Bees + The Climate Crisis: Pollinator Mismatch (Ep. 16)

Bees are a crucial part of our ecosystem, and their well-being is vital to the survival of many other species. One of the most important things for bees is to have access to food when they wake up from their overwintering stage. They need to forage on flowering plants to gather pollen and nectar to fuel themselves for the early stages of their life cycle.

Today we are talking about new research that found that the temperature in the three months leading up to the bees’ emergence plays a significant role in determining when they will emerge. In a study that looked at data from 1980 to 2019, researchers found that bees tend to appear earlier when the temperature is warmer.

Dr. Chris Wyver works at the Centre for Agri-Environmental Research at the University of Reading in Britain. You can read his complete study here. And if you thrive on data, check out the Bees Wasps & Ants Recording Society website. This is where Chris got the statistics used in his study. 

This is the third in our occasional Bees + The Climate Crisis episodes. You can learn more about how excessive rain harms bees in Episode 3 and how intense heat affects them in Episode 5.

Good to know

Chris talked about the Fruit Watch project, which aims to monitor how fruit trees are changing flowering dates across the UK. Learn more about their work on their website, or get involved if you live in Great Britain. Their Twitter feed is also fun; people chime in on what fruit trees are blooming near them.

Transcript

[00:00:00] How do you feel when you wake up? A bit groggy, maybe grumpy, perhaps hungry? When bees wake up in the spring, you can bet they are hungry and looking to get a nice big meal. But what if the nectar and pollen they need hasn’t started blooming yet? Today we’re going to talk to Dr. Chris Wyver from the University of Reading, who took an exhaustive look at historical bee data.

He found that on average, for every degree Celsius rise in temperature, wild bees are waking up nearly seven days earlier. There’s a lot to discuss from Chris’ findings, but first, why does it matter if bees become early birds? Yeah, so it’s really important when the bees emerge from their… their kind of overwintering stage that they have some breakfast.

The first thing they want to do is, is wake up, [00:01:00] fill up on energy. So they’re going to go foraging for energy. So they’re going to go look for flowering plants that they can get their resources from pollen nectar in order to basically fuel themselves for their early stage of their, their kind of life cycle.

So yeah, it’s really important that the bees, when they wake up, they’ve got something they can forage on. Yeah, really, really important. So tell us how did you conduct this study? Okay, so in the UK or Great Britain, we’ve got this amazing long term recording scheme for bees. So it’s held by the Bees, Wasps and Ants Recording Society, who are an organization kind of responsible for

yeah, unsurprisingly bees, wasps and ants. And they’ve got this, this data set that of observational records of different species of bee, particularly that I’m interested in that goes back well over a hundred years back into, yeah, hundred, hundred and fifty years worth of

data. So what we’ve done is taken [00:02:00] the last sort of forty years of that data. So from 1980 up to 2019 when we first kind of

started looking at this and when my, my PhD project started. So from these records we kind of estimated so kind of the first emergence. Not the very first emergence because some bees wake up extremely early, kind of confused. But we’ve taken the, taken away, the very extreme early emerging bees taken the, where the bulk of the, the bees across Great Britain start to emerge, and we’ve kind of compared that to temperature basically for a three month period before the emergence date, and what we see is that actually in, when that temperature in the three months

before the bees emerge is warmer. We see the emergence date is is earlier generally for many species Um, yeah, and then from that we looked at whether some different life history traits of the bees So we looked at whether they affected how sensitive the emergence [00:03:00] dates were to climate and climate change.

So we’ve looked at things like how many generations each bee has in a year. So some bees will have one, there’ll just be one generation of a particular species in a year. Some species there’ll be more than one, some might have two, some might be, have many generations in a year. So whether that affects sensitivity to climate.

We looked at how specialized their diets are, so whether they forage on more or less anything that flowers or whether they forage on things that have from a restricted range of plants, basically, and a couple of others. So we looked at overwintering stage, whether they overwinter as in a cocoon or as a pre puber and finally, whether they are generally spring emerging species or summer emerging species.

Anyway, so we looked at all these different traits to see whether there was an effective basically life history strategy on sensitivity to climate change. Didn’t find any [00:04:00] strong drivers there, but, um, something that was definitely worth investigating as well. So, yeah, so it’s quite a little bit exploratory. Yeah, no, an interesting study, I think.

Very interesting. Was there something specific that sparked your interest in looking at bee wake up times? Yes, so I, when I first started my PhD back in, 2019 now, I spent some time out in apple orchards, just surveying the bees, seeing what species visited particular varieties of apple, whether there’s a, some species prefer certain varieties or whether it’s just a, the general community that sort of visits everything.

But actually while walking through the orchards, particularly in the early flowering varieties, we’re actually not really seeing much kind of bee activity. So it sort of got me thinking actually, are, what is causing these bees to not be there? Is it just that they don’t, they’re not there anyway, geographically, or the habitat’s not suitable, [00:05:00] or is it actually that they’re there, but they’re just not there at the right time?

So actually that kind of, something sort of went oh, maybe that’s something that is sort of needed to, to investigate, yeah. So what was your biggest takeaway or surprise in the results you found in the data? You looked at so many different life traits and aspects. Um, was there any one thing or any two or three or more things that kind of jumped out at you?

Yeah, so I think the first thing, so we looked at, um, 88 species of bee in Great Britain and I think the first sort of surprise was that actually, although kind of on average, there’s a sort of a six and a half day advance in emergence dates per degree warming, actually the variation between different species was pretty big, so some species we saw actually didn’t seem to be super impacted, so the emergence dates remained pretty constant throughout the last 40 years, whereas some species we’ve seen kind of 20 day per degree increase in [00:06:00] temperature advance.

So actually the, the sort of thing that kind of surprised me was that actually there’s such a wide variety of responses to, to temperature change and climate change generally, but within a group such as these, actually the, the differences. Yeah, it sort of took me a little bit by surprise actually. Yeah, that’s kind of the main takeaway.

So bees need the plant resources, but plants also need bees. Do you have any idea on how this mismatch could affect plant pollination, especially based on your early interest in the apple orchards? Yeah, so I think spending the time in the apple orchards and working with some of the other researchers at Reading who are looking into this sort of thing as well, actually we find that when particularly for things like apple crops, pear crops, fruit crops, which are quite commonly grown in certain regions of the UK.

So they’re quite kind of commercially important, culturally important crops. [00:07:00] Actually we see, if the bees are not there, actually the fruit set you get at the end is very, very small. In comparison to if you have natural bee pollination or you kind of pollinate by hand. So actually you see if the pollination isn’t there, particularly in these crops, so apple crops, many of them need pollen transfer from a different variety to set fruit and the wind is a pretty poor transporter of that cross pollination.

So actually the insects are really important at visiting the different varieties of apple or pear or whatever’s in your orchard, um, to help the main crop set fruit. So kind of actually is super important for not just commercial fruit crops, but also other plants that, um, insect pollination, bee pollination is there to help kind of increase the success of those, those plants.

Yeah. [00:08:00] Are there any other elements of climate change and its effects on bees that you’re especially worried about? Yeah. So with the sort of, uh, the kind of extreme aspect of things, so if these bees are waking up earlier, waking up earlier, yet the climate is getting more extreme, then they can be exposed to things like late frosts, extreme water logging, things like that.

So, actually looking at, although there’s a general trend of emergence on the year to year kind of risk of being caught up in unfavorable conditions increases a little bit as the climate becomes more variable, more extreme. So that’s something that is kind of something we’d quite like to look at as well.

So kind of, yeah, on my list of things to do. So that’s kind of the next sort of bit we’d like to test and see if actually we need to be worried about it. Do you have a favorite bee? [00:09:00] Um, yeah, I suppose I do. I like the, some of the bumblebee species we get here in the UK are really kind of charismatic. I like the red tailed bumblebee.

Big, it’s bold. It’s yeah, it’s very nice to see. How can we support native bees in the face of climate change and other stressors in their lives? Yeah, so I think the kind of takeaway from this study especially is that if things are waking up earlier, bees are waking up earlier from their overwintering period, actually it’s really important that they’ve got the plants that they can fill up on, they can visit for resources, so actually it’s really kind of, I think it’s really important that we plant things in our gardens that

that maybe flower a bit earlier than you usually would, so that there’s something there for the bees when they wake up. Generally good to have kind of a range, if you can, a range of plants that flower at different points throughout the year, so there’s always something for the bees to forage on. So I think that’s the kind of [00:10:00] big, um, takeaway that kind of everyone kind of can help with, I think, is that actually providing flowers throughout the whole spring summer period, rather than just having like a a garden that looks great in the summer, have that whole, yeah, that whole period, um, with some flower for the bees.

I think that’s the that we are kind of trying to promote, yeah. This is just another example of how the climate crisis is having a negative effect on bees, and in turn impacting biodiversity. When bees lose sync with the plants they need for foraging, not only are their lives affected, their offspring are as well.

Bees that aren’t strong and healthy aren’t able to pollinate as well, which affects the fruit and vegetables we enjoy. Thank you for joining us today, and I hope Chris’s research will motivate you to take action in the face of climate change, and of course, help the bees. I appreciate you sharing this episode with [00:11:00] your friends and family or leaving a review.

Go to the beesknees. website to learn more about this episode, as well as Chris’s project, surveying fruit crops in Great Britain. The next episode is coming in just two short weeks. Until then, keep buzzing.