Story by Kit Prendergast
Bees are the most important of pollinating insects – without them, fruit and vegetable production would be severely compromised, many beautiful flowering plants would go extinct, and overall the world would be worse off for all creatures, including humans. There is nothing more delightful than having bees in your garden, in particular, native bees.
In the media of late there has been much attention about bee die-offs and pollinator declines, however the focus has been on the wrong species: the European honeybee. Despite claims, honeybees are actually doing OK – they are one of the most abundant and widespread species on the planet. In Australia they are doing especially well as, for now at least, the parasitic mite Varroa and the diseases it carries are absent here. Moreover, the European honeybee is actually an introduced species, and, for feral colonies, has even been considered to be an invasive species and listed as a threat to native wildlife. The species that we should be concerned about are our native bees. There are in fact about 2,000 species of native bees. Although sadly and most concerningly there are no programs involved in ongoing monitoring of native bee populations, we do know that they have suffered loss of habitat, especially for livestock agriculture. Fortunately, all of us can help preserve these precious pollinators. Apart from dietary changes, we also can help native bees through planting bee-friendly flowers in our gardens.
Bees of all species are entirely reliant on flowers for food. Across all stages of their life, from larva to adult, they need flowers. Nectar supplies the adults with energy, as well as the larvae, and pollen provides the developing offspring with the protein, vitamins and minerals, fats, as well as some carbohydrates. Now, not all flowers are equally good resources for bees, and not all bees will prefer the same flowers. This means that not only how many, but what particular flowers you plant are important when it comes to providing for bees. There are various “bee-friendly” flower guides circulating on the internet, but the problem is that most of these are tailed for honeybees. Honeybees are not too fussy when it comes to what they’ll forage on – as evidenced by how they’ve colonised environments across the world, they can and will forage on an incredible diversity of flowering plants. Not so for native bees, especially many in Australia.
The Australian continent has been isolated from other continents for millennia. This long age of geographic isolation has set the stage for a long period of co-evolution between the flora and fauna, without any outside influences. Australia is renowned for its unique, wacky animals found nowhere else in the world, and its native bees are no different. Many have specialised to forage only on a limited set of Australian plants (very patriotic). Plant your typical garden fare of ornamental plants popular in European gardens and they won’t be interested. Instead, to attract native bees to your garden, go native!
One of the most important plant families for native bees is Myrtaceae. This is the largest family of flowering plants in Australia, and includes our iconic eucalypts, bottlebrushes, mallees, and Melaleucas. So native bees sure do like “A home among the gumtrees.” During peak bloom these plants produce a profusion of blossoms literally dripping with nectar, and packed full of pollen. As woody trees, they also provide habitat for native bees that nest in pre-made cavities in wood created by wood-boring beetles. Another important family is Fabaceae, commonly known as pea plants or legumes. Native pea plants include the genera Hardenbergia, Daviesia, Hovea, Jacksonia, Gompholobium, and Dillwynia. Native pea plants are highly preferred by many Megachile and Trichocolletes bees. Being pea plants, like all Fabaceae, species in this family have a symbiotic relationship with nitrogen-fixing bacteria (Rhizobium species), meaning that they can grow in nitrogen poor-soils, and also often have highly-nutritious pollen. These two plant families dominate Australia in terms of both the number of species, and their geographic coverage. It’s no wonder then that so many native bee species have evolved to prefer, or even forage exclusively on, plants in these families.
Other important plants are native daisies (plants in the family Asteraceae, such as ‘Everlastings’) – another large family. Fan-flowers (Scaevola), and species in genera Hibbertia, Eremophila, Hemiandra, and Plectranthus are also frequently visited by native bees. Some plant species are highly reliant on native bees for their pollination owing to having poricidal anthers: anthers that only release pollen when vibrated at a particular frequency. Such plants that require “buzz pollination” include flax lilies (Dianella) and Solanum.
Rather than just planting one of these species, it is best to plant a range to cater to the needs of as many different native bee species as possible. Some species are adapted to forage on flowers of different shapes. Bees obtain nectar through licking it up with a glossa (essentially a bee tongue). The length of the bee’s tongue therefore dictates whether it can access the nectar. Some flowers are relatively long and tubular, and to access the nectaries at the base, only bees with relatively long tongues, such as Amegilla can feed on them. Shallow, open flowers like many Myrtaceae blossoms in contrast can be easily accessed by small bees with short tongues like Hylaues.
Bigger patches are also better – an isolated daisy is unlikely to be a salient signal for bees. Remember, these little creatures have to venture from their nests into the big wide world and traverse the land to locate their preferred resources in sufficient quantities. Large patches of bee-friendly flowers represent both a large amount of food to meet a bee’s requirements, but also are easier for the bee to discover.
Different bee species are also active at different times of the year. Depending on the species, their activity period may cover just a few weeks, to all of the year. This means we should try and have bee-friendly plants in bloom throughout the year, so again, selecting a number of species that bloom at different times can ensure that a variety of bee species are catered for.
Native bees are stunning creatures, and it is so rewarding to have them buzz about your garden. With the right selection of native flowers, you can turn your garden into a bee haven.