For the last few days - I’m writing these notes in mid-October - I’ve been intrigued by a very smart, queen buff-tailed bumblebee who is visiting the salvia flowers in my garden. She’s a hefty insect and so she looks very clumsy when she tries unsuccessfully to force her way inside the lip of each long, narrow flower to drink nectar. But this bee is canny. Instead, she bites a hole at the base of the flower near to the nectaries, a short-cut to an energy-filled meal. However, the anthers holding the pollen are at the salvia flower’s mouth and she bypasses these, avoiding fulfilling her part of the deal, which is to pollinate the plant. It’s bumblebee 1 - salvia 0!
Thieving bumblebees
Buff-tailed bumblebee taking nectar from Salvia guaranitica by Brett Westwood
Discover why bumblebees aren't keeping up their end of the bargain in Brett's garden...
Buff-tailed bumblebee taking nectar from a Salvia by Brett Westwood
I’m fascinated by this behaviour because I wonder how she knows how to become an expert robber without watching other bumblebees. Although I’ve seen other buff-tailed bumblebees do this in summer, they are long gone and she has had to work things out for herself. Is flower-robbing an instinctive behaviour or passed on genetically or is she just a gifted bumblebee?
On Day 2 (October 8) she appears with her pollen baskets full of golden pollen, not from the salvias but from another unknown flower. This is very strong evidence that she is founding a colony nearby and is taking pollen back for the young grubs, which will become workers. Normally the local queen bumblebees sleep through autumn and winter and found their colonies in spring but it looks as this queen is carrying on as normal because there are enough autumn flowers to sustain her and her brood.
On Day 3 (October 9) the plot thickens. A fresh worker buff-tailed bumblebee appears at the salvia clump, proving that there is a nest nearby. Is this evidence of a second autumn colony? I will keep watching!
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