Pollinator Confidential
Founders of the Feast
In this special holiday edition, Lisa and Pam explore the untold stories of the true ‘founders of the feast’--the pollinators who make our festive table possible. Dr. Margarita Lopez-Uribe shares her expertise on a very important specialist bee, and cranberries and dairy products get a look-in as well. So if you’d like some fascinating, non-controversial conversation starters for your holiday gathering, tune in!
Resources:
http://www.snetsingerbutterflygarden.org/activities.html
https://lopezuribelab.com/squash-bee-biology/
In this special holiday edition, Lisa and Pam explore the untold stories of the true ‘founders of the feast’--the pollinators who make our festive table possible. Dr. Margarita Lopez-Uribe shares her expertise on a very important specialist bee, and cranberries and dairy products get a look-in as well. So if you’d like some fascinating, non-controversial conversation starters for your holiday gathering, tune in!
Resources:
http://www.snetsingerbutterflygarden.org/activities.html
https://lopezuribelab.com/squash-bee-biology/
Hello everyone and welcome to Pollinator Confidential, a podcast featuring the untold stories of native plants and the pollinators who love them.
Pam:I'm Lisa Schneider and I'm Pam Ford, and we are Penn State Extension Master Gardeners from the Snetsinger Butterfly Garden Habitat Project, located in Tootick Park in State College PA.
Lisa:Well, Pam, it's getting to be that time of year. The holidays are just around the corner and, if you're like us listeners, thanksgiving is about one thing.
Pam:Food, Well food and family of course.
Lisa:So today we're going to take a closer look at the true founders of the feast Pollinators, because without pollinators, our traditional Thanksgiving table wouldn't look the same at all. Now you might have heard a statistic that's often given that up to one-third of our diet relies on pollinators, and let's review quickly why that is so. In order for flowers and fruits to form on plants, something has to move their pollen from the anthers of one flower to the stigma of another, and that's what causes fertilization to take place. And in most cases, that something is an insect, a butterfly, moth, wasp, fly, beetle or, in many cases, a bee. Bees are by far the most efficient pollinator, for a couple of reasons.
Pam:They sure are, and for one thing they're built for it. Bees have special hairs and pollen collecting areas to help them transport that pollen. They can groom pollen from their bodies into these areas, which are sometimes on their legs, sometimes on their abdomen, so they can trap and transport more pollen than any other type of pollinator, and they're very motivated to do so. Bees actively collect and transport pollen. They are looking for food and they have found that pollen and nectar to be excellent foods for themselves and for their young. Bees also forage around their nest. So if nesting sites and plantings are provided to encourage native bees, bees will search for food nearby and that will help ensure the flowers are pollinated. All these factors make bees real pollinating superstars.
Lisa:So we thought that today we'd take a look at some of our favorite traditional Thanksgiving foods and the untold stories about the pollinators that help them get to our plates. For example, pumpkin pie. Do you guys do pumpkin pie at Thanksgiving?
Pam:Oh, my gosh, we sure do Thanksgiving, and also the next day's breakfast, sometimes, if there's any leftovers. I remember the time, however, when Doug put salt in the pumpkin pie instead of sugar. Oh oh yeah, it was bad. Well savory, definitely savory. But we also have roasted butternut squash or delicata squash. Yeah, we like all the squashes.
Lisa:Yeah, well, it might surprise you to learn, I mean, I was certainly surprised when I first learned that there's a bee for that, a special bee, the squash bee. And to help us learn all about the squash bee, we are so pleased to be joined by Dr Margarita Lopez-Uribe from the Department of Entomology at Penn State. Margarita, thank you so much for joining us today. Thank you for the invitation. It's a pleasure to be here. So, as I said, Margarita, I think most people are unaware of the existence of the squash bee. And you know, even though I know about it. So I'm out in my garden I grow a lot of cucumbers every year and I'm out in my garden and I'm looking in the flowers and I'm thinking, oh, I think, is that it? Is it a squash bee or what? So how do we? Let's do a little squash bee 101. Okay, just the basics to start with, because they do look a lot like honeybees.
Dr. Lopez-Uribe:A little bit. Yeah, they do. They are about the same size, I guess. What are the differences? So the first thing and I'm going to use some technical words, but I will, you know, try to explain what those mean. So honeybees are what we call corbiculate bees, which means that they have a corbicula, which is a basket on their hind legs, right. So this is why when we, when we see honeybees on flowers and we see them gathering pollen, we see these pollen balls on their legs, right, they collect in their baskets.
Dr. Lopez-Uribe:Bumblebees are corbiculate bees too. Squash bees are closely related to honey bees, but they don't have a corbicula. So the females have a structure called a scopa, which means that they have these really long hairs where the bees, you know like, basically put the pollen to transfer that back to the nest. So for my eyes, that's something that I immediately can tell. Right like, does it have these hairy legs or does it have, you know like, flat hairless, you know like legs, I think.
Dr. Lopez-Uribe:The other, the other difference is the squash bees are the thorax of the squash bees is a little bit hairier than than honey bees, and the males of a squash bees are very abundant in flowers, unlike honey bees, right, like we rarely see drones visiting flowers or if ever, I guess Male squash bees are super important pollinators and they have this really cute yellow spot on their clipeus under, you know, above, their mouth parts. So yeah, so those are some of the differences that I think I use to differentiate them. They also fly in a very different way. So, yeah, if you are passionate about you know like, learning about these squash bees, just try to you know like see them on the flowers, as squash bees are very fast flyers. Honey bees are a little bit slower, so just from the behavior you know like, I also think you can tell them apart.
Lisa:That's very helpful When I see a bunch of a bunch of bees in the closed flowers, is that likely to be a male squash bee?
Dr. Lopez-Uribe:That is a great observation. Yes, so some males and this is true for solitary bees, males emerge and they don't really have anywhere that they call home where they can go back and, you know, protect themselves. So a lot of male bees use other structures and squash bees actually sleep inside wilted flowers. So it's not rare to open a wilted flower in the morning and see a bunch of cute males.
Lisa:Just you know, like waiting there, it's like they've been propping up the bar all night, right, of course the description of the male foraging behavior in the booklet is hilarious.
Pam:Yes, do tell, do tell. They hop from flower to flower in search of a female and they'll form these large ball of bees that will fall right out of the flower.
Dr. Lopez-Uribe:Oh yeah, that is. That is just a treat to watch. You know, like the male's going crazy and you know this is very common. Pollinator porn--Yeah, you can call it that.
Lisa:But she won't, because she's a professor. But we can, it's our podcast.
Dr. Lopez-Uribe:That's very common for solitary bees that nest in aggregations. So I've seen those behaviors in you know several species. Where you see those nest aggregations underground. You know when the females are first emerging. Usually the males emerge a few days earlier. So it is not uncommon to see that scouting behavior, for you know females and yeah, so they're hanging around waiting for the ladies.
Lisa:Okay, so we've been talking a lot about solitary bees and we should probably backtrack for a second and explain for our listeners the difference between social and solitary bees and who's who.
Dr. Lopez-Uribe:Yeah, thank you for reminding me of talking about that, because that's a huge misconception that a lot of people have. I think we're mostly introduced to bees through honeybees because I mean we do bee keeping, we know about honey and we learn about the fascinating societies that these bees have. But the reality is that, the social behavior of bees is really actually rare among these. So about 90% of the bees do not form any sort of group and really the definition that makes a bee solitary is that the mom will never meet the brood, by the time the, the new generation emerges, mom is already dead in the solitary bees. In social bees, mom interacts with the other generations in the colony and that can be one or several depending on the different species.
Lisa:So most bees are not like honeybees, not social bees.
Pam:Well, when people hear the term ground nesting, they immediately think of a run-in with a yellow jacket, a hornet, and that's what they think of. So they can't really see beneath the ground to see what's going on. So in the case of a squash bee, for example, could you explain the nest architecture, how the female proceeds to build her nest and provision for her young?
Dr. Lopez-Uribe:Every time that I tell this story I just it makes me think about how fascinating this is.
Dr. Lopez-Uribe:So again, these species, are solitary.
Dr. Lopez-Uribe:Each female has to do everything for her nest, including digging these like deep tunnels underground, and so there is usually kind of a main tunnel that is what connects to the surface, and from the outside these nests look like you know, ants nests, like there is kind of a little mound of loose soil from the stuff that the female has been digging out, and then from that main tunnel that are secondary tunnels that branch out, and then at the end of those secondary tunnels the female makes what we call a cell, which is really the cavity where she's going to put all the pollen and nectar for the developing larvae.
Dr. Lopez-Uribe:So basically, you know she's going to dig these tunnels, make this cell and they line the cells with some salivary secretiosn and abdominal secretions to make them a little bit protected from water and other things, and then she goes out of the nest, collects all the pollen and nectar, brings that back, and then, once there is enough food for one cell, then she lays an egg and then she closes that cell and then she will never see what happens after that. And she does that throughout her life. Depending on where squash bees are, they can probably make, I would say probably like about 10 or 12 of these, cells in the season. So yeah, compared to, for example, honeybees, the reproductive output of these solitary bees is significantly smaller.
Pam:Oh, that's so interesting. Yeah, is it safe to walk around the mounds? Because somebody will probably ask this-- Is it safe to walk near and around?
Lisa:Because, like, if you go to pick your own pumpkin or something like that, people might be worried.
Dr. Lopez-Uribe:Yeah, yeah, so that's a really good question. Most female bees have a stinger. So if you step on them or you know, if you try to grab them, they will sting you because they will feel threatened. But solitary bees don't have the same defensive behavior than social insects do. So that is the main difference between the solitary bees making their nests underground. So unless you're walking with bare feet and you step on a female, they won't feel threatened and they won't try to sting you. If you walk by, if this happens with a yellow jacket or a bumblebee nest, right, there is that defensive behavior and there is a higher chance that you will get stung.
Lisa:So squash bees are pretty peaceful, pretty easy to coexist with. Yes, so it's safe for us to walk. But we wouldn't want to do that right?
Dr. Lopez-Uribe:I mean disturbance happens right, either by us or animals who may be walking by. So the worst that can happen is that basically, when the when the bees-- and this is true for all bees-- when they leave the nest, they do something that is called an orientation flight, and so basically they leave the nest and they check for a few landmarks to know how to come back home,
Lisa:We like to look from all angles.
Dr. Lopez-Uribe:Yes, there you go and then you say, okay, I'm next to this green car, right, of course, but if that green car leaves, we may be a little bit disoriented. So the same thing happens with bees. The worst that can happen is that it may take them a little while to find their way back to their nest, and we've done some studies on , their behavior. They do make mistakes sometimes, so sometimes they enter the wrong nest and then if the female is there, the other female is kind of like pushed out and she's like no, this is my house. You go and look for your house. Yeah, I think that's probably the worst that can happen. Generally it's not a terrible thing to do to walk nearby.
Lisa:Good, good. And as far as the appearance-- again in my Cucurbit patches, I'm always looking, every year, I'm just looking for those tunnels, you know, like what's the diameter of the hole? Kind of what size are we looking for?
Dr. Lopez-Uribe:I think in centimeters. So I would say a half a centimeter--t he bee should be able to, you know, go inside the nest. When I see bee nests that have a smaller diameter, usually it's a sweat bee, that's going to be smaller, but definitely they are larger than an ant nest.
Lisa:So would it be like a pencil? Pencil eraser type.
Dr. Lopez-Uribe:Yeah, that's a great way of explaining the size.
Lisa:Well, I'll keep looking. I haven't got lucky yet, but I'll keep at it.
Pam:The photographs on your website of the nests are a wonderful way for people to see what they look like. The aggregation under the squash plants is beautiful.
Dr. Lopez-Uribe:Yeah, and they can nest in those aggregations, but it's not uncommon to see maybe just one nest --so there is some flexibility on whether they decide to do these large aggregations or not.
Lisa:Okay, so diet. So they're what we call a specialist bee, right?
Pam:Yeah, yeah, we want to know about the pollen.
Lisa:Yeah, just what is so great about that pollen? Is it like the pumpkin spice flavor, or what?
Dr. Lopez-Uribe:No, it's so, you know, it's a fascinating story and I don't think we know everything yet. These squash bees, which, by the way, we only have one kind in the eastern part of the US and in Canada, but there are about 22 species in, you know, in the Americas, right? So this is just kind of like one that we happen to have here, but in the South there is greater diversity, and all of them exhibit these very narrow, tight association with Cucurbit plants. So this is not totally rare to have bees that have that very close dietary specialization. What is special about this pollen?
Dr. Lopez-Uribe:We don't know. Something that we do know is that honeybees and bumblebees cannot eat this pollen. When you see bumblebees and honeybees in a squash flowers, they are drinking nectar and if they are leaving a male flower, you will see them standing on a leaf, kind of like grooming out the pollen because they don't bring it back to the nest. There are some experiments that have actually demonstrated that if you only feed Cucurbit pollen to bumblebees, they actually die. Like the colony cannot reproduce, the females get really sick. Apparently, there is something about the structure of the pollen that actually damages the gut of the bees. So, yeah, so it's fascinating and we don't really know how is it that these bees develop or, you know, evolve these high specialization on a floral resource that seems to be completely unused by other bees.
Lisa:Wow, that's so interesting because I see bumblebees all the time in there.
Lisa:NI have something else to watch for, which is great.
Pam:That's a fun squash bee fact if I've ever heard one.
Lisa:For sure, and I know a lot of your work has sort of centered on commercial growing. Pennsylvania, I think, is second only to Illinois in commercial squash production. So what I want to know, and what probably our listeners would like to know, is how can we encourage squash bees to make a home in our home gardens?
Dr. Lopez-Uribe:Yeah, I think it's fairly simple. You know I've done it in my house. I live in a suburban neighborhood, there are not a lot of agricultural fields in close proximity to my house I f I have like six plants in my garden, squash bees find their way. Of course, the more plants you have, the more bees you will be able to support. But yeah, really is all about having the plants and the bees will come.
Lisa:Yeah, and being sure not to till right? Don't till up the ground.
Dr. Lopez-Uribe:Yeah, I think that the story with the tillage is a little bit more complicated than don't do it. It is the deep tillage that is very bad, but actually the disturbance of the soil at the kind of surface is actually not a bad thing because it's loose for the bees to use right and to dig. So it's kind of this intermediate tillage that is the sweet spot for squash bees.
Lisa:Well, that's good to know and I found that interesting that the next generation will come can come back to that same spot. This was my question as a gardener who has struggled with squash bugs, which is totally different, you know, and one of the things that they always tell you, if you have a problem with squash bugs, is to not plant in the same place every year but to rotate around as much as you can. But I would think, in a typical suburban garden, it's not so big that they're not going to find it if you're rotating the plants, right?
Dr. Lopez-Uribe:Yeah, I guess it's because some of them, I think the life cycle of squash bugs, they need like the roots of the plants, so if you don't remove the plants, then they will kind of finish the life cycle. But the rotation of the plants, as long as it's not too far, it should not be completely detrimental to the bees either, they will find the plants.
Pam:Good, I have one more question.
Pam:I'm so fascinated by ho the population expansion of squash bees, with agriculture moving east, could you talk a little bit about that? That's so fascinating. When other pollinators are on the decline, the squash bee populations are expanding.
Dr. Lopez-Uribe:Yeah, it's a fascinating story and the story is that squash bees are not totally native to Eastern North America. They are here because humans, with the domestication and cultivation of the plants, basically created habitat for these squash bees outside of where they are native from, which is really deserts in the southwest of the US and northern Mexico. So, yeah, it really is a great example of how humans have modified ecosystems since a long time ago. We are modifiers of our environment and the power that providing floral resources for bees has. So, basically, by creating these habitats, these bees have been able to move with humans and establish and flourish. So I think, for Master Gardeners, I think this is a very empowering story. If you provide the floral resources, in many cases that may be the one thing that a bee needs to establish in an area.
Lisa:So if you plant it, they will come. They will come.
Dr. Lopez-Uribe:And this has happened in many different systems. We think that species are locally extinct, right, and then people plant the right floral resource or look for them in the right plans, and then the bees are there. So, yeah, I think it's a fascinating story.
Pam:Thank you so much for taking the time.
Lisa:Yeah, we really appreciate it and, listeners, we will include a link in the transcript of this show to the wonderful booklet that Dr Lopez Uribe has put out: The Biology and Pollination Services of the Squash Bee. It's really great and it has been my Bible in learning about the Squash Bee. So, anyway, we just so appreciate you taking the time and we wish you a very happy Thanksgiving.
Dr. Lopez-Uribe:Thank you, you too, and thank the Squash Bees for all the Squashes that you always eat and all the pumpkins in Halloween too, thank you.
Lisa:Of course, pumpkin and squash aren't the only foods on our Thanksgiving table. Another dish that's very traditional is cranberry sauce. Now, some people like to make fresh cranberry sauce.
Pam:Oh, that would be me. I like the fresh cranberry sauce.
Lisa:And still other people have special recipes for various salads or desserts with cranberries, but it's really an all-American plant the cranberry. Now you might think of cranberries as growing in bogs in places like in the northeast New Jersey, Maine, but it might surprise you to learn that cranberries are actually native to parts of Pennsylvania too. Wild cranberries grow in the very acidic and glaciated soils in the northern parts of PA, and it's the cultivated varieties of these wild plants that are commercially grown for our Thanksgiving table. Now, originally, cranberries were called cranberries because of the shape of the flower, which, if you look at pictures, you can see the resemblance to a crane's beak.
Pam:And those flowers are interesting because, although the anthers and stigma are present on the same flower, they don't mature at the same time, so they can't self-pollinate. So rather they need bees to move the pollen from the mature anther to one flower, to the stigma of another.
Lisa:And that is where bees come in. Commercial growers will tend to truck in managed honeybee hives for the flowering period, but wild native bees are also really effective pollinators of cranberries. According to Rutgers University, there are over 20 different types of native bees that visit cranberries in New Jersey alone. Take bumblebees. They are excellent pollinators and they work longer hours than honeybees, and they can forage when it's too cold or wet for other bees. So they really come into their own in adverse weather conditions and heaven knows, we seem to have plenty of those these days and we will also find mining bees and leaf cutter bees and sweat bees and cranberry bogs, and they're all important to a good cranberry harvest. So thanks, wild native bees.
Pam:So when we think of some of the side dishes at the Thanksgiving table, such as mashed potatoes, yams or stuffing, I'm getting hungry. Many times, at least at my house growing up, they were mixed together with creamy butter, milk or cream. And you might ask well, what in the world do dairy products have to do with pollinators? Well, as it turns out, dairy cattle benefit from eating bee-pollinated alfalfa and clover. Alfalfa is so highly nutritious it's a forage crop, an excellent source of energy, protein, fibers and minerals for dairy cattle. Cattle flowers must be cross pollinated to produce seed, and this involves the use of the alfalfa leaf cutter bee to acquire and move pollen among plants in the field.
Lisa:So there's a special bee for that.
Pam:There's a bee for that. So when you dig into those creamy mashed potatoes, you can thank this very efficient pollinator.
Lisa:So I hope this has given you some food for thought, listeners, and maybe some topics for discussion at your holiday table, maybe some topics that don't center around your personal life choices.
Pam:Or the latest political environment.
Lisa:So if you visit our website, you will find a downloadable Thanksgiving placemat that Pam created for us that you can print out
Pam:And, if you'd like, you can take a photo of your completed placemat next year feast. Email it to us and we'll be happy to share it on Facebook, instagram and on our website.
Lisa:And in the transcript of this show we'll provide a link to that and also a link to Dr Lopez Uribe's excellent booklet on the Squash Bee.
Pam:It has the most amazing illustrations and it's a really great resource.
Lisa:Yeah, it's incredible that it's just available to download for free. So take advantage of that, and we want to wish you and yours a wonderful holiday season, and we'll talk to you again in the new year. Happy Thanksgiving. RESOURCES: Thanksgiving placemat: http://www. snetsingerbutterflygarden. org/activities. html. Squash Bee Biology Booklet: https://lopezuribelab. com/squash-bee-biology