and have bright stripes of white or blue across their abdomens.
There has been a dramatic increase in the number of feral European honeybees in the last 80 years. As many of our native pollinating species have considerable environmental overlap with European honeybees, this spread could indicate considerable trouble for our natives. There has been a number of investigations analysing potential impacts of European honeybees; however, a review by Paini (2004) found that most of these studies suffered from confounding factors or low replication, making it difficult to ascertain how much of an impact invasive honeybees are directly having on native pollinators. As recently as 1992, the bumblebee species Bombus terrestris has inhabited Tasmania, spreading widely across the state in the short time it’s been there. While there is some evidence of displacement of native bees, the major concern is how B. terrestris increases seed production of invasive weeds, helping them to disperse further.
This seems to be the issue on the mainland as well: European honeybees are also fond of non-native plants like Scotch broom, resulting in a decrease in native flora and feeding opportunities for our native bees and pollinators. While the impact of invasive bee species may still be unclear, what researchers generally agree upon is that deforestation and loss of floral and nesting resources is one of the major concerns for our native bees. Clearing of land for agricultural use decreases their available habitats, whilst constant grazing can restrict the regeneration of particular plants, restricting their range.
All of this raises the question: how can we ensure our native bee species are preserved so that we don’t lose them forever, as has been seen in parts of Europe? One answer may be in commercial applications. For example, the blue-banded bee is currently being investigated as a potential pollinator for tomato plants, thereby eliminating the need for B. terrestris on the mainland. Another avenue is an increase in public interest. In the UK, the Bumblebee Trust has taken off in recent years, as the public became aware of their decreasing numbers and sought to save the species that remained.
In the last decade, the persistence of the drought has led to a push for Australians to plant native species in our gardens. Appreciation for our native flora has been slowly and steadily increasing. Combining this with an awareness for our native bee species could be a way of encouraging public engagement and enthusiasm for our natives, and ensuring their survival as factors such as climate change become increasingly unavoidable.
After all, who wouldn’t want to save our bright blue beauty?
Mary Shuttleworth is a Masters graduate from the University of Melbourne, where she pursued her interests in ecology and parasitology. She is interested in science communication, education and community engagement.
Find her on Twitter at @muttersworth.
Banner image courtesy of http://www.bellingenbees.org.au