You may have read recently that backyard beekeeping is putting native bees at risk. The argument given is that honey bees travel miles from their hive, taking nectar and pollen from flowers, leaving insufficient resources for native species while also transmitting diseases to native bee populations.
Additionally, the argument further suggests that honey bees tend to pollinate weedy plants more than native plants, leading to the decline of native plant communities. This argument concludes that beekeeping should not be practiced in urban areas to protect native bees and plants.
Since Oregon’s rare or threatened native bee species occur outside of urban centers, claims that backyard beekeeping will result in the extinction of any Oregon’s native bee species are dubious. Here, we explore the science around the impacts of beekeeping on native bees and provide tips on how to help native bees while enjoying beekeeping as a hobby.
Urban beekeepers have a strong history of advocacy around creating bee habitat and native bee conservation. These efforts by beekeepers are entirely missed in the popular phrase: "You wouldn't keep chickens to save songbirds, so why keep honey bees to save native bees."
What are native, exotic, wild or endemic bees?
Native bees
A native bee species is one that found its way to a region without human intervention. You might imagine a native bee species to be one that evolved and adapted to conditions in Oregon. Evolution, however, is an ongoing process and some bees that are considered “native,” such as the rich fauna of masked bees of the Hawaiian Islands (Hylaeus spp.), only arrived a few hundred thousand years ago.
Native bees continue to move without human assistance. A great example of this is the squash bee (Xenoglossa pruinosa), which was unknown to Oregon until 2016, when the California native bee appeared in the Rogue Valley of Oregon. It is believed that squash bee migrated without human assistance to Oregon. We will undoubtedly see more changes like these happen to the ranges of native bees in the coming decades.
Wild bees
A wild bee species is one that lives outside of human management and that has not been significantly altered by breeding. All Oregon native bees are wild bees, although notably three have come under commercial management:
- The alkali bee (Nomia melanderi)
- The blue orchard bee (Osmia lignaria)
- The yellow-faced bumble bee (Bombus vosnesenskii)
Exotic bees
There are dozens of species of wild bees that have been introduced to Oregon. This includes a mason bee from northeastern Asia (Osmia cornifrons), which was introduced to aid in crop pollination, and two woolcarder bees (Psuedoanthidium nanum and Anthidium manicatum) that were accidentally introduced, likely through shipments of wood that contained nests. These introduced wild bees are known as exotic bees.
Endemic bees
In total, Oregon has around 900 species of wild bees. Most of these are considered native. Many of them are also considered to be endemic bees, which means they are only found in certain parts of Oregon and nowhere else on earth.
Oregon is extraordinarily well positioned to understand the status of its native bees, as well as the introduction of new exotic bees, because it has the Oregon Bee Atlas. The atlas is the largest contemporary survey of wild bees in the U.S. The data from the atlas is generated from Oregon State University Master Melittologists, who are part of the volunteer arm of the Oregon State University Extension Service.
Many bees that the Master Melittologists find do not at first glance look like a bee. Most of these bees will be unfamiliar to Oregonians. For perspective, consider one group of native bees most Oregonians are familiar with: bumble bees. There are only 25 bumble bee species in Oregon, all of which are native to the state. That is only 25 species out of around 900 total bee species in Oregon!
What do the rest of the bees look like? Some bees are easily mistaken for wasps or flies — some are even as small as a gnat. Most live in the ground, and one-fifth of the species — the cuckoo bees — do not even collect pollen but parasitize other bees. The world of Oregon bees is vast, endlessly fascinating and stranger than many can imagine!
If honey bees aren't native, where did they come from?
Honey bees (Apis mellifera) are an exotic bee that is native to a large swath of western Eurasia and Africa, comprising a massive natural range spanning from Scandinavia to the Cape of Africa, from the Atlantic coast to the Middle East. They were originally brought to Oregon along the Oregon Trail in the early 1850s, making honey bees one of the first exotic bees in the state. Given that honey bees were present in Oregon from the beginnings of European settlements, they are considered a naturalized bee species.
Honey bees are not domesticated like a backyard chicken, as they have largely escaped breeding owing to their unique mating biology. They readily escape management and become a wild bee through a process known as swarming. Swarming typically occurs in the spring when nectar and pollen are abundant.
The rapid growth of the colony triggers the colony to rear new queens, at which time the resident queen leaves with half of the workforce to begin a new colony in a cavity, such as a hollow in a tree. No other species of bee in Oregon swarms. These wild or feral colonies can survive many years without human intervention.
The vast majority of honey bee colonies in Oregon are commercial, with a small fraction kept as a hobby in backyards. The 80,000 or so commercial beekeeping colonies in Oregon are unlike those from other states that travel around the United States on trucks. Apart from traveling to California to pollinate almonds in February, Oregon's commercial honey bee colonies stay within the state, pollinating a variety of specialty crops and making honey.
How could beekeeping impact native bee species?
The concerns around beekeeping negatively impacting native bee conservation emerged around 10 years ago alongside prominent opinion pieces in high-tiered scientific journals. Subsequently, there has been a proliferation of research on honey bee impacts on native bee populations.
There are primarily three main areas of current research:
- Research evaluating whether honey bees outcompete native bees for pollen and nectar.
- Assessments of whether honey bees preferentially pollinate weedy plants at the expense of native plants.
- Studies determining if there is transfer of diseases and parasites from honey bees to native bees.
Do honey bees outcompete native bees for nectar and pollen?
A frequently cited conceptual paper by Cane and Tepedino points out that the seasonal pollen consumption of a honey bee colony is equivalent to the resources needed to rear 110,000 solitary native bees.
Solitary bees comprise around 75% of native bees in Oregon and these nest as single individuals and do not form large colonies. They calculate that 40 honey bee colonies placed in wildlands would consume the pollen equivalent to 4 million solitary bees. Such an approach to the issue of competition, however, hinges on broad generalizations on the biology of both honey bees and solitary bees. This generalized approach omits important details we will address, such as:
- The actual foraging range of honey bees
- The total standing floral resources or carrying capacity of a landscape
- The seasonal patterns of native bee species activity
- Honey bee pollen and nectar needs.
- The way different bee species use different flowers
A key component when estimating the impact of honey bees on native bees is the foraging range of a honey bee colony. If the range is large, the implication is that a single honey bee colony will remove the pollen and nectar over a very large area, impacting more native bees. Cane and Tependino cite studies from temperate forests to between 1–1.3 miles. A popular article published in a Portland paper suggested the distance could be up to 5 miles.
Some urban boulevards contain high densities of flowering trees and shrubs, which are packed with thousands to hundreds of thousands of flowers. Honey bees respond to this abundance of forage by restricting their foraging to within a few city blocks.
The discrepancy between flight ranges is due to availability of honey bee forage within an area. Some urban boulevards contain high densities of flowering trees and shrubs, which are packed with thousands to hundreds of thousands of flowers.
Honey bees respond to this abundance of forage by restricting their foraging to within a few city blocks. A study of urban honey bee foraging patterns revealed that 78-92% of honey bee foraging trips from the colony are within 0.31–0.75 miles, respectively, even though they can travel farther. The study observed that honey bee foraging range can decrease further when nectar and pollen are abundant but can also expand during months when nectar and pollen become scarce.
During periods of abundant pollen and nectar, the carrying capacity for bees may far exceed that of the honey bees and native bees living in the area. A great example of this comes from a study of the mass blooms of creosote bush (Larrea tridentata) in the deserts of Nevada, Arizona and New Mexico. There are many native bees that specialize on creosote bush, and it is a key native plant for bees in these highly biodiverse desert ecosystems.
The researchers examined the pollen, which remained unharvested by bees, and related it to the number of honey bees foraging at the sites. Honey bees outnumbered native bees 50-to-1 at some of the sites in the study, but there was still generally more pollen produced than the bees present could harvest.
The patterns of honey bee foraging are not only the result of the availability of nectar and pollen around their colonies, but importantly, reflect differences in the need for those resources across the year. One study, for example, observed that honey bee pollen foraging distance was reduced in the summer relative to the honey bee nectar foraging distance.
Why would honey bees travel less far for pollen in the summer? The pollen is used to raise new honey bees and the researchers interpreted these results as reflecting a reduced need for pollen as colony growth begins to slow. An ongoing study at Oregon State University confirms these sharp declines in honey bee colony pollen intake beginning in July for the Willamette Valley.
While pollen and nectar resources vary seasonally in the landscape, they are finite. What if there are too many bees in a landscape with too few resources? One answer to this question comes from a recent study comparing honey bee and native bee competition in two extreme systems in California: wildflower plantings in the highly agricultural Central Valley, and montane meadows in the Sierra Nevada mountains.
The two areas have very different densities of honey bees: the agricultural areas are dense with colonies for crop pollination and the montane meadows have no honey bee populations. The researchers had to move colonies into the Sierra Nevada mountains to be able to measure the impact of honey bees.
Predictably, the available nectar and pollen decreased as honey bee foraging intensified, but remarkably, the native bees tended to switch the plants they were visiting in response to the competition. In the Sierra Nevadas, bumble bees began to specialize on flowers they had previously had no marked preference for. In contrast, in the Central Valley, most native bees became less specialized.
Different bee species do not consider all flowering plants the same. Honey bees prefer certain plants that other bees do not.
The key point of the study from California is that different bee species do not consider all flowering plants the same. Honey bees prefer certain plants that other bees do not. You can observe this for yourself in your garden: In late summer you will see honey bees foraging for nectar on plants in the mint family, like lavender (Lavandula angustifolia), oregano (Origanum vulgare) and Russian sage (Perovskia atriplicifolia).
If you look to some of the composites, like black-eyed Susan (Rudbeckia hirta) or purple coneflower (Echinacea purpurea), honey bees will be rarer while there will be an abundance of composite specialists like sunflower bees (genus Melissodes). Additionally, on some plants like lavender, native bumble bees can outcompete honey bees.
This evidence shows that the method of simply adding up the amount of pollen and nectar a honey bee colony collects and subsequently using that as proof of negative impacts of competition is insufficient. Bees and plants have a long evolutionary relationship that has resulted in a multitude of strategies employed each time a bee departs on a foraging trip and decides what flower to visit.
As the California study demonstrated, increased competition may cause bee species to switch their foraging patterns, resulting in little impact on their overall reproductive success. This is supported by a review of 78 studies on managed versus wild bee competition.
Only half of the studies pointed to a negative impact of competition, and most of the negative impacts were studies where wild bees changed their visitation rate on certain flowers. It has yet to be demonstrated how competition may result in a long-term change in the composition of bee species in an environment.
Do honey bees pollinate exotic plants at the expense of native plants?
A second major concern around beekeeping is that honey bees differentially visit plants that are weeds, allowing these plants to overwhelm an ecosystem with seeds or fruit, thereby replacing the native plants. Many weedy plants such as thistles (Cirsium spp.), knapweeds (Centaurea spp.) and Himalayan blackberry (Rubus armeniacus) require bee visits to propagate. But are honey bees the predominant pollinators of these plants?
Measuring the outcome of a bee visit to a flower is not as straightforward as it seems. Some bee species are highly effective at removing pollen from a plant, but not so good at depositing it, resulting in poor pollination. In other situations, a bee may deposit more pollen per flower, but this does not translate into more seeds or fruit. In fact, it is quite difficult to do studies to confirm either negative or positive effects of the visits of different bee species on exotic and native plant communities.
A review of 47 published studies suggests the impacts of honey bees on exotic compared to native plants is split, with a similar number of studies showing the benefits of honey bee visits to native plants as studies showing benefits to exotic plants. While honey bees may not be as effective at transferring pollen to native plants, for some native plants, including critically endangered plants such as Florida’s Lakela’s mint (Dicerandra immaculata), honey bees appear to be an important component of their current pollination ecology. For another native plant, small camas (Camassia quamash), a study observed that honey bee visits had slightly negative impact on seed production.
When considering the impact of honey bees on invasive weeds, it is important to keep in mind that the exclusion of honey bees from an area could result in these plants still being pollinated by native bees.
It is important to note that honey bees are not the only visitors of weedy plants. Many native bees also visit these plants, but there have been even fewer studies on the impact of native species on the reproduction of weedy exotic plants.
When considering the impact of honey bees on invasive weeds, it is important to keep in mind that the exclusion of honey bees from an area could result in these plants still being pollinated by native bees.
For example, the work of the Oregon Bee Atlas shows that there is a diverse array of native bees that depend on invasive weeds from the genus Centaurea, which includes noxious weeds like yellow starthistle (Centaurea solstitialis) and spotted knapweed (Centaurea stoebe).
Himalayan blackberry (Rubus armeniacus) is another example of a weedy exotic plant that is widely loved by native bees, including one of our most prolific small carpenter bees (Ceratina acantha) that not only visits the flowers but also nests in old canes of Himalayan blackberry.
Consequently, when considering the impact of honey bees on invasive weeds, it is important to keep in mind that the exclusion of honey bees from an area could result in these plants still being pollinated by native bees.
Are honey bees spreading pathogens and parasites to native bees?
The final area to address has been the impact of honey bee diseases and parasites on native bee populations. Notably, research in this area does not focus on the most devastating parasite of honey bees, the Varroa mite, which is restricted to the genus that honey bees belong to (Apis). Rather, research has focused on viruses and microbial parasites that are found in honey bee colonies. The bulk of this research has looked at disease spread from honey bees to the closest relative of honey bees in Oregon — bumble bees — but more recent work has found diseases from honey bees to be present in other bee and wasp species.
The research into disease transfer relies on sensitive genetic methods to detect fungi, bacteria, or viruses in insect specimens. By matching the disease-causing organisms detected in honey bees with those found among other insects in the area, researchers can map how these diseases are potentially being transferred. However, this approach has inherent limitations and flaws.
Firstly, the detection of disease organisms shared between honey bees and native bee species does not prove they are harmful to native bee species. Honey bee research has long established that many detectable viruses have very little impact on individual bees or the colony, and similarly, few studies have documented the negative impacts of these same organisms on native bees.
Secondly, most studies that observe native bees carrying the same diseases as honey bees cannot definitively establish the direction in which the disease was transferred.
It is unclear if the disease is moving from honey bees to native bees, or the reverse.
Consequently, it is unclear if the disease is moving from honey bees to native bees, or the reverse. In the few cases when the direction of disease transfer has been established, it cannot be determined whether the disease can be maintained in the bee species receiving the disease or whether it relies on being continually reinfected from the original host bee species. Ultimately, a disease that cannot reproduce and/or spread in a new host bee species is a dead end.
Although the extent, direction and impact of disease transfer among bee species remain unclear, beekeepers have some control over parasites and diseases in their colonies. Using various management practices, including treatments, diseases can be maintained at low levels, reducing the potential for inter-species transfer. Effective honey bee pest management practices may not only improve the health of honey bees but could lessen potential transfer to native bees.
Such disease management can also be extended to other managed bee species. For example, there is some evidence that honey bees may not be the biggest concern when it comes to disease transfer to native bumble bees. Bumble bees are reared commercially to pollinate greenhouse vegetables and berries. Research has shown that disease levels in native bumble bees are greatest in the vicinity of these commercial bumble bee colonies.
These commercial colonies can also be a significant source of mortality for emerging native queens, who unwittingly are attracted to the entrances of these commercial colonies, where they are frequently killed. Nevertheless, as with honey bees, there are measures that commercial bumble bee producers can and should take to minimize transfer of diseases and parasites to native bumble bees.
Are native bees in urban settings at risk of going extinct?
The subtle and contextual impacts of honey bees on native bees needs to be considered alongside the fact that the native bees in Oregon’s large cities are common and not considered under any threat of extinction. Many of these native bees can be found across most northern U.S. cities.
In contrast, the bees in Oregon that are rare and potentially under threat are not found in either urban areas or even areas where commercial beekeeping is centered. The “hotspots” that host Oregon’s rare bees are chiefly in the high desert, alpine areas and in places with very distinct plant communities, such as those in the serpentine soils of the Cascade-Siskiyous. Consequently, the threat for urban beekeeping activities to result in the extinction of native bees in Oregon is highly unlikely.
Master Melittologists collected around 70 species of bees from 22 genera in Multonomah County between 2018 and 2023.
To illustrate the difference between bees in urban areas versus those in some of Oregon’s bee hotspots, let’s turn to the emerging findings from the Oregon Bee Atlas. An urban center like Multnomah County has an impressive array of bees for an urban center. Master Melittologists collected around 70 species of bees from 22 genera in the county between 2018 and 2023.
In contrast, while collecting a similar number of native bee specimens from the Steens Cooperative Management Area, they found almost double the number of species (121 species) and with 45% more genus-level diversity (32 genera). Additionally, unlike Multnomah County where the bees are known and well recorded, volunteers continually find new bee records for the state when they visit the Steens. In fact, there are bees found in the Steens that have only been observed a handful of times in history.
Master Melittologists are hard at work locating these biodiversity hotspots and make them available to the public through the Oregon Bee Atlas' Melittoflora. Some may argue for restricting beekeeping in some of Oregon’s native bee hotspots, but the Oregon Bee Atlas has shown that these hotspots are largely in areas not conducive to beekeeping.
Is mason and leafcutting bee culture an impact-free alternative to urban beekeeping?
Many Oregonians enjoy raising the native blue orchard bee (Osmia lignaria) in the spring or the exotic alfalfa leafcutting bee (Megachile rotundata) during the summer. These bees require far less work to manage compared to honey bees and can provide excellent backyard pollination. While they do not make honey, they are fascinating to observe and provide a great introduction into solitary bee biology.
Like keeping honey bees, keeping orchard or leafcutting bees requires attention and management to reduce negative impacts. One problem is that there are exotic Asian and European orchard bee species that are difficult to tell apart from native species at the cocoon stage. Care needs to be taken to purchase cocoons from producers without exotic species in their supply chain. People who have these exotic bees in their backyards should not share their cocoons with people in areas where these bees have not yet spread.
The potential impact of Asian and European exotic orchard bees can be significant; one long-term study in the eastern United States has observed the expansion of certain exotic orchard bees coincides with the decline of native orchard bees.
Moreover, there are several diseases and parasites that can directly transfer to wild populations that must be managed on an annual basis. Fortunately, there are ways to minimize these impacts, and anyone interested in culturing these bees can take a class with Oregon State University Extension Master Gardener™ program.
How to 'save the bees' in Oregon?
About a decade ago, the slogan “save the bees” was synonymous with public concern over the heavy losses of honey bee colonies in 2006-2007. These honey bee colony losses — then referred to as Colony Collapse Disorder — also created much-needed public awareness about native bees. But honey bees were never in danger of going extinct, and subsequently, some native bees have been federally designated as either threatened or endangered.
In 2025, there was again exceptional losses to commercial honey bee colonies. With more people aware of the differences between honey bees and native bees, it might be less clear how to go about “saving the bees.”
Beekeeper organizations have been at the forefront of initiatives to increase habitat for bees in general, including the “Bee and Butterfly Habitat Fund” and the “Seeds for Bees” program.
One slogan that has been widely used to convey the sentiment that too much support has been given to beekeeping at the expense of native bee conservation is: "You wouldn't keep a chicken to save a sage-grouse, so why save a honey bee to save a native bee?"
The analogy breaks down immediately when it becomes clear that unlike backyard chicken enthusiasts who may not be at a higher likelihood of supporting sage-grouse management than the average person, many beekeepers are staunch supporters of native bee conservation. In fact, several members of the Oregon Master Beekeepers are also highly productive Master Melittologists.
This reflects a long tradition at Oregon State of faculty who have both served apiculture and native bee conservation, starting with Herman Scullen, who started the apiculture program at OSU and first documented many of the state’s rare native bee and butterflies. In addition, beekeeper organizations have been at the forefront of initiatives to increase habitat for bees in general, including the “Bee and Butterfly Habitat Fund” and the “Seeds for Bees” program.
Finally, beekeepers have been key in working with growers and regulators to reduce pesticide exposure of bees during crop bloom. Beekeepers are critical advocates for native bee conservation and are part of any comprehensive strategy for bee protection in Oregon.
Increasing bee habitat
Maintaining, enhancing, and increasing habitat for bees in Oregon is a complicated issue that could be better coordinated. Plants that are important for honey bees and other long-tongued social bees, like bumble bees, are often relatively inexpensive and easy to grow. Having more of this habitat in urban areas and agricultural areas will help serve both honey bees and our common native bees, thereby reducing competition and promoting bee health.
Shrubs and forbs from the bean (Fabaceae) or mint families (Lamiaceae) are great choices and include clovers, vetches, trefoils, lavender, sages and oregano. Also, there are many excellent summer blooming trees that honey bees and common native bees thrive on, such as American basswood (Tilia americana) and tulip tree (Liriodendron tulipifera).
Growing native plants in gardens is also a great strategy. There are great resources from Oregon State's Garden Ecology Lab on how to incorporate native plants into your gardens. The lab’s research has identified native plants that attract a wide range of native bees, as well as exotic garden plants that are primarily are visited by honey bees. Its research has made a strong case for how choosing native plants can provide a wide range of other benefits, including attracting other beneficial insects and reducing garden water use.
Supporting bee biodiversity 'hot spots'
We also need to look beyond our backyards. The plants used by rarer bees, particularly those that specialize on plants of specific family or genus, are part of intact native plant communities that are difficult to create from scratch and often far from urban areas. Creating these habitats can be a massive undertaking involving years of invasive weed control, propagation of seeds from plants that are difficult to cultivate, and costly ongoing maintenance.
Efforts need to be made to identify the key plant communities in the state that currently serve as bee biodiversity “hot spots” and to put effort into maintaining these lands before they are damaged or degraded. Land trusts and state and federal lands often have intact plant communities that support some of the rarer bees of our state. Their efforts should be supported.
To make progress we need to stop thinking of a one-size-fits all approach to “saving the bees.”
The Oregon Bee Atlas is also hard at work identifying the state’s hotspots to help facilitate this work and communicating the key plants for bees to restoration professionals through the Oregon Bee Atlas’ Melittoflora tool.
Conflicts over which bee to “save” are misguided. We should coordinate efforts across the state to match habitat restoration to regional priorities. In urban and agricultural areas, the emphasis should be on honey bees and common native bees. In “hotspots” we should be putting our resources to maintaining those difficult-to-replace native plant communities that rare bees depend on. To make progress we need to stop thinking of a one-size-fits all approach to “saving the bees.”
References
Almeida, E.A., Bossert, S., Danforth, B.N., Porto, D.S., Freitas, F.V., Davis, C.C., Murray, E.A., Blaimer, B.B., Spasojevic, T., Ströher, P.R. and Orr, M.C., 2023. The evolutionary history of bees in time and space. Current Biology, 33(16), pp.3409-3422.
Balfour, N.J., Garbuzov, M. and Ratnieks, F.L., 2013. Longer tongues and swifter handling: why do more bumble bees (Bombus spp.) than honey bees (Apis mellifera) forage on lavender (Lavandulaspp.)? Ecological Entomology, 38(4), pp.323-329.
Best, L.R., Marshall, C.J. and Red-Laird, S., 2019. Confirmed presence of the squash bee, Peponapis pruinosa (Say, 1837) in the state of Oregon and specimen-based observational records of Peponapis (Say, 1837)(Hymenoptera: Anthophila) in the Oregon State Arthropod Collection. Catalog: Oregon State Arthropod Collection, 3(3).
Cane, J.H. and Tepedino, V.J., 2017. Gauging the effect of honey bee pollen collection on native bee communities. Conservation Letters, 10(2), pp.205-210.
Couvillon, M.J., Riddell Pearce, F.C., Accleton, C., Fensome, K.A., Quah, S.K., Taylor, E.L. and Ratnieks, F.L., 2015. Honey bee foraging distance depends on month and forage type. Apidologie, 46, pp.61-70.
Debnam, S., Saez, A., Aizen, M.A. and Callaway, R.M., 2021. Exotic insect pollinators and native pollination systems. Plant Ecology, 222(9), pp.1075-1088.
Deutsch, K.R., Graham, J.R., Boncristiani, H.F., Bustamante, T., Mortensen, A.N., Schmehl, D.R., Wedde, A.E., Lopez, D.L., Evans, J.D. and Ellis, J.D., 2023. Widespread distribution of honey bee-associated pathogens in native bees and wasps: trends in pathogen prevalence and co-occurrence. Journal of Invertebrate Pathology, 200, p.107973.
Getz, M.P., Best, L.R., Melathopoulos, A.P. and Warren, T.L., 2024. The establishment and potential spread of Osmia cornuta (Hymenoptera: Megachilidae) in North America. Environmental Entomology, 53(6), pp.1147-1156.
Geldmann, J. and González-Varo, J.P., 2018. Conserving honey bees does not help wildlife. Science, 359(6374), pp.392-393.
Garbuzov, M., Schürch, R. and Ratnieks, F.L., 2015. Eating locally: dance decoding demonstrates that urban honey bees in Brighton, UK, forage mainly in the surrounding urban area. Urban Ecosystems, 18, pp.411-418.
Kephart, H., 2025. Should Portland ban backyard beekeeping. Willamette Weekly, May 7 issue. pp. 11-15.
Lamas, Z., Rinkevich, F., Garavito, A., Shaulis, A., Boncristiani, D., Hill, E., Chen, Y.P. and Evans, J.D., 2025. Viruses and vectors tied to honey bee colony losses. bioRxiv, pp.2025-05.
LeCroy, K.A., Savoy-Burke, G., Carr, D.E., Delaney, D.A. and Roulston, T.A.H., 2020. Decline of six native mason bee species following the arrival of an exotic congener. Scientific Reports, 10(1), p.18745.
Mallinger, R.E., Gaines-Day, H.R. and Gratton, C., 2017. Do managed bees have negative effects on wild bees? A systematic review of the literature. PloS one, 12(12), p.e0189268.
Minckley, R.L., Cane, J.H., Kervin, L. and Yanega, D., 2003. Biological impediments to measures of competition among introduced honey bees and desert bees (Hymenoptera: Apiformes). Journal of the Kansas Entomological Society, pp.306-319.
Miller, O., Hale, C., Richardson, L., Sossa, D., Iverson, A., McArt, S., Poveda, K. and Grab, H., 2023. Commercial Bombus impatiens colonies function as ecological traps for wild queens. Journal of Applied Ecology, 60(4), pp.592-600.
Otterstatter, M.C. and Thomson, J.D., 2008. Does pathogen spillover from commercially reared bumble bees threaten wild pollinators? PloS one, 3(7), p.e2771.
Page, M.L. and Williams, N.M., 2023. Evidence of exploitative competition between honey bees and native bees in two California landscapes. Journal of Animal Ecology, 92(9), pp.1802-1814.
Page, M.L. and Williams, N.M., 2023. Honey bee introductions displace native bees and decrease pollination of a native wildflower. Ecology, 104(2), p.e3939.
Richardson, M.L., Keathley, C.P. and Peterson, C.L., 2016. Breeding system of the critically endangered Lakela’s Mint and influence of plant height on pollinators and seed output. Population Ecology, 58, pp.277-284.
Steele, S. and Masta, S.E., 2023. Nest structure of Pseudoanthidium nanum Mocsáry, 1880 (Hymenoptera: Megachilidae: Anthidiini), and additional records of this newly introduced bee in the Pacific Northwest. The Pan-Pacific Entomologist, 99(4), pp.283-288.
Williams, N.M., Minckley, R.L. and Silveira, F.A., 2001. Variation in native bee faunas and its implications for detecting community changes. Conservation Ecology, 5(1).
