The startling and unfortunate demise of bees
Home & Garden

The startling and unfortunate demise of bees

IT is one of the ravishing ironies of gardening that we deal with ever-changing seasons and transient material.

And yet our impulse is to fix it, or at least to control and maintain it. But the more we put into our gardens the harder it becomes to relinquish them.

Often, the garden throws up startling events, completely beyond our control or even comprehension.

Nothing throws this into focus more sharply than the vexatious business of destructive nature.

Let me explain.

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Every year, in a nearby walled garden, when the scented blooms of a large lime tree are at their most floriferous, I have seen around its base bees in their dozen, some intoxicated it would seem, many already dead and withering in the humidity.

More were being taken by birds and marauding wasps, and whilst the bumble bee outnumbered the honeybee by ten to one, the sight was one of great sadness.

The reason is as follows.

All lime trees (Tillia species) are extremely attractive to bees when they come into flower, but for honeybees the lime tree known as Tilia petiolaris, can be a fatal attraction.

Lime tree flower nectar consists of a mixture of sugars along with a significant quantity of a sugar called mannose.

The bees are unable to metabolise this sugar fully and it becomes irreversibly bound to the digestive enzymes in their gut.

The available enzymes soon become used up, making the digestion of other sugars impossible and so the bee dies of sugar starvation, even though its stomach may be full.

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Fortunately, T. petiolaris flowers in late July and early August when bee colonies are at peak strength and as such are better able to survive the loss of those foraging among the branches.

Humans can digest mannose so there is no danger from eating honey produced from lime nectar.

The pendant silver lime tree blossoms may still be hanging heavy due to the weighty crawling of foraging bumble bees, but the sooner flowering ceases, the better for all these important, furry pollinators.

Varroa mite has decimated honeybee stocks in recent years so every single honeybee and bumble is valued for their ability in pollinating crops of every kind.