Ruud Kleinpaste: Bumblebees are ready for winter

A few months ago, we chatted about the bumblebee project started at Tekapo School. The kids and teachers created some raised beds full of flowers that attract bumblebees. We have four species here in Aotearoa. The big ones (Buff-tailed bumblebee) are the most common species and also the best pollinators we’ve got (kiwifruit, melons, blueberries, broad beans, etc). These insects are so important in our gardens! For me they are the crucial pollinators on my tomatoes (and capsicums) in the tunnel house. The irony is that tomatoes do not produce nectar (to attract pollinators), instead bumble bees are lured to tomatoes for the pollen they can dislodge by vibrating the flowers (a buzz-movement!). You could also pollinate your tomatoes by using an electric toothbrush that shakes the tomato flowers, but to be honest, I can’t be bothered with that. Buzzing is achieved by vibrating the thoracic muscles very fast while leaving the wings in “neutral”. That same trick allows the hibernating queens to warm themselves up on the coldest mornings of winter. Bumblebees are different from Honeybees in a number of aspects: they do not have a “hive” and don’t gather a lot of nectar. Their colony is usually small (≈100-150 individuals), and last no more than one summer. That’s it! Now is the crucial time for the colony to look after the bumbles’ next generation: you see the Gynes (next generation queens) mating with male bumblebees. The fertilised queens will then look for a suitable place to hibernate – a place that could become the nest site for next spring: dry and dark and able to be excavated. The kids at Tekapo school are inserting small holes in the steep banks around the playing field. Alternatively, they make some small wooden “nest sites” in sheltered areas, hoping that the fertilised queens use those as their winter abode. I reckon that gardeners could create suitable holes like that to attract these pollinators – under a tree trunk, in deep, dry mulch at the base of a sheltering tree. I am trialling a wooden bumblebee box in the shade of trees and shrubs; inside that box is a heap of botanical material from an old mouse-nest. I was told that the overwintering bumblebees seem to love the small of that old mouse nest and their poos. I suppose that’s the way they find their shelter sites in Nature too. And here’s hoping I get a new colony of bumblebees in the garden before winter, so that the queen boss can raise my pollinators for spring this year… LISTEN ABOVE