Can pollinators survive sudden changes in the weather?

Snow-Warm garden comparison

Just how pollinators cope with sudden changes in the weather early in the season is a bit of a mystery.  Take 2018 as an example; my wife Karin spotted the first queen bumblebee in the garden on 6th January, investigating a camellia flower just outside the kitchen.  Over the course of the next few weeks I saw a few more at various sites, plus occasional hibernating butterflies such as the red admiral. The various social media outlets were reporting similar things, it looked as though we were going to have an early spring.

Then at the end of February “The Beast from the East” hit the UK, a weather system from Siberia that brought some of the coldest weather and heaviest snow the country had experienced for several years.  That persisted for over a week then things got much milder.  On 16th March I was in the garden and spotted the first male hairy-footed flower bee of the year, plus a mining bee (Andrena sp.), and a brimstone butterfly, and a queen bumblebee, and a red admiral.  Great I thought, spring really is here!  The next day it snowed.  A “Mini Beast From the East” had arrived, rapidly: the two pictures above making up the composite view of our garden were taken two days apart.

What happened to all of those insects I saw? Were they killed by the cold weather?  Or did they survive?  We have no firm data to answer that question – as far as I’m aware no one has ever tagged early emerging pollinators and followed their progress (I could be wrong – please let me know if I am).  It would make an interesting, though labour intensive, project but could be done using non-toxic paint of various colours to mark the insects.

I suspect that some of the pollinators I saw were killed, but most were not and simply went back into hibernation for a short period, hunkering down in safe, sheltered spots.  That makes much more evolutionary sense: any insects in the UK that cannot survive sudden changes in the weather would have gone extinct long ago.  Another clue to support this idea is the fact that plants in flower early in the season, and in some cases the flowers themselves, usually survive the cold weather and come back as if nothing had happened.  If the flowers can do it, and they have to stay where they are, surely the mobile pollinators can also do it?

As always I’d be interested in your thoughts on this topic, feel free to comment.  And while we wait for the UK to thaw, here’s some topical and rather catchy music to listen to – The Beelievers singing “Mr Gove”.

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9 Comments

Filed under Bees, Biodiversity, Butterflies, Gardens, Pollination, Urban biodiversity

9 responses to “Can pollinators survive sudden changes in the weather?

  1. This idea of tracking pollinators is interesting, but I was under the impression that recapture rates for insects were incredibly low and that this was one reason why we don’t have good population abundance levels for most insects. Are there good recapture studies for bees that you know of?

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  2. I have been pondering the same things myself, having seen my first solitary bees earlier this week whereas today it is snowing heavily for the second time in March. I suppose, as you suggest, that bees will just shelter, can they go back into hibernation for a few days? One pollen source that concerns me here is willow. There is one tree near where we live that is coming into full flower and is normally a mass of insects at this time of year. So far I have seen no insects as the weather has been poor and and some of the flowers are nearly over. An important pollen source may be lost for this year.

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  3. Murtagh's Meadow

    We have had similar weather fluctuations here in the west of ireland, though with less snow, but with the bitterly cold winds from the east. We usually see our first bees around rhis time in March, but we saw a couple of queen bumbles last week, when it was milder for a couple of days. Here in the west bees would usually have to worry about wet rather than cold and i have thought that they’d emerge, find some food and then hunker down during bad weather.

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  4. Thanks Jeff – really interesting and I had been thinking about the exact same thing. I agree that probably they are able to find somewhere to take shelter and I survive.

    But I did have one thought – we probably see a sort of normal distribution of individuals emerging for each species, so we get a few at the early tail end, which would be the ones that start to pop up in January and February, and then it really peaks a few months later, before dropping off after that. Then rather than being adapted overall to survive these kinds of cold events, we might have a range of strategies that do well, depending upon the weather. There could obviously be an advantage to emerging early in a good year because there are flowers that not much else is exploiting, but in a bad year the ‘Beast from the East’ might get you.

    I wondered whether there might be a genetic basis for emergence time? If so, if early emerging individuals are affected by these cold snaps, then we might end up with fewer individuals the following year with those genetics for emerging early. If we looked at long-term weather data and combined it with emergence times and abundances in the early months (e.g. from BWARS), might we see an effect of the previous year’s weather? If yes, this could indicate that these cold snaps do actually kill individuals (…though alternatively may just reduce fitness). It could be another way of testing the hypothesis besides mark-recapture.

    Hopefully that makes sense – just a thought that I wanted to share really. And I am not an evolutionary biologist so this might be incredibly naive, but perhaps you have some thoughts on it.

    Ben

    Liked by 1 person

    • Thanks Ben, some interesting thoughts there. I agree, it’s possible that we might see some patterns from correlating weather and emergence data. Maybe a task for the Pollinator Monitoring Scheme?

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  5. I would have thought that insects that inhabit our shores would have learned a long time ago how to adapt to rapid weather fluctuations. Otherwise, as you say, they just wouldn’t be here.

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  6. Pingback: A once in a lifetime sunset? | Jeff Ollerton's Biodiversity Blog

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