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| All right, it does look like some more people are coming in here, but I’m going to go ahead and get started just because I have some short announcements. Everyone, thank you for joining our last webinar of 2026. I’m Bri Price. I’m the WSU Bee program extension coordinator and we will be hosting and arranging another webinar series for 2027. So, keep an eye out on that on our website bees.wsu.edu or our social media. I’ll be posting about what upcoming events we have next year. So, I just have, like I said, a couple of announcements before I introduce tonight’s speaker. The WSU Honey Bees and Pollinators program is a cornerstone of the College of Agricultural, Human, and Natural Resource Sciences, abbreviated CAHNRS, that is dedicated to fostering resilient ecosystems in Washington and beyond. Our mission intertwines innovative research, community engagement, and education to safeguard pollinators that are pivotal to our food security and environmental health. In partnership with the CAHNRS Resilient Washington Initiative, we’re committed to advancing sustainable practices and pollinator-friendly landscapes and ensuring a flourishing future for agriculture and natural resources. There will be time to answer any questions after the presentation today, so feel free to type your questions into the Q&A box below anytime during the presentation. After the event and before you close your browser, you should be prompted to answer a short five-question education and outreach survey. This helps us understand our impact today. And if you miss it before you close your browser, there will be a follow-up email as well. So, today’s speaker is Riley Reed. Riley is a PhD candidate in our WSU Bee program studying under Dr. Hopkins. His graduate work focused on studying how the availability of food impacts honey bee foraging and how this can be used to improve isolation and pollination during carrot seed pollination. This webinar will cover the research he’s done so far, what’s currently still in progress, and potential future directions for improving our understanding of honey bee foraging behavior and solving these problems that carrot seed growers face. All right, Riley, you can go to share your screen and I’ll hide my video. | Woman wearing glasses with Washington State University Logo in background. |
| There we go. And this one. Okay. Hopefully everyone can see this. yeah, so I’m Riley. I’m going to talk about my research on isolation and nutrition during carrot seed pollination. And you can see one of those carrot seed fields right here. oh. Hopefully hm you make it go to the next slide. Interesting. One moment, technical difficulties. There we go. | Man with light hair and glasses appears on the screen.Picture of a carrot field comes onto screen, Text: “Isolation and Nutrition During Carrot Seed Pollination” |
| So the for the production of hybrid vegetable seed, such as carrot seed, we really rely on pollination by honey bees in order to achieve high yields. there’s other insects that can be used for pollination and different kinds of bees. Flies is a popular one. But on the the scale that we’re growing these vegetable seed fields, really honey bees are the best fit. we’re able to much more easily bring in large numbers of pollinators, keep them on the field for pollination, and then remove them from the field after pollination. | Picture of honey bee on carrot flower. Text: The production of hybrid vegetable seeds rely on pollination by honey bees for high yields. |
| However, somewhat unfortunately, carrot seed pollination production of carrot seed also relies on isolation between these fields in order to achieve high quality of that seed. in order to have really good seed, we need to make sure it’s genetically pure. Make sure that the seed in these fields is produced only by the plants within these fields. We don’t want, you know, other varieties of carrots being grown in nearby fields to crossbreed. If the growers have a contract with a company to produce a specific type of carrot seed, and then the customer that they sell their seed to tries to plant that seed, and it turns out to be this weird mix of all different kinds of carrots, they’re not going to go back to that carrot seed grower again. In order for the farmers producing the carrots from that seed to really make money, they need to know what that seed is going to grow. It needs to be really predictable. Which that predictability comes from the genetic purity of the seed. Which is why we need this isolation between these fields. | Picture of a carrot field comes onto screen. Text: But it also relies on isolation between fields for high quality. |
| Now, the growers do already work towards this, especially here in the in the Columbia Basin of Washington. growers work together to spread out their fields by about 2 miles at a minimum between different varieties of the same crop. So, if you have two growers growing different varieties of carrot seed, they will maintain at least 2 miles between those fields. So, problem solved, right? Unfortunately, not quite. what you can see here in this figure, this green spot in the middle, let’s say that’s your carrot seed field. this black circle around that, that’s that 2-mile isolation distance. That’s how far away that’s how far away the closest other carrot seed field will be. Unfortunately, while bees do fly 2 to 3 miles under more naturalistic conditions, like what you’d find in say nice forest full of diverse wildflowers, these are agricultural fields in a heavily agricultural area that would otherwise be a desert. So, there’s not a lot of diversity. it’s not really a great place for bees at the time of year when these fields are blooming. Under conditions like these, where the landscape is far patchier in terms of forage, where those different patches of forage are much more spread out, such as between these different fields, bees have been shown to fly more like six or more miles. you can see that that red circle there. That’s quite a bit further than the isolation distance that we’re currently using for these honeybees. So, while this isolation distance can contain a lot of the foragers, maybe even the majority of the foragers, we are still going to have potential for those bees to be leaving this isolation distance and visiting any of these other fields here within this red circle. And then therefore also the potential for them to bring those the pollen from those fields back to the field they were placed on and potentially reduce the genetic purity of the seed coming from that field. | Satellite map of fields with large red circle overlayed, a black circle is inside red circle, and small green circle is inside red circle. Text: Growers already spread out their fields by 2 miles but its not enough. |
| Now, I do just want to put into perspective that, you know, obviously this is a problem. It’s a problem for growers. It’s not a good situation, but it is really impressive. To put it into perspective, if you account for just how itty-bitty one of these bees is, it’d be roughly the equivalent of if I started out up here in Yakima, Washington and just decided, “You know what? I’m going to walk to Las Vegas and back for groceries.” That’s a long ways. That’s really impressive that they can do that. That they can travel that far. That they can go that far without getting lost. I think I’d make it to maybe here and then I’d be just hopelessly lost in the woods somewhere. But the bees are able to do this day in and day out. So, it is it’s really impressive even if it is kind of a problem. | Map of the continental united states with black line connecting Washington to Nevada. |
| Now, to make matters worse, not only is the landscape around these fields not great for bees, the fields themselves don’t necessarily present great conditions for the bees. When you look at a carrot seed field, especially these hybrid carrot seed fields, you can see these alternating rows such as this one here labeled A versus this one here labeled B. Now, within these, what we have is all these wider, a little bit greener rows. They’re like this one labeled A. That is male sterile plants. So, those plants only produce nectar. There are no male parts on those plants. So, it’s just nectar, no pollen. That is the parts that they harvest for seed. Whereas the ones like this one labeled B are the complete flowers. So, they have both male and female parts. They produce nectar and pollen. And that is where the bees are able to gather pollen on these fields. Now, the reason the growers plant them like this is that this way they know that all of these A rows are pollinated specifically by pollen from the B rows, you know, barring anything the bees are bringing in from other fields. then they can go through and harvest all the A rows and know who both parents are. They’ll know that the parents are the mother is from this line that they planted in the A rows, and then the pollen or the father is from these B rows. So, you know exactly what these seeds are a hybrid of. They can produce exactly the kind of seed that they want. And then at the end they’ll just mow down the B rows and not harvest them because that seed is a little bit less predictable. It’s not the same hybrids they’re trying to grow. But from the bees’ point of things, this means that only a small portion of this field, about a quarter to a third, even produces any pollen whatsoever. The whole field will produce nectar, but only a small portion will produce that pollen, just these B rows. So, you’ve got a very large number of bees on these fields in order to have enough bees to perform the pollination, yet not a lot of resources for them to gather. Helping force them to fly farther in search of alternative forage in order to meet their needs. | Picture of rows of carrot seeds, 2 sets of black parallel lines appear labeled A or B. Text: Poor conditions of a hybrid seed field forces bees to search for alternative forage. |
| As if that wasn’t bad enough, then only are the carrots not carrot fields not necessarily providing enough food, some varieties of carrots actively repel honeybees based on the scents they give off. you can see here there is some scents like this beta-ocimene that some of these carrot flowers will release that do attract bees. There’s also plenty of these other ones like this sabinene, beta-selinene, and alpha-selinene that actively repel bees and reduce their foraging on these plants. now some of this may maybe this originated in, you know, the ancestor of carrots. There’s also potential that through the breeding efforts over the years, you know, normally attractiveness to pollinators isn’t really something that we breed crops for. We breed them for things like how they taste or how they produce or how easy they are to harvest. Normally attractiveness to pollinators is isn’t necessarily something we’re considering. Usually it still turns out fine. but in cases like this, potentially that creates some problems. So the bees are being placed on these fields in high numbers with poor landscape surrounding the fields, not the best conditions within the fields, and flowers that are actively repelling them potentially, depending on the specific varieties of carrots. These scents do vary wildly between different varieties, making it even harder to predict how the bees will react to these fields. | Graphic of carrot seed flowers labeled with different organic chemicals labeled red as deterrents, or green as attractants. Text: Some carrot varieties produce honey bee repellant compounds in their flowers. |
| Now, there are kind of similar issues faced in some other crops, such as kiwis in New Zealand. Now, with the kiwis, the growers weren’t worried about isolation. They weren’t worried about bees bringing in pollen from outside of the kiwi or orchards and like cross-pollinating their plants with those. That’s not a concern. They’re just growing these for fruit, not for seed. So that’s not a problem. But they did have problems with the bees not liking the kiwis so much and going to other types of flowers to pollinate instead, leaving the kiwis not as pollinated as they should be, so their yields weren’t as good. | Picture of a kiwi. Text: Kiwi growers in New Zealand also struggle to keep bees on their crop. |
| So, to try to get around that, they were looking at how can they encourage bees to stay in those kiwi orchards better and pollinate them better. well, they started off, they tried feeding them sugar syrup, and what they found was that that didn’t really impact the amount of non-kiwi pollen being collected. The bees would still collect as much pollen from all the other plants as they normally did, but they would also collect more pollen from the kiwis. So, they’re spending more time foraging on those kiwis, but also the same amount of time foraging on the non-kiwis, likely just resulting in more foraging overall, but primarily on the kiwi side of things, once they had those nectar or sugar syrup needs being met, encouraging them to spend more time foraging for pollen. | Bar graph showing number of pollen pellets over time from Goodwin 1986. Text: Feeding sugar syrup increase the collection of kiwi pollen. |
| They also tried looking at kind of the other side. You know, bees, when they’re foraging, they need I mean, a few different things, but primarily they need pollen and nectar, along with small amounts of things like water, propolis, stuff like that. But they tried feeding them pollen supplements or protein supplements as another option to see okay, this we know what the sugar syrup did, what will the pollen supplements do? And when they tried that, what they found was kind of the opposite in a way. The amount of kiwi pollen being collected didn’t change. The bees were collecting the same amount of pollen from the kiwis whether they were being fed or not fed. However, they did collect significantly less non-kiwi pollen. So, it seemed like maybe pollen foraging overall went down, but the that primarily came out of the amount of non-kiwi pollen they were collecting. So, they were staying on the kiwi better even if the kiwi wasn’t necessarily being pollinated better. | Line graphs showing number of pollen pellets over time from Goodwin 1986. Text: Feeding pollen substitute decreased the collection of other pollen from other plants. |
| Based on those results, we hypothesized if we combine the two, providing the bees with both sugar syrup and pollen supplements or protein supplements, we could better meet the nutritional needs and cause them to forage more on carrots and less on the non-carrots and other things outside of these carrot fields in order to keep them on the carrot fields better. | Rectangular pollen patty laying on top of honey bee hive frames. Text: Providing sugar syrup and pollen patties will remove their need to forage at longer distances. |
| So, we did an initial kind of smaller test study with this where each colony was fed a gallon of sugar syrup each week as well as provided with pollen patties each week which were replaced as needed. | Rectangular pollen patty laying on top of honey bee hive frames. Picture of a large vat of sugar syrup. Text: Colonies were fed sugar syrup and pollen substitute each week during carrot pollination. |
| We then went through and trapped pollen coming into the hives to kind of track where exactly the bees are going or at least what exactly they’re foraging on. | Three honey bee hives next to each other, the middle hive has a pollen trap affixed to entrance. Text: Pollen traps were used to collect pollen from foraging honey bees. |
| And the results turned out to be definitely not what we thought, still pretty interesting. These treatments did not impact the foraging in the way that we expected. There was no real difference in the diversity of pollen being brought back whether they were fed or unfed. And we started these feedings right at the beginning of carrot seed. So, the bees were placed on the field and we started feeding then and then continued throughout the carrot seed pollination. But what we did find interesting was that only a little over 10% on average seemed to be coming from the carrot seed, whereas they were bringing far more corn pollen than carrot pollen. So, it seemed like there was quite a bit of quite a few bees leaving these fields and fortunately something which we don’t normally think of bees as visiting. which we found pretty interesting. And so, even though we didn’t get the results we expected, we decided this study was worth you know, let’s continue looking into this. | Bar graph showing mean percentage of pollen in fed or unfed colonies with pollen source (carrot, corn, or other). Text: Feeding during carrot pollination did not significantly impact pollen diversity. |
| What we ended up finding in the next year, repeated the study with more hives. We also added in some additional types of data. | Satellite picture of carrot seed field with honey bee colonies. Text: Summer 2024 |
| Most importantly, we decided to go with kind of the MythBusters approach. You know, on MythBusters back in the day, if they tried to test a myth and they found that it was false, it didn’t actually work, they’d keep trying and trying and doing it harder and harder until it worked, even if they had to go to kind of outrageous lengths to do so. So, this year, instead of beginning feeding right when we place the bees on pollination and you know, they only get fed for 3 to 5 weeks during that pollination, we started feeding all the way back during almond pollination, giving them months and months of being fed sugar syrup or being fed pollen patties, rather. Due to concerns about them building up too many honey stores, we didn’t start sugar syrup feeding until carrot pollination again. But we at least started feeding those protein supplements far earlier in the year, all the way back in like February. | Picture of the hosts of Mythbusters. Text: In 2024, feeding began during almond pollination. |
| We again placed these pollen traps on the hives and additionally placed these brood minder bee dars, which use Doppler radar to track activity around the entrance to give you an idea of kind of how much overall foraging activity is going on within these hives. | Picture of bees coming in and out of a plastic pollen trap, and a white and green (broodminder) box affixed to honey bee hive. |
| We found was the feeding still didn’t really have any impact when we looked at foraging activity over the course of the study. it’s kind of hard to see because it’s broken up over so many different time points, but overall, there just wasn’t really any significant difference. You can see some days maybe the fed seemed to forge a little more, but it wasn’t anything significant. | Chart showing foraging activity over time across 26 days, with unfed and fed treatment groups. Text: Feeding had no significant impact on activity. |
| When we looked at the average mass of pollen being collected, so how much total pollen they were bringing in, not just how much diversity of pollen. We found that again, they seem to be bringing in about the same amount regardless of being fed. and then we also found that they were bringing in about the same kinds of pollen seemed to primarily again be less carrot than anything else, a little bit more than the previous year. They were bringing about 20% carrot pollen. but what was interesting about this was again what was in that other pollen. | Bar graph showing pollen trapped (grams) in unfed and fed treatment group. Text: Feeding had no significant effect on the amount of pollen collected by colonies. |
| What we found was that it seemed to be primarily asparagus pollen. Now, this was interesting because unlike corn, which is grown everywhere in this area, so we have no real idea where exactly they were gathering that corn pollen from, asparagus fields are much more rare. | Microscopic picture of pollen grains. Text: Asparagus was one of the most commonly found pollens. |
| So, when we look at a map, we can find out, you know, this is where the carrot seed field. The next closest asparagus field was all the way over here. There was a few more even further away. like one, I think this was the next one. but you can see even this closest asparagus field was about 2 and 1/2 miles away. So, that means the majority of the pollen they were bringing back was still coming from outside that 2-mile isolation distance, showing that a lot of these bees are breaking isolation and leaving that 2-mile range. so, we still hadn’t really found a solution to the problem, but we did now kind of prove that there is indeed a problem. Before this, we were largely going off of kind of some assumptions and stuff we’d heard from growers and stuff like that, more anecdotal evidence, but now we could really help prove to things like donors that we really do have a problem we need to work on. | Satellite map of cropping systems, with white arrow pointing to asparagus field. |
| This also, on kind of beekeeper side of things, one thing we’ve heard anecdotally from a few different beekeepers is concerns that feeding bees makes them lazy. If you’re giving them lots of food, they’re not going to leave the hives as much. We’ve also heard that from growers who worried if beekeepers are feeding their hives that the bees wouldn’t be pollinating as well. And so, while we didn’t solve the problem, we were out to solve, we did find that clearly that’s not the case. You can feed the bees and they’re still going to go forage. based on some of those other studies we’d looked at, potentially they’ll forage more, potentially pollinate even better, or they’ll forage about the same, as shown by our results. we also later got to thinking, well, in kiwis, they did each type of feeding separate, the sugar syrup and the pollen patties. There is potential that by feeding both, they essentially canceled each other out. When you feed the bees just sugar syrup, you’re encouraging them to forage more for pollen by meeting their nectar needs. When you feed them protein supplement, you’re meeting their protein needs more, encouraging them to forage for more for nectar. By feeding both, we kind of met both their needs, so the foraging could go on kind of the same as it would without either of them. | Cartoon graphic of three honey bees leaning back in recliner chairs labeled “lazy bee”. Text: These results show that concerns about lazy fed bees are unwarranted. |
| But, still there is this problem that we need to continue working on solving. So, in 2025, we decided to try to take kind of a different approach to this. | Satellite picture of carrot seed field with honey bee colonies. Text: Summer 2024 |
| you see, when you look within the hives, what’s happening when the bees come back from foraging, there are quite a few different behaviors happening and allow the colony to regulate what kind of foraging they’re doing based on the needs of the colony and what kind of food stores they have. with pollen, this can get a little complex because pollen provides a lot of different nutrients to the bees, and it’s not always the best understood how exactly they’re regulating that. But, nectar is much simpler. They just need basically as much honey as they can get to try to build up for winter. it’s really just based off the amount of space the honey is taking up. So, what happens is you have in a hive with lots of empty space, it means a lot of nectar, these foragers are coming in, they find a receiver bee, who will or a storer bee, who will then take that nectar from the forager and go find some place to put it. So, if there’s lots of empty space, very quickly that receiver bee will find an empty cell and deposit that load of nectar, and then return to the entrance to collect the next load from the next forager. This very quick turnaround helps signal to the foragers that there’s lots of space and they should continue foraging for pollen or for nectar, rather. | Animated graphic of bees moving around yellow hexagons. Text: Colonies with large amounts of space forage at a higher rate. |
| However, if you have a hive that’s very full, they’ve got lots of honey, they don’t need a lot more. What happens instead is when the bees return from foraging, they pass up that load to the receiver bee. It takes the receiver bee much longer to find some place to deposit that load. Meaning that the foragers have to wait and wait and wait. And it’s you know, essentially creating kind of a line as they wait to unload. And this signals to the foragers, we have plenty of nectar, we can you know, kind of dial back on the amount of nectar foraging we’re doing because we’re running out of space anyways. | Animated graphic of bees moving around hexagons, this time most are orange with a few that are yellow. Text: Colonies with little space decrease foraging. |
| So, based on these kinds of feedback loops, you can see, to put it into more human terms, you know, if you get home and you’ve got a fridge that looks like this, you’ve got a fair amount of food, maybe you don’t have exactly what you want, maybe you’ll make a quick trip to like the corner store or something, but you’re not going to do like a big grocery run. If you got an empty fridge, you’re going to need to go buy groceries or something. and if you have lots of food, you’re not going to the store at all. That’s kind of how the bees would determine whether or not to do more foraging. If they have a little bit of food, they’re going to do some foraging. If they have no food, they’re going to it’s all hands on deck, they’ve got to forage as much as they can. And if they’re completely full, they can really scale back the amount of foraging they’re doing. | Picture of empty fridge next to a full fridge. Text: Honey bee foraging behavior is influenced by food stores within the hive. |
| now, this has also been shown with some other studies, such as this one, where they found that if the bees were provided with pollen patties, their foraging on cantaloupe wasn’t really changed. And the pollination in the cantaloupe wasn’t really changed. so, as you can see, the amount of pollen being deposited on these flowers with the control groups that were unfed and the ones where they were fed pollen patties really stayed the same. Where they really started to split off was when they gave them frames of pollen, which could better signal to the bees that they have lots of pollen, they don’t need to forage for pollen as much. So, they could forage more on these nectar providing cantaloupe flowers. So, based on that, it seems like maybe going and directly manipulating the frames of food is a more effective way to alter honeybee foraging behavior compared to just offering these you know, sugar syrup and pollen patties that the bees can then choose whether or not to collect. So, we kind of decided to force them to have more food rather than giving them the option of having more food. | Three line graphs showing number of pollen foragers per 200 flowers, percent of pollen foragers, and number of pollen grains per stigma, per number of days after colony treatment (Chabert et al. 2023) Text: Feeding pollen patties did not significantly alter foraging in cantaloupe. |
| So, our hypothesis with this was that colonies with less open space will forage at a lower rate. They’ve got plenty of food, so they don’t need to forage as much, but they’ll also remain closer to the hive. Basically, the idea being they’ve got plenty of food, they don’t need to forage as much, and they don’t need to fly as far. They can just go for the easy pickings that is the carrot seed field that’s right next to the hive even if it’s not the best forage. | Picture of beekeeper standing next to hive that has several honey boxes stacked on top. Text: Hypothesis – colonies with less open space will forage at a lower rate and remain closer to the hive. |
| So, to test this hypothesis, we took hives where we had equalized the amount of bees and brood within the hive so that they’d have the same amount of foragers roughly and roughly the same amount of brood and then for the same demand for food between each hive. and then we created hives that had different amounts of pollen, honey, or nectar, and empty comb ranging from hungry or starving hives where we removed essentially every bit of food we could. There was little bits around some of the brood that we couldn’t really get out of the hive, but everything else we took out. we had hives that were completely packed with food, as much food as we could fit in there. We were going through making extra frames of pollen, filling in gaps on partially filled frames with sugar syrup that we sprayed directly into the frames or packing it by hand with additional pollen to fill it in better. hives that were similarly full, but then we placed an empty super on top as kind of a more easy way for beekeepers to perform these manipulations themselves that they just took plugged out hives and threw an empty super on top rather than going through and directly manipulating the frames beneath. And then also hives that were kind of in the middle. They had a good mix of empty comb, of pollen, and of honey. Kind of more of like what you’d expect to see in a hive on average for that time of year. That’s kind of our control group. | Honey bee frames with capped brood, pollen, or honey. Text: Colonies were given large amounts of empty comb, pollen, and honey. |
| We then went through and again used those broodminder bee counters to track entrance activity, used pollen traps to try to identify the amounts and types of pollen being brought in between treatment groups. And then this year, well we tried this previous years we met various roadblocks. This year we were successfully able to also use these observation hives, which allow us to record what’s going on inside of these smaller hives, which have the same conditions of being full or empty in terms of food stores, and record the waggle dances going on within those hives to try to track where exactly the bees are foraging. | Picture of honey bee colony inside a long vertical glass box, and picture of bees coming in and out of a plastic pollen trap with and a white and green (broodminder) box affixed to honey bee hive. Text: Pollen traps, activity monitors, and observation hives were used to track behavior. |
| Now if anyone’s not familiar with the waggle dances, this is one of the ways the bees communicate to their nestmates where to go find forage, where they’re finding this honey and nectar that they’re bringing back. It’s also used in swarms to try to communicate where potential new nest sites are. And basically, the bees are going on a figure eight pattern on the comb. This is all in the dark which makes this even more impressive they’re able to do this. And the middle of that figure eight portion, like you can see right there, is communicating the distance and direction to the food. So if it is going directly up on the comb, directly against gravity, that means the food is directly towards the sun. If it’s going directly down on the comb, that means it is directly away from the sun. If it’s going at like a 45° angle like this, although in real life it’d be the bee changing the angle, not this entire comb, then that means it’s about a 45° angle off of the sun. So in this case the middle portion is also telling the distance based on how long that waggle lasts. So in order to decode these, we record them on some nice camcorders that allow us to then go back through on that footage and slow it down and really measure the exact angle and the exact duration of these dances to try to map out where the bees are going. Which is far easier than when they first discovered this dance and had to do this all by hand while the bees were actively dancing, which is far more impressive. But this allows us to really track exactly where the bees are at least recruiting to. And bees will only dance for good forage sources. So if they’re dancing for those, this is a spot where they’re likely going to be doing more and more foraging because it’s a good source of either nectar or pollen. | Animated graphic with a bee dancing in the middle of a group of other bees watching the dancing bee. Text: Waggle dance is used to communicate the location and quality of a resource. |
| What we ended up finding from this attempt or from this hypothesis, again, the amount of pollen collected by treatment groups was not significantly impacted. So, regardless of whether they were full of food, full of food with that empty super, completely starving, or had a moderate amount of food and empty comb, they were bringing in about the same amount of pollen. | Bar graph with average mass of pollen with full, full+super, hungry, or medium treatment groups. Text: None of the treatments significantly impacted pollen collection. |
| Technically, the amount of foraging trips was slightly impacted with those, colonies full of food having a little bit more foraging activity, but while it was statistically significant, it wasn’t really significant biologically, economically, anything like that. This tiny little difference, isn’t really going to have any real world impacts. Interestingly, by the end of the study, which actually had to end a week early, due to the bees, regardless of whether they were full or starving, managing to find enough food to start to plug out the hives, kind of removing our treatment groups themselves. So, they are clearly at least able to recover from even those starving conditions, even on these fields where it’s not the best conditions, they’re able to go out into the environment and find something to fill up on, which is particularly interesting if you refer back to, this slide where they were bringing in the same amount of pollen, yet ended up being, ending up with the same amount of pollen and bringing in the same amount of pollen despite starting with different amounts of pollen. | Bar graph with foraging trips per day with full, full+super, hungry, or medium treatment groups. Text: Overall foraging activity was only weakly impacted by our manipulations. |
| What was more interesting was looking at that waggle dance data, where we found that, there was some significant difference between treatment groups. And here you can see kind of all the treatment groups mixed together, so you can kind of start to see some trends showing up like these medium ones seem to be foraging outside of this isolation distance quite a, but it’s much easier to see when we break it down by treatment group. | Satellite image of cropping field, with black circle around 2 mile radius from center, small icons indicate foraging distance in full, full+super, hungry or medium treatment groups. Text: Recruitment distance was significantly reduced in hives with very little food. |
| All right, to be clear, this is all still the same field , just like on the previous slide. I’ve just made four copies of the same map , and only show one treatment group per map. This is not four separate fields. I know this has caused some confusion in past presentations. But what we can see is that these medium hives, do forage significantly further , on average from the field than the other treatment groups. They seem to fly quite a ways away. You can see just how many are leaving this this black circle, which is that 2-mi isolation distance. And then while they’re not significantly different, the full plus super are also significantly different. They forage the closest to the field, kind of going against everything we suspected with the full and the starving falling in the middle. So, these two, the full and hungry ones, which should have been the extremes based on our hypothesis, actually fall kind of in the middle. While these two hives that should have been we expected to be foraging more moderate distances, these , medium or average hives, and these ones that were full of food with some extra empty space, making them kind of similar to the average hives because they have lots of food and lots of space, forged the furthest and the closest. , we’re still not 100% sure why this is. We have also repeated this study, this year. | Four satellite images of cropping field, with black circle around 2 mile radius from center, each image showing small icons for only 1 treatment group (full, full+super, hungry or medium). Text: Recruitment distance was significantly reduced in hives with very little food. |
| But we’re still working through that data. This is showing also that over time, during this this previous study, that it changed how far they were going , each week over the course of this this 3-week study. So you can see for example, like the medium hives started out flying much further away. And for some reason in week two, they were staying a little bit closer and then went back to flying further away. While the full plus super ones seemed to do the opposite. They started out , closer, and then suddenly were flying further and then came back. So we we’re still decoding more dances based on kind of how unexpected these results are, we decided to increase how many dances from the videos we would decode to see if maybe this is data is being thrown off by outliers. we’re decoding more trying to get a a better overall picture of what exactly is going on during foraging. So we are still working through decoding more of those dances, which will hopefully yeah, improve our understanding and then we’ll be able to share those hopefully better understanding with all of you down the road. | Line graph showing mean recruitment distance over three weeks with full, full+super, hungry, or medium treatment groups. Text: Recruitment distance also changed over time. |
| Since these results were somewhat promising but also really unexpected, we decided also it’d be worth repeating the study. You know, let’s see maybe the reason for that was just the that it was a fluke, maybe that pattern holds consistent year to year. so we repeated the study this year but we have not really had time to start decoding those dances and we’ve only just started working through the pollen samples at the moment. so we are not able to unfortunately to talk really about what we found so far for repeating that study. hopefully more to come sometime later this winter or next spring. but you can see here a kind of a a better picture as well of how exactly these waggle dances work. we have these camcorders which are inside of this shed. this is just like one of the sheds you’ll see at like Home Depot that they just sell like out in the parking lot. we place it on a trailer so we can haul all of these observation hives a dozen of them in total to the fields and then we’re able to use these camcorders to record the frames that’s in these hives and watch all of these waggle dances the bees are doing to really get a good idea of where exactly they’re going. | Inside of a shed with 11 honey bee colonies housed inside narrow glass vertical boxes, with cameras pointing at hives. Text: More research is needed to fully understand these differences. |
| There has also been other studies outside of my own work on kind of similar problems in some of these other crops like what I was talking about with the kiwis. so there are some potential other solutions as well that really deserve more study in carrot seed such as this one from I believe this was in pears, where they found that combining these, they did both pollen traps and sugar syrup, so giving the bees additional sugar syrup and also depriving them of the pollen they could collect to really exacerbate their need to go forage more for pollen while meeting their needs for nectar through the sugar syrup. and they found that combining those two really helps encourage the bees to forage on some of these plants like pears that provide lots of pollen but not a lot of nectar. , so potentially that’s something worth looking into in carrots as well. | Bar graph of mean number of bees entering with pollen in four treatment groups from Gemenda et al. 2018. Text: Combining pollen traps with sugar syrup increase foraging on some plants. |
| Additionally, in some crops, other researchers, and there’s even been a couple companies have had success with essentially tricking the bees into thinking the crop is better than it actually is. You know, bees forage, in a large sense off of the scent of the flowers. It helps them find the flowers over and over, because that scent can carry a long distance. It helps them identify the flowers as well. So, if you provide the bees with scented sugar syrup, or provide them with sugar syrup while also providing the scents, you can kind of trick them into thinking that all that sugar syrup you’re giving them came from those flowers. Like in this case, this would be, sunflower scented sugar syrup. This can then train the bees to go look for those sunflowers more, and then they’ll come back and dance once they found them and recruit more bees to go look for sunflowers, even if the sunflowers aren’t actually providing as much nectar or pollen as the bees expect them to. You’ve essentially trained them to kind of overcome that, which is another thing that really needs to be looked into more in carrots. Now, in carrots and plenty of other crops, this does kind of go back to that issue with the volatiles I was talking about earlier where, you know, some of these carrot varieties are producing scents that actively repel bees, but also between all the different varieties of carrots, there’s vast differences in how they’re going to smell to the bees. So, finding one scent you can mix into the sugar syrup that will be close enough to the scent of all the carrots will take a lot of research, but hopefully someday, someone else will be working on that as well. | Circular diagram showing how olfactory conditioning and social learning in bumble bees could improve crop pollination. Bees learn a mimic floral odor paired with scented food, develop a specific odor memory, show enhanced foraging and biased floral preferences, and visit target floral VOCs, potentially increasing crop yield. Text: Scented sugar syrup can be used to train bee to specific crops. |
| That pretty much sums up my research so far. Like I said, we’re still working our way through some more of it. So, hopefully we’ll be able to publish some some average publications and such down the line as we wrap that up. I just wanted to share these results with you so far. Kind of give you an idea of some of the exciting research going on at WSU. I like to finish up by thanking my committee, Dr. Hopkins, Dr. Shepherd, and Dr. Felsot, who helped me with this research as well as all of our various funders and collaborators such as the Columbia Basin Seed Association, USDA-NIFA, Western SARE, everyone else in the bee lab who’s really helped me with all this, and Bejo Seeds who lets me play in their carrot seed fields every year. | Acknowledgements with pictures of collaborating researchers and logos for funding sources. |
| Here are some of the references. If you’d like to refer to these later, here’s some more. I would kind of like to second what Bri said earlier about please fill out this this outreach survey. It really helps us track, you know, how our how our outreach is reaching all of you, how it’s helping you, all that kind of stuff. any questions? | List of references cited during presentation, then quick advance to a screenshot of outreach survey questions, and an ending slide that says “Questions?” |
| Bri: Thank you, Riley. How interesting. I think this is the first time I’ve heard all about what you do because I know kind of what you do, but this was very cool talk. Yeah, if anyone has any questions, go ahead and type it into the Q&A box down below. We’ll just patiently wait here for about a minute or two, and if there’s no questions, then that’s okay, too. [pause] Bri: I have a question in the meantime while waiting on anyone else to ask is are you using any sort of like artificial intelligence for the waggle dance decoding or is it all manual? Riley: I would really love to use some sort of computer program to do it. but it seems like so far results with using those there’s been some promising results but it sounds like it still has a long way to come to really be like super accurate and super good at detecting these dances. my footing or my footage also makes it a little bit more difficult because a lot of studies that do things like this are doing them in a lab where they can really tightly control like lighting and everything like that. With mine we’re having to go out to the field, you know, 100 miles or better from the lab and use this little shed powered by a generator to try to record it. So the footage isn’t is good enough for a human to recognize the waggle dances but isn’t necessarily good enough for like AI or anything to do it quite as well. There’s a lot going on on a frame so it’s really hard for AI to track each individual bee. so at the moment it’s all being done by hand by by me and a couple undergrads. but hopefully someday we’ll be able to use some some AI to do this. I know there’s been a few different researchers working on that. Right now it’s part of why a lot of this is still preliminary is that it takes forever. Bri: Awesome. Okay, that’s a great answer. we do have one question from the audience. are there any other better pollinators for carrots like native bees or any other sort of managed bee? Riley: So it depends on how you define “better”. For a lot of like when they’re doing smaller amounts of carrot seed like when they’re growing them in greenhouses or in like covered areas where they’re doing more like the smaller production plots to make seed to then plant in these big fields. They do a lot of fly pollination because flies are much more attracted to the carrots it seems. They really like the carrots, especially , drone flies. , Eristalis tenax, I believe is the Latin name. But those ones work really well as well as a few other species of flies. , the issue is that when you deal with these larger fields, if you put honey bees on the field, you run the risk of some of them leaving the field and then coming back and hurting isolation. if you dump all the flies on the field, they also can potentially leave the field, but they don’t then ever come back. , so keeping enough flies on these larger fields to get adequate pollination when pollination lasts weeks or the longest I’ve seen was like 5 weeks, during which the carrots are still blooming. It’s really hard to keep the flies on the field that long. So for these larger fields currently, honey bees seem to be the easiest. Off the top of my head, I can’t think of a lot of research on other types of bees. It seems like normally when they’re looking at alternative pollinators, they’re going more towards flies for carrots. just because carrots seem to attract the flies a lot better. Okay. my favorite idea I’ve heard suggested was, some of the flies that feed on like road kill and other carrion seem to pollinate them well. So maybe they could leave some road kill on the edges of the field to draw them in, but then that makes it harder to market products. Interesting. Bri: Yeah, that’s kind of Yeah, would be a hard sell, I bet. Yeah. At least the seed isn’t being eaten, so you got that going for you, but still…All right. It looks like there’s no other questions coming into the Q&A box. So, as a reminder, this is our last webinar of this year. We will be hosting another one next year. All the webinars that we do for our, WSU Bee program webinar series are posted on our YouTube channel which is at WSU Bee program. And as a reminder please do that survey. So I’m going to close the webinar out and then your browser should pop up with those five questions. And if you have any follow-up questions I will be sending the recorded link to all the registrants and I will copy Riley’s email so you’re welcome to email Riley any follow-up questions. So thank you again for attending and I’m going to close out the webinar now. Thank you Riley. Riley: Thank you. Have a nice night everyone. | An ending slide that says “Questions?” |