May 19, 2022 2 min read
The month of May was chosen for World Bee Day because the northern hemisphere is in spring; with bees becoming more abundant, and in the southern hemisphere it’s a time when hive products are harvested. The specific date is the birthdate of the pioneer of modern beekeeping, Anton Janša (1734-1773).
We ’re all encouraged to contribute the preservation of bees and other pollinators by supporting beekeepers. How? Well we can buy honey and hive products locally, educate the next generation on the importance of bees, and to preserve wildflower meadows which have a high diversity of nectar-bearing plants. This hit UK headlines this month as people were asked to participate in ‘No Mow May’. to highlight the benefits of leaving the mower in the shed for another month and letting the native wildflowers grow. We all know that wildflowers are a great source of nectar for insects, and that we should plant more pollinator friendly plants, or leave wild areas. We’ve written about it in plenty of previous blogs, this one most recently.
But are there non-friendly plants for pollinators?
There are some, but luckily these don’t tend to be found in the UK.
The exceptions are the Tilia tomentosa (silver lime) and rhododendrons.
Rhododendrons contain a toxin that deters and can kill honeybees in just a few hours, but bumblebees remain unaffected. Interestingly, as rhododendron toxins are also fatal to humans, there are recorded uses of ‘mad honey’, made from the nectar from these plants being used in ancient warfare as a chemical weapon.
The silver lime is a more complicated example. Initially, like the rhododendron, it was thought that the nectar contained toxins that were too much for the bees. However, that has since been debunked. There’s a theory that the caffeine present in the nectar may be changing the bee’s behaviour, causing them to run out of energy and starve, but this has also not been fully established as the cause of dying bees under lime trees.