For the last few weeks the lack of bumblebees around the rosybee site has been very noticable. I have had feel like a fraud to several groups of visitors, trying to convince them that my beautiful colourful research border really is full of bee- attracting plants.
There may genuinely have been a drop in numbers but I think its much more likely that its due to the 6 (!!!!) hot dry weeks we have had. This will have two impacts:
- simple lack of nectar in the plants due to lack of moisure in the ground
- bumblebees dont really like it this hot and may be cowering in the shade
....and thirdly, I was expecting a shortage of buff-tails as we had so many vestal cuckoo bumbles last year which would have impacted the buff-tails reproduction.
I think its a combination of these factors as I have occassionally put the sprinkler on the border - when its got to the point of plants wilting - and have not noticed more bumblebees the following day.
So, who is pollinating all the plants this year? Honey bees! The adaptable little things have had an unchallenged pick of the plants and I have seen them on several flowers that I would previously have said where only a bumblebee choice. Solitary bee numbers seem unaffected but the year-end data will confirm.
It will be very interesting to see if bumblebee numbers pick up when the weather cools down.