#PolliNationSA | Bees and Biodiversity

Connal.Eardley
Published on August 2nd 2020
7
A small bird perched on a flower
Seasons change from year to year, some being dryer and some hotter than others.
Bee populations wax and wane as they cope with the weather and availability of suitable food plants – in severe droughts they appear to almost disappear.
A close up of a green leaf
Aphids
Apart from food availability, parasites and predators also affect population density. Such tendencies occur in many insect populations, such as the aphids in my garden. After the aphid populations grow large the hoverfly and ladybird beetles move in and decimate them.
Seldom does a plant have only one bee pollinator. They usually have many different pollinators, often closely related species. And different species predominate from one year to another. Therefore, it appears to me that ecosystems have networks of bee populations that wax and wane so that there are always some pollinators around.
A close up of a flower
Leafcutterbee taking a nectar meal. Elize Eveleigh
Insect populations are commonly dynamic, increasing and then decreasing in size. Always with some individuals that disperse to other areas to fill the void left by the demise of another species in that area, i.e., plants mostly have suits of pollinators that change from year to year. This is why biodiversity is so important, it creates resilience to change.
A pink flower on a plant
Hibiscus
Bees are highly mobile insects and they find new patches of suitable flowers. Long-horned-bees (Tetralonia, subgenus Eucara, which has short antennae), for example, visit only hibiscus plants. When I travel through the Karoo I find them around small patches of hibiscus flowers that are miles away from any other hibiscus. These plants grow next to the road around puddles dammed up by the road, so they are unnatural – but the bees find them.
Gardens also change from year to year, or at least mine does, as shrubs grow tall they shade out the ground covers. Therefore, to have a bee-friendly garden one would have to see that changes for bees also occur.
Buy a bee hotel for your solitary bees from Tutus Loco
Although gardens have a high diversity of flowers, and most have flowers throughout the year, it appears to me that a relatively small number of bees frequently visit gardens. I assume that it is due to a shortage of nesting habitat. This is because miners tend to like open patches of ground that is not tilled, bare embankments like those created by soil erosion, soil that is not frequently watered (that’s why one finds them in abandoned plant pots).
A close up of a flower
Carpenter bee on Polygala
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Carpenters like dead wood and stem-bees like hollow twigs. This is what we get rid of in urban areas when we tidy the garden. We, therefore, need to create and appreciate little ecosystems at home, untidy rather than manicured, because they bring so much more pleasure. This we should change.
A frog sitting on a rock
Dead wood stump

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