By Lynn Horowitz, docent at Tilden Nature Area of East Bay Regional Parks. Photos by Rollin Coville and Marissa Ponder

Transcription

1 What s the Buzz about Bees? Without bees, there would be no cherries, melons, or almonds. In a Berkeley campus garden, researchers are working to make sure the world s top pollinators keep busy. An interview with Dr. Gordon Frankie, UC Berkeley s research entomologist who studies native bees in an experimental bee garden at the University of California Oxford Tract in Berkeley, and at 10 sites throughout California. By Lynn Horowitz, docent at Tilden Nature Area of East Bay Regional Parks Photos by Rollin Coville and Marissa Ponder Dr. Frankie, would you start by giving us some background information about bees? For example, what s the difference between honeybees and native bees? Most people assume that all bees come from a highly socialized beehive with a queen, drones and workers, but native bees are different. With the exception of bumblebees, most bees have a surprisingly solitary lifestyle. Honeybees are generally the species of bees that people think about. This is because they pollinate crops and produce honey. Honeybees have become our favored pollinator because you can put them in a box and transport them to just about anywhere and they ll provide what we call ecosystem services. In other words, you can just put them where you want and they ll pollinate your crops. We have figured out how to make this an almost fool-proof process that works with large numbers of honeybees, which is why they are so important to us. Many people are surprised to learn that honeybees are not actually the most efficient pollinators. Native bees, which behave differently from honeybees, are more efficient and effective pollinators. Do native bee species have different seasons than honey bees? Yes, that s another difference, and our research has revealed new information about seasonality. Native bees emerge during different times of the year because seasons vary across bee species. Few farmers have considered bringing a huge diversity of native bees into an agricultural area even though it s possible. During our research, we found that bees need to be provided with habitat (floral resources and nesting areas), and that they also have their limitations. For example, they won t be as populous, and they don t like to be put in boxes or transported (except for a couple of species). It s easy to see why farmers prefer honeybees; native bees just seem to need too much!

2 You mentioned the floral resources that bees need in their habitat- what is it exactly that bees are collecting from flowers? They re gathering nectar and pollen. Nectar is a sugary carbohydrate that adult bees use for flight fuel. Pollen, on the other hand, they use primarily as a source of protein, vitamins, and essential oils for the growing larvae to feed on in the nest. It is also a component of bee bread. What is bee bread? Bee bread is a mixture of pollen and nectar that the adult female collects and places in her nest. She lays eggs on top of the bee bread and then dies after completing her nest. The eggs will hatch into larvae and feed on the tasty meal left by their mother. What else is on the list of what a bee needs? Besides the floral resources that they like, they need nesting materials substrates such as pre-existing cavities, or kinds of soil and dirt mounds that they like. Native bees need a seasonal sequence of nectar and pollen from February-October to support native bee seasonality. Native bees are unable to create nests in heavily mulched areas. Many home gardeners and master gardeners seem obsessed with mulch, and I think that s one of the big problems. Bees like and prefer a variety of nesting materials, such as little berms, rock walls, bare soil, adobe walls, tree holes, cavities You know, you can easily put bee boards out there. Is that the same thing as a bee condo? Yes, a bee condo is another way to describe a bee board, which is a wooden board with 3-4 deep, dead-end holes. Bees will make nests in these holes. About 70 percent of the bees in California are ground nesters, and 30 percent are tree hole nesters or cavity nesters. Once you figure out what they like, then you can figure out ways to provide them with the soils or cavities, or whatever, and they ll come. Is it easy to include native bees in a farm once you have set up the nesting mounds and planted the right kinds of flowers? Theoretically, it should be easy, but until we can demonstrate it convincingly, we still have a lot of work to do. One of the things that happens with solitary bees is we don t know how much variation they have from year to year in their population numbers, and we don t know much yet about their active parasites and natural enemies. We still have much to learn about them. Is Colony Collapse Disorder, the sudden decline in bee populations, caused by a lack of diversity within honeybees habitats? First, this CCD phenomenon is not new. It s happened a number of times, but no one has ever figured out what s going on, and so it continues to occur. We see it recur primarily in managed colonies and croplands, whereas urban areas don t seem to have this problem probably because they don t have nearly as many stress factors bearing down on them. The leading theory is that there is a combination of stress factors that are probably putting the bees in a vulnerable position. This causes a compromise of their immune systems, and viruses that they normally carry around with them are actually taking over and killing the bees. But until CCD is more thoroughly researched, we won t know for sure.

3 Digger bee sipping of nectar. Photo: Rollin Coville Can native bees help with the Colony Collapse Disorder (CCD) that seems to afflict bees nationwide? Should farmers include native bees in their farming practices? Well, we think so. We re trying to find out if native bees can be employed as supplements alongside honeybees. And the farmers we re working with so far in Brentwood, Contra Costa County (Northern California) haven t had much of a history yet of CCD. I think it s because they manage their bees differently than a lot of the huge farms, for example, almond growers. We also know that about a third of the crops that we normally use are dependent on bees for pollination. We have seen why farmers prefer honeybees for this purpose, but as I said earlier, research has shown that native bees can do a lot more pollination than people give them credit for. One particular species of bee, the Blue Orchard Bee (BOB), only needs 300 bees to pollinate an entire acre. So your work is really at the vanguard of bee research, especially with regard to your work on innovative solutions for the challenges that farmers face. Are you the first entomologist to encourage the use of native bees? No, many others have made the same observation, but basically the reason why our work is different is because, first of all, we re using a lot of the ornamental plants that people normally use in their gardens, including lots of natives. We re also using a large variety of species because each ornamental type of plant attracts a different kind of bee and this bee-plant relationship is predictable. That s what our work has shown throughout the state of California. We did our survey work in urban areas. So are you saying that many of the flowers that attract native bees are not necessarily native flowers, but are exotic ornamental flowers? It s a combination of both natives and non-native plant species. It depends on a variety of factors, for example, the location we re working with. It s not easy, but over a period of six years, we ve been able to record bee species diversity throughout the state. Some areas in the city of Berkeley alone have 85 species of bees, native as well as honeybees. Ukiah has 95 species, and Descanso Gardens in Southern California has a 105. So, if you look, the bees are there. And of course they come in all sizes, shapes, colors, forms, etc. Our upcoming book is based on years of intensive study in city gardens from Redding all the way down to Palm Springs, including Sacramento, Berkeley, Santa Cruz, San Luis Obispo, Santa Barbara, Descanso Gardens and Riverside. We ve developed a list of the most common bees that are out there, as well as the most common native and non-native plants that they visit. Our book will include 100 different plant types, 50 of which are really common and guaranteed to draw all bees, and another 50 which are a little bit iffy but, if you have a diverse garden, they ll probably work. What do you want people to know about the impact of what they are planting in their own gardens and what they can do to attract native bees? I think we want people to know that, though they may think their contribution is just minimal, they can play an important role in conservation. If you get enough people in a community

4 working and thinking about this, then suddenly it becomes an awareness point. CCD has actually helped us in this regard because it has raised awareness about the important role bees have for pollinating crops. We want to get more information out there to a broader audience, especially through popular publications like Sunset Magazine, but they ve been a little reluctant, perhaps because of the sting factor. The sting factor? While many people believe that a garden full of bees puts them at risk for bee stings, contrary to conventional wisdom, bees are not aggressive, and not all bees sting. Only female bees are capable of stinging, and are simply too busy to take notice of humans. During the course of years of research, we have stood within inches of thousands of bees in action, and we have never had to wear protective gear, and we have never been stung! Further, botanic gardens are usually full of bees, and they don t bother human visitors. Male Teddy Bear bee. Photo: Marissa Ponder Do native bees sting less than honeybees? Here s what we like to tell people: native solitary bees, have a list of three things they re interested in: pollen, nectar and sex. And we tell people, You re not on that list. Don t worry about getting stung! (laughs). The humor of that gets their attention. We also tell people another piece of information that s very, very important for them to know: bees are vegetarians. It s the wasps that are carnivores, and only a few of these will go after your hamburger and hot dogs. It is a little known fact that many wasp species are beneficial in the garden because they parasitize or feed on plant eating insects. We try to show people that bees are really quite benign and uninterested in humans and that they re doing a huge amount of services for us without even being paid! What about the relationship between gardeners and bees? Gardeners usually have a single aesthetic perspective and, generally speaking, do one thing: They look at a garden from a distance and they look at all these characteristics: the green, the colors, the little stream going through there, the path, whatever, so I always ask people, How many of you get up close and look at the flowers to see what s going on there in detail? Only about one or two people in any audience ever raise their hands. Most gardeners don t know a whole lot about bees. Mulch Madness is often promoted by gardeners for water conservation and for suppression of weeds, however, this practice discourages ground-nesting bees. When these bees are nesting, the female must find a patch of bare dirt, excavate a tunnel and then make repeated visits between the tunnel entrance and flowers for pollen and nectar. If a nest-searching female encounters 1-2 inches of mulch or black plastic, ( Black Plastic Insanity ) where there should be bare dirt, she cannot excavate through this material, and will leave in search of a better site. When a high number of gardeners in an area mulch or plasticize their soil, this can have a negative impact on bee populations.

5 Why are bees important? Why should people care about bees? Well, first of all, native bees are a part of the natural heritage of the land. They re just like every other organism that has a place. They ve co-evolved with plants. There are roughly 5,000 angiosperms, with probably another 1,000 that could be added if you counted in factors such as variety and hybrids. All of these plants need to be pollinated. I mean, they do have alternate ways of reproducing, but a lot of it has to do with pollination. So, if you start putting native plants in your garden, you can pretty well expect that native bees are going to show up and do some work. Urban bees provide a reserve of bee diversity consisting of thousands of pollinating species that can safeguard against CCD and current monocultural farming practices. How do bees pollinate? Are they pollinating flowers on purpose? No, pollination is incidental. Pollination is also known as the study of contamination. The pollen sticks onto various hairs on the bee and transfers to other flowers, resulting in pollination. What is the buzzing sound that bees make? The noise comes from bees when they are vibrating their wing muscles. Larger bees like bumblebees are capable of buzz pollination. When these bees visit tomato plants, for instance, they hook onto the flower and use their wing muscles to buzz off the pollen. Do different kinds of native bees have different kinds of behaviors? Very much so! In fact, every bees has it s own story. And that s something that we try to point out to people. Just as every bird and every mammal has different characteristics within their species, each bee has its own characteristics. Once you get used to that fact, you begin to realize that there s a huge number of stories that have yet to be told. There are 1,600 different kinds of bees in California alone! In the U.S., there are approximately 4,000 species. In the world, there are about 20,000! How are urban areas different and less stressful to honey bees? Urban areas have a lot of wild bees wild honeybees which are not managed. So these bees are free to come and go as they please. They are free to go pick from as many different sources of food that they want. Some honeybee experts have told me that this is a very important factor; even beekeepers know this. A diversity of plant sources is necessary for the health of the bee population. Also, no one is spraying them with pesticides regularly, unlike in managed croplands, for things like mites. And nobody is moving them miles and miles and giving them only one plant choice to feed on. For example, the reason why almond growers are so concerned about this is because almonds are obligate outcrossers. The growers have to have a cross between different types of almond trees, genetically speaking. That is, they need a variety of almond trees and they need to cross pollinate. In contrast, bees are less stressed in urban areas because they don t encounter pesticides, there are a lot of different plant materials, and the bees don t get moved around. Beekeepers have actually written about this, and noted that urban areas Male Long Horned bee. Photo: Rollin Coville

6 don t have the colony collapse problem. That suggests that the bees are telling us something important. Early reports in 2011 suggest that honeybee numbers are increasing, and this may be due, in part, to some management changes that are being made by beekeepers. Female Leafcutting bee. Photo: Rollin Coville Do you believe that native bees can act as a supplement to honeybees in their role as pollinators? Yes, that s the way we are viewing them, as potential supplements to honeybees in these field situations, and we think we will be able to demonstrate as we get more native bees into a field that they are also effective pollinators. The amount of supplementary pollination you ll get, and how many bees you will get, will depend on how much of the habitat you are willing to create for them in the field. Generally, I would say that the bigger the habitat, the more pollination. How do the honeybees get along with the native bees? Are there any battles between them? We look for it and haven t yet detected any aggressive behavior. All we observe is one or two more kinds of bees visiting flowers, going about their business, and we think that s the way it s been naturally for years anyway. Honeybees are just one more bee in the mix. Are there any simple steps that can be taken to improve the habitat on farms for native bees? The first thing farmers can do is to recognize that they ve got to create native bee habitat. That means providing floral resources that perhaps they haven t considered up until now. And in this regard, these little wimpy hedgerows that don t have many plants in them are not going to do the job. Farmers who are committed to this effort will eventually have to give up some space in their fields. Probably in the center would be better. This would allow for biologists to create habitats where we can demonstrate that these kinds of modifications are going to bring bees in that will be part of the overall pollination services. Without that, and with continued reliance on these skinny little hedgerows, it s not going to happen! It sounds like you re an advocate for new farming management practices! I m for open gardens and I m for opening spaces up. You can do that, especially in orchard fields, because there are always trees that will die. A farmer can remove the dead tree and, during the time it takes before a new tree can grow again, cultivate that patch with annual plants that the bees like. Annuals are a good choice because they will die out after a year; perennials are good too, but it takes extra work to remove them. The main thing is you ve got to get designated spaces available for these plants. And you ve got to look at whether that percentage of space that can be given over to a bee habitat will be enough to bring in the bees and build up the bee population. That s part of the formula. The other part is bees need to have resources where they can nest. We still have a lot of work do to do on that. But the bees are there they re coming in.

7 Why are urban gardens important to native bee populations, since urban centers are generally not close to farms? Can urban bees fly the necessary distances? Native bees are losing their wildland habitat to increasing urbanization and fragmentation of the landscape. Part of the solution to conserving native bees is providing them with adequate urban habitat. Sure, they ll fly over to farms, but they are also considered to be a genetic resource that can eventually someday be called upon because cities are housing bees, unknowingly cultivating them. This is not a new concept. Back in 1991 in England, Jennifer Owen said these bees in urban areas are serving as genetic resources, like a kind of bank. We are finding Owen s work to be true in California as well, and many of the bees that we have identified in urban areas are the same exact species as the bees in agricultural croplands. This leads to another question about habitat, ecology, and diversity. Among environmentalists there is currently a bias against non-native plants. How do you feel about this trend? Is there a place for non-native plants in the bee world? Earlier you mentioned ornamental annuals and perennials in the context of farmers designating floral resources for bees. Can exotics also be useful in the habitat? First of all, I think it s not very useful to think about native versus non-native. What s really important is, what do the bees like? You have to look at a habitat from the standpoint of what does a bee like and what does a bee need? And if they need non-natives as well as natives then you should be thinking about putting both those types together. Natives are really good, there s no doubt about it, but natives are really best in the early season, i.e., spring and early summer. Non-natives become really prominent in summer and in the fall. So there s no reason why you shouldn t use a combination of natives and non-natives. In fact, this combination actually encourages people to plant more natives than they would otherwise, and is the reason we combine natives and non-natives. Furthermore, a lot of these non-natives, such as Cosmos and others like Salvia uliginosa and Salvia Indigo Spires, are wonderful plants for both pollen and nectar. There used to be a fear about the African bee migrating north. You don t hear much about them anymore. Are they still a threat? The Africanized bee still exists in Southern California. It came in with a big roar, and scared a lot of people. There were some incidents of people and animals getting stung. But we haven t heard much about the African bee recently. In fact, once people realized they had a colony of African bees which were more aggressive, they managed the situation by calling exterminators and removing them. So I think it s not as bad as it was, but the potential for stinging and that crazy behavior to erupt in Africanized bees is still there. It s just not as much a concern as it was because we now know how to deal with it. Because honeybees are non-native, having been introduced by European settlers many years ago, The Nature Conservancy has removed them from some of the land that it owns. In San Diego, for instance, when these honeybees were evicted, the Africanized bees moved in. What do you think should be done for the non-native honeybee? Well, there s also this policy of removing these bees from Santa Cruz Island, for example, in the Channel Islands, and because it was an island, they could do it effectively. There s been some follow up, but it takes years to figure out if it s truly made a difference. You know, people are obsessed with this idea of it s not native then they should get rid of it. But I think that that you also have to be really clear about your goals. If you re obsessed with non-native removals then

8 you re going to get rid of them. But if you can live with them and you realize they re not really causing any harm and you have some use for them, then why remove them? Removing those bees from Santa Cruz Island took years, and was quite costly. But if that s your goal, then you have to follow it. What damage were the bees doing on Santa Cruz Island? Well, first of all they were occupying a lot of spaces, and pollinating a lot of the non-native weeds, the European weeds. It s a complex issue. In the years since the bees removal, it s been difficult to tell what s different because there are so many native and non-native plants involved. Researchers from UC Davis and UC Santa Barbara are still in the process of evaluating the data from this study. Are you suggesting that the role of non-native plants might have evolved to serve an ecological function that isn t really understood until they are removed? Yes, and that happens also with plants. For example, there are many people who want to remove Eucalyptus wherever they can. But then there are the Eucalyptus lovers who say that Eucalyptus trees are good. They provide places where Monarch butterflies will hang out during the winter and where the great horned owls and egrets will nest. Hummingbirds also use the Eucalyptus flowers for nectar. So there are some actual ecological reasons why these plants and organisms having been randomly brought together have adjusted themselves to our environments, and they become useful even in the minds of people who are conservationists. It s fairly easy to demonstrate that these native organisms have begun to use these non-natives for their reproduction and survival. It is worth noting that Dr. Art Shapiro at UC Davis says that native California butterflies now depend on non-native weeds for their survival. If you suddenly remove these, what happens? The land doesn t necessarily return to its earlier habitat as people envision. Have you had experience with this non-native management issue in your work? Yes, we re planting a lot of native plants in croplands in the Brentwood area, and they re being overwhelmed by non-native European weeds. This is a new challenge for us. We have to figure out how to manage these weeds so that the natives will grow better. For example, if you plant tall perennials, that would be really good because they ll cover the land and grow over on top of the weeds. But if you think you can just spray native seeds out there and natives will just pop up, it s not going to happen. You have to know what you re doing when you manage a piece of land differently, because the plants will respond to what you do. We re not going to use herbicides, so we may have to manually remove the weeds to help the natives get started. This is all new for us. We also are going to be looking for the right plants that can rise above the weeds, some of which may be non-native. Can you recommend some nurseries where people can buy native plants, and other bee-friendly flowers? Definitely: Berkeley Horticulture, Mostly Natives in Tomales, the Native Nursery in Tilden Park, Native Revival Nursery in Soquel the prices are really good and they have good plants, and there s a place near the UC Santa Cruz Arboretum. Annie s Annuals in Richmond, Watershed Nursery in Berkeley, and Flowerland in Albany are also great resources. If you don t mind the drive, the Santa Barbara Botanic Garden has a large collection of wonderful native plants.

9 Would you recommend some good books for gardeners who want to attract bees, including your own upcoming book, of course? Bees, Wasps, and Ants, the Indispensable Role of Hymenoptera in Gardens, by Eric Grissell, Timber Press, and Attracting Native Pollinators by the Xerces Society. Also, a wonderful book by Jennifer Owen: Wildlife of a Garden, a 30-Year Study, published by the Royal Horticultural Society in London (2010). The tentative title for our book is: Bees and Their Flowers in Urban California Gardens, UC Press. We hope it will be out by early Notice the beautiful purple pollen on bee! Photo: Rollin Coville Can you give us a preview of your book, Bees and Their Flowers in Urban California Gardens? Bees are really interesting and we want people to read about them from a new perspective. The book includes general background information about bees, discussing why they re important, and then tells the reader how to identify the common bees. We also describe the specific plants that bees like. Much of this material is previously unpublished accounts based on our research. In the last chapter, we talk about the implications of our research and the useful applications of this new knowledge about bees. What kind of resources do you have on your website? Our web site, helpabee.org, is based on questions that people have asked us, and it s really geared toward homeowners. One of the most popular features of the website is the native bee plant list, which includes both ornamental native and non-native flowering plants that are known to attract a wide variety of bees. We have a section on myths and bee legends that debunks many of the misconceptions about bees. For example, people are scared of bee stings and we try to alleviate these fears by explaining that only the female bee stings, and furthermore, bees don t want to sting, they just want to do their job. As I mentioned before, bees are only interested in 3 things: pollen, nectar, and sex, and you re not on that list!