Introduction to the Pennsylvania Bee Monitoring Program

To assess the health and biodiversity of bee populations, Penn State Master Gardeners, for the last six years, have helped collect and identify at least 310 species of wild bees in Pennsylvania. In partnership with the López-Uribe lab at Penn State, these volunteers have contributed to developing a distinctive community science project that has produced critically important data on par with many expert researchers. Joan Jubela, Penn State Master Gardener from Wayne County, talked with Dr. Margarita López-Uribe, associate professor of entomology, about the contributions of Master Gardeners and the status of bees in the commonwealth.

Interview

Jubela: Are you trying to reach out to other parts of the state, to other counties, to recruit more Master Gardeners for the Pennsylvania Bee Monitoring Program?

López-Uribe: The Master Gardeners [in the program] do a ton of work, but ultimately all those bees that they collect get to my lab, and they need to be processed, pinned, labeled, and identified. Sarah [Kania] works the most with the volunteers processing the bees, but right now, we are basically at capacity. Something that we are considering is opening up [the educational part of the program to create more opportunities for engagement].

I've heard from several people here in Pennsylvania who are actually working with the Master Melittologist program in Oregon. This is a program run through Oregon State, but we could be offering those educational opportunities here in Pennsylvania, in case anyone out there is interested in learning more about bees or knowing how they can participate in the research.

Jubela: A melittologist? Is that someone who specializes in bees?

López-Uribe: Yes, I consider myself a melittologist.

Jubela: How many Master Gardeners are there who have been working with the program for the last five years?

López-Uribe: Roughly, it's been up to 25 people. Right now, we are working with 16 Master Gardeners. We usually have some participants who are not Master Gardeners, and despite the program running for 6 years now, we've had very low dropout rates, even though it's a project that involves a lot of volunteer time. Most of them seem to really enjoy it.

Jubela: Do these light gray areas on your map of Pennsylvania represent areas where there has been less collection of bee specimens?

López-Uribe: Yes, even though we have a lot of gaps in several counties, when we first designed this experiment, we selected Master Gardeners who would help us fill out the gaps. We still have more data from Philadelphia, near Pittsburgh, or near Centre County, but we are trying to get better coverage across the state. [Sometimes] Master Gardeners are moving out into other counties where they don't necessarily reside [to collect samples]. But we also have people from counties where there was nothing known about bees when we started the project, and we have slowly been building information about bees in those places.

Jubela: What are you learning? What observations have you made that reflect the biodiversity of bees in Pennsylvania?

López-Uribe: We have made significant advancements. The fact that we are increasing county-level data on bee diversity and data on what species are in different counties is very powerful. Nash Turley, [a postdoc fellow], oversees the data management and analysis. [Now that we have more] species-level identification, and we also know how abundant [some species] are, we can start asking questions about whether there are associations between certain types of bees and their habitats. We actually have a lot of non-native species coming into the state, and they pretty much get under the radar. No one has been paying much attention to that. We are also getting a lot of new records, [new bees we haven't seen]. [For instance] some species are changing their distributions either because of climate change or because [those species] are naturally expanding their ranges. We are basically documenting all of these [changes]. And I believe we have one of the best datasets for eastern North America on bee biodiversity across our state and longitudinally over time.

Jubela: Can you cite concrete examples?

López-Uribe: Yes. We published a paper two years ago, and at that time, we reported twelve new species in the state, "Bee monitoring by community scientists: comparing a collections-based program with iNaturalist".

Jubela: Wow, you mean twelve completely new species that aren't part of the 437 already recorded, is that right?

López-Uribe: Yes. Twelve new species. Now it's fifteen. The previous checklist reported 437 species. So now we have 437 + 15 [species overall].

Jubela: That's amazing.

López-Uribe: It is! But four of the new species are species that are non-native to North America. [That is a high] proportion of non-native species. It is pretty remarkable that we're finding so many. People don't think about non-native bees as problems, but those bees should not be here, and they're finding their way to Pennsylvania. Also, for example, some of the species that we [assumed were present] in Pennsylvania because we have records from Ohio and New York, but we had never recorded them in the state, now we can actually report some of those species as actual records. So yes, some of the biologically relevant data are new species or species we haven't seen in a long time that are being found.

Jubela: OK, can you give me examples of species that you are really excited about?

López-Uribe: I'm emailing you a list. These are rare specialist bees: Andrena aliciae [yellow-faced miner bee], A. clarkella [Clarke's mining bee], A. duplicata [a mining bee], A. gardineri [a spring mining bee]. And these other specialists: Habropoda laboriosa [blueberry digger bee], Colletes validus [blueberry cellophane bee], and Hylaeus fedorica [yellow-masked bee]. They are not very common at all and probably haven't been seen in Pennsylvania for decades, and now we have records of them.

Jubela: What are some of your Master Gardener community scientists learning?

López-Uribe: Wow! They are becoming amateur entomologists. They have a deep understanding of the biology, of biodiversity, and the natural history [of bees]. They are using the same methods that we scientists use to monitor bees. Many of them are curating their own specimens. Some of them send us the bees in bags with alcohol; some of them actually go through the process of washing them, pinning, and labeling them. That is the kind of highly skilled work that entomologists do. [Volunteers] go through a lot of hours of training, plus all of the hours where they're actually going into the field and putting that training into practice. They become highly skilled.

Jubela: What do you want people in the Master Gardener program to know about bees? What is important for gardeners to understand?

López-Uribe: There are a lot of misconceptions about bees and pollinators. Bees are way more diverse than most people recognize. I think the Master Gardeners working with us for so many years have a better appreciation of all the little differences in these diverse creatures in the state. Having almost 500 species of bees is a number that I find fascinating. It's important to acknowledge this diversity. About 34% of the bees that we have are specialists. They have a specialized relationship with [specific] plants. This really brings up the importance of using native plants to support biodiversity. A lot of non-native plants are good bee plants, but they're mostly supporting generalists. Specialists are more vulnerable to [environmental] changes and habitat destruction. If you're a gardener and you want to help the bees, then 'go native plants!' So, the knowledge and appreciation of biodiversity are important. But I think the other component, and this is a little bit harder to sell unless you're part of the program, is that our volunteers are getting a deeper understanding of the scientific process. I feel one of the aspects of this project that makes me feel very proud is that we are able to relate to Master Gardeners who are non-scientists – what we do in the scientific process, why things take a long time, why we need to collect data multiple years, and why we need to replicate the work. When science is under threat right now, when scientists are being challenged with the way we do things, I think that working next to people doing science is one of the most powerful ways that we have to elevate the importance of science. There are dual gains –one aspect is valuable to native bees and biodiversity; the other aspect is our involvement with people in the scientific process.

Jubela: You mentioned specialist bees being more vulnerable. Can you talk about that a little bit more? I'm wondering, why are they more vulnerable?

López-Uribe: We do a lot of work with squash specialist bees that are doing really well in human modified landscapes because the bees use squash plants which we are cultivating and growing everywhere so [in this specific instance] humans' modifications to the environment are good for the bees but when the plant [a bee is using] is decreasing for some natural or human mediated reason then of course the suitable habitat for those species is going to be significantly reduced. A lot of the bees that are currently being considered for some level of conservation status – many of them are actually specialist bees that are in decline. They are becoming rarer because we just don't have enough of their host plants.

Jubela: Let me see if I understand. A lot of wild bees are important for crop pollination, but many specialist bees aren't really involved in pollinating crops. Many plants, especially those that aren't crop plants, are becoming less and less present in the landscape. The specialist bees that pollinate those plants are particularly in jeopardy.

López-Uribe: Yes, one category of natural history among bees is diet (pollen) specialization. If you're a bee and you specialize in a plant that is cultivated in agriculture, or maybe a plant that is frequently used for landscaping, then your species is going to be more abundant. But if you're a bee and you just don't have enough to eat because the plant you frequent is becoming rarer in the landscape, then you're going to be in trouble. So that is one issue [impacting] specialist bees. But there's another kind of highly vulnerable bee, another natural history trait with some bees. These are called the cuckoo bees. I don't know if you've heard about them.

Jubela: Oh! Are they the bees that sneak into the nests of other bees? They steal from other bees.

López-Uribe: Yes, they're also called kleptoparasites.

Jubela: Kleptoparasites. It is amazing that there are kleptoparasites in the natural world.

López-Uribe: Cuckoo bees are also more vulnerable to changes. They are less abundant than their host species. Think about it, if they were equally abundant, then the host species would basically disappear because they are on a different trophic level [in the food chain or ecological pyramid]. So, if for some reason their host species is declining because of host specialization or because their habitat has been reduced, then these kleptoparasites become even rarer.

Jubela: So, it's as if there is a cascading effect.

López-Uribe: Yes. There are a lot of kleptoparasitic species that have become extremely rare, usually because their host species is also in decline.

Jubela: OK. Let's shift gears a little. Can you talk about what the long-term goal of the project is?

López-Uribe: [For one], our long-term vision is to generate data that is going to help conservation and management. Now that we have a better understanding of what bee biodiversity looks like in Pennsylvania, we are trying to use the data to answer all kinds of questions. For example, questions about habitat associations. Are there certain species more likely to be found in certain habitats? If so, then could we have programs designed to protect those habitats or enhance those habitats to support these bees? So those are the types of questions we're aiming to answer with the data. The other thing is that because now we have very good temporal data, we can start looking at patterns over time and identifying maybe species that may need to be listed as species of concern or declining species. One of the most difficult aspects of doing insect conservation is that we really don't have good data for insects at all, and so when people start noticing that something is disappearing, it's very difficult to list or to make those conclusions for insects because the data from the past is just absent. With bee monitoring data, we are positioning ourselves where we can actually answer some of those questions for bees. I think there is an inherent value for conservation and management, and that's one important goal. We are learning a lot about basic biology, ecology, and the natural history of bees. This information has a different scientific value. Primarily, our goal is to enhance bee populations.

Jubela: Have we known for a long time that there have been approximately 500 species of bees [in Pennsylvania]? Bees must have been collected throughout the 20th century, right? We have had some idea of the number of species [a checklist], haven't we? Was the data about bees just not very extensive? What was the need for this project?

López-Uribe: Well, yes, there was collecting, but basically the collections were not systematic. And a lot of insect collections, specifically bee collections [in the past], like before our program, they tended to be kind of opportunistic. One of the reasons why our maps [that show different species density from county to county] look the way they look, with Centre County and maybe Allegheny County and Philadelphia County being very dark gray [suggesting more species are present in those locations] is because that's where universities are found.

Jubela: Right. That's where the people doing the collecting were.

López-Uribe: Yes. Also, there are all of these biases in the way that we collect data. For instance, usually, taxonomists get really excited about rare species, and so they would go out and only collect the rare things, but not the common ones. And there are all of these problems with how data is collected without considering standardization in the effort. [All this means] lots of problems for the types of questions that we can answer with the data. The fact that we're doing [this bee monitoring project] in a standardized manner has a huge scientific value for the types of questions that we can answer with the [data we collect]. That's one of the primary reasons for [having started] the project and continuing with it over time.

Jubela: What are you learning from the data you are collecting?

López-Uribe: Okay. To give you a perspective, five years is not really enough time to [get deep insight into helping us answer some of our questions.] For instance, to detect [issues] like decline. Generally, you need 10 years or more to do quantitative analysis around measures of strength or decline. But in some initial analysis [that we have been able to do], we have quantitatively identified, for example, the species Osmia lignaria, which is a native mason bee. It used to be very abundant in eastern North America, and now it's becoming very rare. [With our data], we can actually detect these declines of this species over time very strikingly.

Jubela: Wow, OK.

López-Uribe: That's one of the bees that we think we are going to start paying more attention to and move into targeted monitoring. What we do with the actual monitoring is more like surveying. [It is called targeted sampling]. [This species] is one of the candidates that we may focus on. We recently received a small grant to fund a student to test some of these protocols for targeted sampling of certain species.

Jubela: OK – What family is that bee?

López-Uribe: Give me a second. I'll look that bee up in the pollinator guide that you guys [a group of Master Gardeners] put together: Bees of Pennsylvania: A Guide to the Genera.

So what family is that mason bee? OK, that family is Megachilidae. It's a beautiful green metallic bee, very large. There are two subspecies: One on the East Coast and one on the West Coast. On the West Coast, the subspecies is doing perfectly well. They are actually [reared for] crop pollination, and we don't know why [the subspecies here on the East Coast is in decline].

Jubela: What does that bee pollinate? Is it a specialist or is it a generalist?

López-Uribe: It does have a kind of preference for Rosaceae plants. So that's why it's used a lot in orchard pollination. It's not necessarily a strict specialist. It does have a broader diet. It is very good for pollinating apples, for example.

Jubela: Do you think pesticides could be affecting this particular subspecies? I mean, I know that pesticides are bad for bees. We read or hear about it all the time. But pesticides are so widespread. As Master Gardeners, we learn about Integrated Pest Management, and the use of pesticides is often the last resort. But all these pesticides do get used, and they're supposedly bad for bees, and I'm wondering from your point of view what effect pesticides are having on bees.

López-Uribe: I understand. Pesticides are needed for crop protection, but there's a lot of misuse of pesticides, and that's a huge part of the problem. For example, it's very well established in the literature that neonics [neonicotinoids] on seed coatings of corn and soybean do not protect crops from anything, yet it has devastating effects on non-targeted insects like pollinators and many other things, but we still commercialize it in the US [and there are a] lot of crops with neonic-coated seeds. But it is not necessarily a black-and-white situation. We do need pesticides in some instances. Of course, every time you use pesticides, you are going to be impacting non-targeted species like pollinators. That's important to acknowledge. That being said for [the species of bee we are discussing], for Osmia in particular, [while] I'm sure that pesticide misuse has negative effects on basically all these species, what is interesting about Osmia is the Western subspecies, which again is used for agricultural pollination [for apple production], it is doing fine, but here in the East, it is not. So, that tells us there is something happening, in addition to stressors like pesticides, and we just don't know what or why. We haven't been able to pinpoint or nail the reason for those declines [in the Eastern subspecies].

Jubela: I know you're from Colombia. How did you get interested in bees? How was that passion ignited?

López-Uribe: Yeah, I'm not going to tell you the typical story of being a child and always catching bugs. I grew up in a city, and my mom has a phobia of insects, so she would spray our apartment monthly. I didn't even see ants in my kitchen, so I did not have a lot of exposure to insects growing up, but I ended up studying biology in college. I took entomology, and bees were one of the groups that really caught my attention. When I found them in the field, they just fascinated me, the variation in sociality levels across different bees and their association with plants, and I was interested in plant diversity. So yeah, I just fell in love with them, and since I was an undergraduate, I have been doing research on bees.

Jubela: I think bees are the cutest insects.

López-Uribe: I agree with that statement.

Jubela: There are many bee monitoring projects across the country. These programs are trying to recruit people to be community scientists. Does your lab at Penn State work with these groups and various entomologists? Obviously, you share each other's papers, but especially as regards community scientists, I'm wondering if, in large part, others are emulating you because of the success of your project?

López-Uribe: There is a greater umbrella of monitoring, and we are part of that umbrella. Umm. I guess I'm going to share some of the differences between our project [and some of these other projects], and maybe I'm going to sound a little bit obnoxious because I think that our project is really good.

Jubela: Please go ahead. It's OK by me. [Laughter]

López-Uribe: Well, different bee monitoring groups have different capacities and different interests, right? So, I think there are a lot of projects out there that prioritize engagement with the public. The approach of those projects is more [inclusive]. Everyone can participate. Sometimes [as a result of this inclusiveness] there is a low commitment level on the part of participants involved. I think the goal of many community science projects is to really engage people in doing science and learning something about pollinators. That's great! Then [a project] can reach out to many more people. But there is a cost to focusing [on engagement above all else]. The quality of the data can be very low, and in many cases, scientists who have been doing those types of community science projects [with the public] for many years, decades even, there are some who say they cannot really use the data to [understand] much about anything. Maybe I'm being overly critical, but I have talked to colleagues who have been doing that type of project for many years, and it can be very frustrating for them because it's a huge amount of work, and then what they can use that data for is very minimal.

Jubela: What can you say about the Penn State Bee Monitoring Program that's different? Is it the training?

López-Uribe: Yes, it is the training and also the commitment of our volunteers. They are highly trained and can follow protocols that are a bit more complicated. It's not just like 'Look at a flower for three minutes and count the bees.' It's way more complicated than that. I think we kind of hit this sweet spot of engaging with a good number of people. Twenty-five is not a huge number, but our volunteers generate very high-quality data, and they have been doing it for five years. We hope we can continue to engage them for many more years, so that's another goal.

Jubela: What good news is there to report on the status of bees in Pennsylvania today?

López-Uribe: I think the rediscovery of the species of bees I emailed you. These are bees that haven't been seen for many years, not because they are extinct but because we haven't looked for them hard enough, or in the right places. So, earlier, you were asking me about the type of training that we give the Master Gardeners every year. We continue to monitor bees, but the project has changed over time, and one of the things that we are trying to do this year is to focus more on rare plants or plants that have a lot of specialists to see if we can find more of these rarities.

Jubela: Fantastic. What are some of those plants to attract specialists?

López-Uribe: [Here is a list]. Since 2023, we have focused on Ageratina, Asclepias, Cerastium, Desmodium, Erythronium, Eupatorium, Oenothera, Phlox, Solidago, and Symphyotrichum.

Jubela: What's next for the project?

López-Uribe: With better data, we can conclude whether some bees are locally extinct or if they're just rare and very difficult to find. You've asked, 'What is it that we're learning?' [Through our collecting], we are sacrificing all of these bees every year. What are we doing this for [you might ask]? With the data we're gathering, we are advancing our understanding of all these questions.