Category Archives: bees

The Ethics, Politics, and Science of Lethal Insect Sampling

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A version of this blog post was written for the Hardy Plant Society of Oregon (HPSO) Quarterly Magazine, and was greatly improved by comments and feedback from the HPSO team of editors.

I had been to my mom’s hometown of Bagamanoc many times, but never before as a budding entomologist. In 1993, I packed my bags with the many tools used to collect and curate insects: glassine envelopes to store and sort butterflies, insect pins and boxes, a pinning block, and nets. Once on the ground in this rural region of the tropics, I set out to catch and kill new specimens for my personal insect collection. My prized find was a large birdwing butterfly, with black and red markings and wingspan of more than 6 inches: Atrophaneura semperi. I nearly vibrated with excitement as I caught her in my net. I carefully pulled her out and held her between my thumb and forefinger, so that I could pinch her thorax and break her flight muscles; a trick that was passed down to me by more experienced entomologists. This would ensure that she could no longer move, an activity that might scrape off scales or tear her wings. Pristine specimens are the standard for insect collections.

A large, red and black Philippine Batwing Butterfly. You can see a hand holding the butterfly's wings.
Philippine Batwing Butterfly. Photo from iNaturalist. © LARKSPUR ALFORQUE, some rights reserved (CC-BY-NC)

By the time I boarded a plane to return home, my prized find had been decimated. Ants had found her, and eaten her abdomen. I was crestfallen and ashamed that I had killed her. Since that time, I largely stopped collecting insects for my personal collection. I limit my collection to two taxa (longhorned beetles and metallic wood boring beetles), to keep from killing and pinning every insect that I see. But I have been involved in the lethal collection of many insect specimens for my work, and it is not without the occasional pangs of guilt.

A recent news story profiled Master Gardener volunteers who had collected 25,000 bees in Pennsylvania to further scientific understanding of wild bee abundance and diversity in the state.1 As the story was shared on social media, the comments and concerns related to lethal sampling accumulated: why was it necessary to kill the bees we are supposed to be helping?

In this article, I briefly examine the science, politics, and ethics of lethal sampling.

The Science

I know of only one study that has directly examined the impact of repeated, lethal sampling on insect communities.2 In this study, the authors sampled wild bees every two weeks throughout a season, or once per season. They found no effect of repeated sampling on any of the response variables they measured, including bee abundance, species richness, or community composition. They suggest that density-dependent competitive release may explain their results: decreased survivorship by some is compensated by increased fecundity from others. In essence, as you remove bees from the community, it reduces the intensity of competition and allows surviving bees to produce more offspring than they would have been able to if they had to compete with other bees for resources.

Lethal sampling has long been the rule in studies of insect biodiversity. In homage to the “lock and key hypothesis,” which suggests that genital morphology acts as a reproductive barrier that ultimately defines a species, identifying an insect to species may mean dissecting out genitalia for microscopic examination. In fact, there is a piece of equipment that some entomologists use, that is designed to inflate and harden insect genitalia, called a phalloblaster or vesica everter. This penis pump for insects cost $2,727 in 1997.

A shift away from lethal sampling has been happening for quite some time, particularly for butterflies and other large insects that can be identified by sight. On iNaturalist, many insects are identified to species by combining advances in machine learning and computer vision with crowd-sourced verifications from the iNaturalist community. The platform has led to the discovery and rediscovery of multiple insect species.3, 4

A few of the 2,691 specimens collected for a recent study of garden bee biodiversity. Photo credit: Gail Langellotto.

The Politics

Insects are generally exempt from regulatory oversight. But recent stories of insect declines and the emergence and growth of the insect farming industry has led at least one law school to teach a course on insect law. Institutional Animal Care and Use Committees (IACUC) govern the ethical care of animals used in research studies, but exempts invertebrates from oversight, except for cephalopods (octopus, squid and cuttlefish).

Few laws govern the collection of insect specimens. However, in the state of Washington, insects are classified as wildlife. Permits are required to collect insects for scientific study. This has complicated the launch of the Washington Bee Atlas, run by the Washington Department of Agriculture, which must secure permits from the Washington Department of Fish and Wildlife for every bee collected.

The Ethics

The cephalopod exemption to IACUC oversight is notable, and is based on the recognition that cephalopods are sentient, self-aware, and capable of feeling or fearing pain. Insects don’t have a brain, per se. Instead, they have three clusters of nerve fibers, which form the supraesophageal ganglion. This fact has sometimes been used to argue that insects can’t feel pain, but reviews of recent studies suggest that there is evidence that some insect adults may feel pain,5 and that some may feel emotional states such as stress.6

Another high-profile study found evidence that bumblebees play.7 Play is classified as an activity that does not result in an obvious reward or adaptive outcome, among other criteria. In this study, researchers documented bumblebees interacting with balls in ways that satisfy the criteria for play. The bees received no reward for this behavior. As in many other animals, younger bees played more often than older bees. If insects are sentient, the field of entomology would undergo a revolution of practice.

Conclusion

Insects are so diverse. Many have yet to be discovered and described, and many others look remarkably similar. The only way to identify most insects to species is to have a physical specimen in hand that you can manipulate and examine under a microscope. And it’s notable that a landmark study of insect declines over 27 years used non-selective Malaise traps to enable the capture and counting of what must be tens of thousands of insects.8 It is extremely difficult to study many questions of insect ecology without lethal sampling.

But scientists are increasingly using and improving nonlethal methods in entomology,9 including the use of DNA barcoding, catch and release, and camera traps. Because the study of insects has largely been exempt from regulatory oversight, most entomologists have yet to reflect on the moral considerations of catching and killing insects. However, as we learn more about insect cognition, the time may be coming to carefully weigh the costs and benefits of lethal collection methods and to invest in technologies that advance the use of non-lethal options.

Aa solar-powered camera trap, to study insect visits to an artificial flower platform. On a single pole is mounted (from top to bottom) a solar panel, camera in protective white housing, and yellow flower platform.
An example of a solar-powered and open sourced camera trap, to study insect visits to an artificial flower platform. Photo by Maximilian Sittinger. (CC-BY-SA-4.0).

1Stimpston, Ashley. 2024. Twenty master gardeners have collected 25,000 bees. Here’s why. The Washington Post (October 24, 2024).

2Gezon, Zachariah J. et al. 2015. The effect of repeated, lethal sampling on wild bee abundance and diversity. Methods in Ecology and Evolution, 6(9): 1044-1054.

3Tugwell, James, Masashi and Gaston, Kevin J. 2024. Sixteen insect species photographed for the first time by citizen scientist. ABC News, Australia (October 19, 2024).

4Mesaglio, Thomas. 2021. First known photographs of living specimens: the power of iNaturalist for recording rare tropical butterflies. Journal of Insect Conservation, 25: 905-911.

5Gibbons, M. et al. 2022. Can insects feel pain? A review of the neural and behavioral evidence. Advances in Insect Physiology, 63: 155-229.

6Lambert, H. et al. 2021. Wouldn’t hurt a fly? A review of insect cognition and sentience in relation to their use as food and feed. Applied Animal Behavior Science, 243: 105432.

7Galpayage Dona, Hiruni Samadi et al. 2022. Do bumblebees play? Animal Behavior, 194: 239-251.

8Hallman, Caspar A. et al. 2017. More than 75 percent decline over 27 years in total flying insect biomass in protected areas. PLOS One, 12(10): e0185809.

9Lovei, Gabor L. and Ferrante, Marco. 2024. The use and prospects of nonlethal methods in entomology. Annual Review of Entomology, 69: 183-198.

Queer Entomology

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On the last day of pride month, I read an article that brought me to tears: Can Entomology Emerge as a Role Model Field of Study for LGBTQ+ Inclusion and Visibility? by Michael C. Cavallaro. This year has been extremely difficult for the LGBTQ+ community, and to read about the successes and progress made in my field towards LGBTQ+ inclusion warmed my heart and gave me hope for my fellow queer bug lovers.

Before we dive in to the article, I want to share why this topic is important to me. I identify as a queer entomologist in two ways: 1) I am queer and I am an entomologist, and 2) I am interested in the ways that entomology expands and defies western understanding and expression of gender. The natural world, especially insects, teaches us that queerness is inherently natural and expressed in diverse ways.

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Image description: An intersex bee from the genus Agapostemon. The right side presents characteristics that typify a female Agapostemon: green metallic abdomen, robust legs with pollen carrying hairs, shorter, thicker antennal segments. The left side presents male characteristics, including a yellow and black striped abdomen, yellow legs with fewer hairs, and elongated antennal segments.

Cavallaro begins the article discussing “Shared Traits: Entomologists and LGBTQ+ Folks” by Rae Olsson, which mirrors many conversations I have had with my fellow queer entomologists. Us folks who grow up chasing, collecting, and admiring insects tend to be viewed as weird, odd, or even outcasts. Queer folks are often far too familiar with the feeling of being marginalized, othered, and at odds with society. But, there is an odd comfort in knowing that you are a weirdo studying something weird.

The article continues, noting the advances that ESA (The Entomological Society of America) has made in providing an inclusive environment for LGBTQ+ folks and elevating their voices. We have seen these advances in the form of inviting people to include their pronouns on the annual event badges, introducing symposia on Diversity, Equity and Inclusion (DEI) issues, and removing states with anti-LGBTQ+ laws from potential future meeting locations. He also points out recently identified insects that have been bestowed names of queer icons, which I wrote about during last year’s pollinator week post.

IMAGE DESCRIPTION: A Cowpea weevil, which has long antennae and brown and white spots on its elytra. female cowpea weevils are known to mount other female cowpea weevils. Photo © Gene H on iNaturalist.

Cavallaro reports that 7.2% percent of ESA members have identified themselves as LGBTQ+, which reflects the U.S. national average. He notes that STEM still has many barriers to overcome as it is “rooted in a competitive and heteronormative culture” and “workspaces for queer-spectrum STEM professionals and students can be unsupportive and exclusionary.” Both STEM and entomology still have a long way to go in terms of acceptance, encouragement, and representation of queer folks.

As someone who attended a prestigious field entomology program and was called a “disney princess” on the first day, I can attest to the flippancy with which queer folks and femme-presenting folks are often treated in professional entomological spaces. It is, however, validating to witness the largest entomological organization in the U.S. taking the time to address, welcome, and better their ability to support their LGBTQ+ membership.

Petal-cutting Bees!

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A study of leafcutter bees and a PNW native flower, through the lens of iNaturalist.

The Clarkia Project team: Mallory Mead, Jen Hayes, Sarah Erskine, and Ali Filipovic

If you are a subscriber to our blog, you have likely seen our photos and videos of one of our favorite plant-pollinator interactions: the petals of Farewell-to-Spring (Clarkia amoena) being harvested by leafcutter bees!

After observing this eccentric harvest behavior in the research garden, we got curious about the bees behind the petal-nest craft, and how we could study this interaction further.

Leafcutter bee mid-petal-harvest! Photo by Devon Johnson.
Crescent-shaped petal-cuts left behind by leafcutter bees.

iNaturalist is a popular community-supported biodiversity database that the Garden Ecology Lab has been experimenting with in recent years. Jen realized that the leafcutter bees’ distinct crescent-shaped mark are visible in many iNaturalist observations of Clarkia amoena. She wondered how we could use the already sizeable iNaturalist database of Clarkia amoena observations to study the interaction over a wider geographic and chronological scale than that of the research garden. Jen and Gail agreed to mentor me in producing an undergraduate research thesis on this subject.

The study’s objective is to use iNaturalist’s data on Clarkia amoena to see if there is a difference in leafcutter bee usage of Clarkia amoena petals based on whether the flower is a native versus a cultivar type, and whether the flower is found in an urban or non-urban environment.

In this process we have found that iNaturalist is easy for anyone to contribute to, but the information it provides is limited compared to the wealth of contextual information gained when being in the actual, living presence of a specimen. So, to get a greater feel for the intricacies of this flower, I embarked on what we called “Ground-Truthing Field Trips” to check out some Clarkia amoena populations in the “real world”.

I went out during peak pollinator season, following the coordinates of recently posted iNaturalist observations. Each specimen I visited was incredibly different from the next. I found the delicate blossoms in natural areas, the borders of farmland, restoration sites, and gardens.

Data from these trips will not be published in my thesis because the contexts are not exactly comparable, and my sampling was exploratory rather than precise. Nonetheless, I gained contextual insight and inspiration watching diverse pollinator assemblages in beautiful meadows of pink.

Mallory at a meadow restoration site near Corvallis with Clarkia amoena and tarweed (Madia elegans).

The field trips have helped us more clearly see through the window of iNaturalist and have informed the methodology we use.

For example, I saw examples of hybridization between two species of Clarkia in a seeded restoration site, and cultivar-hybrid escapees in natural areas. It’s been important to navigate identification of cultivars and hybrids in iNaturalist.

In a restoration prairie seeded with two different Clarkia species, pollinators cross-pollinate them, giving rise to sterile hybrids (Lewis & Raven, 1958). Note the malformed stigma and anthers.

Simultaneously, our field crew recorded petal-cutting behavior on the Clarkia amoena natives and nativars at Jen’s research garden this summer. Below are the three cultivars in the garden, and if you look closely you can see “petal-cuts” which we counted and recorded weekly. We will analyze the difference in leafcutter usage between the cultivars and native type.

‘Aurora’
‘Scarlet’
‘Dwarf White’
This hot pink, stripy Clarkia doesn’t look like either the native or cultivars we had planted!

Clarkia amoena is an annual that reseeds itself effectively, so last year’s seeds gave rise to this season’s blooms. To our surprise, however, Clarkia amoena of all different colors started popping up in our research plots this Spring! Last season’s bees had combined pollen from the garden’s varieties bringing rise to all sorts of intermediate forms.

Clarkia amoena is prone to hybridization between members of the species or cultivars in the same proximity. These intraspecific hybrids are fertile. We seek to explore how cultivar genetics may be moving into natural populations.

Through the winter, our team is working with the iNaturalist data to quantify leafcutter bee petal usage. We expect to share our results in June 2023, so stick around to hear about our findings!

Work Cited:

Lewis, H., & Raven, P. H. (1958). Rapid Evolution in Clarkia. Society for the Study of Evolution, 12(3), 319–336.

What are bees doing right now? Fall Edition

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The sunny days are diminishing as summer rolls into autumn, and as the sun descends, the bees’ flight lulls to rest. Bees sense and respond to light and use the sun to orient themselves and navigate. Along with their two large compound eyes that are used for vision, bees have three simple eyes that sit atop their their heads in a triangular formation. These are called ‘ocelli’ and they sense light.

Originally posted by postgraduate student Hamish Symington, this video shows bees being studied by fellow student Kristina Buch in the Cambridge University Botanic Garden.
Ocelli can be seen atop the head between the compound eyes. Photo of bee from the genus Triepeolus by Mallory Mead.

There is a video circulating the internet of honeybees flying in an enclosure in a laboratory. The video shows the researcher turning off the lights in the enclosure, causing the bees to drop to the ground instantaneously, showing how honeybees will not fly in the absence of light.

We notice similar behavior in the field on days where clouds pass over the sun intermittently. When the sky is bright, our plants bustle with pollinators, and when shadows come over, most bees are suddenly out of sight. It makes sense that as the days get shorter and colder the sight of pollinators will become more and more fleeting!

Some bees are still coming out during the warm October afternoons, and collecting their final energy reserves for the winter. Goldenrod, Douglas’ aster, California poppy, bee balms, and black-eyed Susan, amongst other late blooming pollinator plants are still providing bees with nectar and pollen during this time of transition.

  • Purple Aster and goldenrod in a natural meadow. Photos by Mallory Mead.
  • Goldenrod in meadow.
  • A long horned bee and a sweat bee on black-eyed Susan (Rudbeckia hirta).
  • Metallic green sweat bee on Scabiosa.

During this season, honeybees and bumblebees predominate the landscape, while long-horned bees (genus: Melisoddes), leafcutter bees (genus: Megachile) and sweat bees (family: Halictidae) can still be seen as they finish up resource collection in the Willamette Valley.

Social bees

Honeybees must make enough honey before temperatures drop and they can no longer leave the hive, so you’ll find them foraging for pollen and nectar as late in the season as possible.

In late summer and fall we begin to see an influx of bumblebee queens. During the summer, the queens are busy reproducing in their underground hives, while worker bees take to the landscape. However, near the end of the foraging season, new queens hatch and fly out to find mates and food. You may see bumblebee queens getting their last bits of food energy before overwintering, while the rest of the colony (males and workers) dwindle away.

Black tailed Bumble Bee (Bombus Melanopygus) © Erin Forrester, some rights reserved (CC-BY-NC)

Check out this guide to Bumble Bees of the Western United States to see which Bombus species are found in your region and what time of year they are active.

Solitary Bees

  • Leaf, mud and petal nests are capped and ready for winter! Photos by Mallory Mead.
  • Petal nest in bamboo.

Many solitary bees are finishing their last nests where they’ve laid eggs for the next generation of their species.

If you care for nest boxes in your garden be sure to take appropriate steps to bring your bees indoors and clean their cocoons. Check out the Linn Master Gardener Association Bee Notes email list to receive timely emails about the seasonal steps of caring for mason bees.

When solitary adult bees finish reproducing and nest building, their work is done, so they die off. But small carpenter bees, from the genus Ceratina, are an exception. Ceratina females remain as late into the cold season as they can muster in order to guard their nests.1 These protective mothers fend off predators, pests and parasitoids that try to invade the nests.

Ceratina acantha © vespidmacro, some rights reserved (CC-BY-NC)

This fall, we hope you are able to see some of the last glimpses of bees of the year!

This post concludes our series on what the bees are doing right now! Thank you for taking part in this seasonal journey through the lives of bees in the Willamette Valley.

Source Cited:

1: Danforth, B. N., Minckley, R. L., & Neff, J. L. (2019). The solitary bees: Biology, evolution, conservation. Princeton University Press.

New Summer Game- Pollinator Bingo!

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Summer pollinator Bingo board!

We are entering the heart of summer, with blue skies, rising temperatures, blooming flowers, and growing gardens. As some of us are taking this time to relax in the bounty of our gardens and in whatever shade we can find, our pollinator counterparts are in the middle of their busiest season. The pollinators are out in full force, and it seems almost impossible to turn around in a garden without spotting a new butterfly, bee, or beetle. So for those among us who want to engage even further with the friends visiting our gardens around this time of year, we have the perfect game for you: Pollinator Bingo! 

Our Pollinator Bingo-or should we say BEEngo- is a healthy mix between Bingo and a scavenger hunt! 

Here’s how to play:

  1. Select the Bingo Card you will use 
  2. Download it, or print it out, and get it ready to be filled out 
  3. Keep your eyes open for these visitors in a garden. When you spot a pollinator on your Bingo card, mark that pollinators square. 
  4. Once you fill an entire row (horizontal, vertical or diagonal) you’ve won your BEEngo!  
  5. Extra Credit Challenge: Try to black out the entire card! 

We hope you have fun playing Pollinator Bingo outside, exploring and enjoying the natural world in some way. Good luck BEEngo players! 

Pollinator Bingo Board 1Download
Pollinator Bingo Board 2Download

Below, we included some pollinator spotlights, so you can get to know some of the species on your Bingo card a little better!

Pollinator Bingo Spotlight List:

  1. Tribe Eucerini, Longhorned bee

Eucerini, also known as long-horned bees, are favorites among our lab members. They are the most diverse tribe in the family Apidae, with over 32 genera. These bees are solitary and ground-nesting. What makes them distinct and a lab favorite are the long antennae the males are known for and from which they get their common name. The females are also recognizable, as they have long hairs, known as scopae, on their hind legs, giving them the appearance of wearing very thick pants. 

Photo by Svea Bruslind

2. Species Papilio machaon oregonia, Oregon Swallowtail butterfly 

As with any in the Swallowtail family, Papilio machaon oregonia, or the Oregon Swallowtail, is big, beautiful, and eye-catching. It was officially named Oregon’s state insect on July 16, 1979. It is native to the northwest and is only found in Oregon, Washington, Idaho, and sections of British Columbia. For the purposes of Pollinator Bingo, any Swallowtail will count for its space. Keep an eye out for the Oregon Swallowtail and others, and see how many different species you can find!

Photo by Cara Still

3. Family Syrphidae, Flower Fly 

Hoverflies, flower flies, and syrphid flies are all different names for the flies within the family Syrphidae. Syrphid flies come in a wide variety of sizes and colors, with some that resemble wasps and others that look nearly identical to bees. Most syrphids, however, can be found with some kind of striping on their abdomen.  Syrphids are essential to any garden as they help with pest control and pollination. Some people are surprised that flies are pollinators too, but hopefully, this list can illustrate the wide variety of pollinators out there! 

Photo by Devon Johnson

4. Species Trichodes ornatus, Ornate Checkered beetle 

Trichodes ornatus, or the Ornate Checkered beetle, is an interesting species, as during the early stages of its life, instead of pollinating, it feeds on pollinators. These beetles will lay their eggs on plants such as yarrow, sagebrush, and asters. When these eggs hatch, the larvae attach themselves to a visiting bee, usually a leafcutter bee. They will then be transported to the bee’s nest, where they will eat the provisions left there for the host larvae before eating the host larvae and burrowing into nearby cells to do the same. As an adult, the Ornate Checkered beetle will feed on pollen but will not miss an opportunity to snack on other visiting pollinators when foraging for pollen.

Attribution © LapisOre some rights reserved (CC by lapis_the_mothman iNaturalist user)

5. Species Calypte Anna, Anna’s hummingbird

Calypte Anna or Anna’s hummingbird should be a familiar sight for many of us. This rambunctious bird is a permanent resident along the Pacific Coast, staying year-round through winters instead of engaging in migration as other species of hummingbirds are known to do. Males of Anna’s hummingbird are pretty talkative, often vocalizing with a buzzy song. The males have a brilliant red head with a green body, and the females have similar green plumage, but without the red coloration on their face and neck. 

Attribution © selwynq some rights reserved (CC by selwynq iNaturalist user)

What are bees doing right now? Summer Edition

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Graphic by Jen Hayes

Summer is the main active season for many bee species. After a wet spring in Western Oregon, the sun is out and our world is in bloom!

So what are summer bees up to right now? The main events of the season are…

  • Foraging for nectar and pollen
  • Finding mates and laying eggs
  • Excavating, finding and building nests for offspring.

Adult bees also experience predation by spiders and birds during this time. This Crab Spider caught a female long horned bee in its jaws!

A female long horned bee caught by a crab spider on Douglas’ Aster.

So who exactly is out and about in your garden at this time of year?

Bumblebees and honeybees visibly dominate the landscape throughout the summer, but lean in closer to your flowering plants and you’ll find the smaller sweat bees (family: Halictidae), long horned bees (genera: Melissodes and Eucera), leafcutter bees (genus: Megachile) and small carpenter bees (genus: Ceratina). Although there are many others amid the vast diversity of bee species science is only beginning to understand, these are some common garden visitors. We’ll go through each group and their summer activities.

Notice the two adomenal segments beneath the yellow stripe of this male yellow-faced bumblebee (Bombus vosnesenskii). Photo by Jen Hayes.

The presence of pollen on a bee especially carried in pollen baskets, is a good indicator that the bee is a female. Photo by Jay Stiller-Freeman

Bumblebees: By summertime, most queens have established colonies of workers who do the foraging for the hive, so we see less large queen bumblebees and more smaller workers as the season progresses. Later in the season, queens lay male eggs as well as eggs for the next generation of queens. Male bumblebees take to the landscape in mid to later summer, recognizable by their additional segments on their abdomen, long antennae, and by the fact that they don’t carry pollen like females do. Males do not have stingers, so if you can confidently identify male bumblebees, they are fun to play with while they’re waiting around for new queens with which to mate. You’ll find them sipping on nectar-rich plants like lavender, herbs, asters and heal-all.

Honeybees: Summer is prime time for honeybees! Worker populations are at their peaks; pollen and nectar are flowing. As hive population size rises and available hive space remains static, honeybees may organize a swarm. In this process, the current queen lays new queen eggs and part of the colony joins her to lift off and leave the colony in search of a new cavity to make their home. Swarming is considered a form of colony-level reproduction supporting the idea that honey bee colonies are super organisms. Swarming is common in spring and early summer. Beekeepers add new boxes to hives so prevent their colonies from swarming.

Late summer is mating season for honey bees. Males and new queen eggs are laid and emerge to mate with individuals from other colonies. Honeybees mate in the air at heights ranging between 15 and 60 m1.

A yellow-faced bumble bee and a honey bee sip nectar from lavender. Photo by Devon Johnson.

Sweat bees

Sweat bee on California Poppy ‘White’. Photo by Tyler Sato Spofford.

A halictid dear to our hearts at the Garden Ecology Lab is the metallic green bee (genus: Agapostemon). While females provision nests in the soil, you can find males resting in congregations on flowers in the evening time and early morning!

Sweat bees are one of the most common groups of “small” bees you’ll find in your garden. They forage on a wide variety of plants and come in a wide range of sizes, but most have striped abdomens, and all carry pollen on their hind legs and nest in soil.

Agapostemon virescens male congregation.
A male long horned bee from the genus Eucera on a California Poppy ‘Purple Gleam’. Photo by Jen Hayes.

Long Horned bees

Long horned bees are most active on our research plots in the mid to late summer. I love this group because they are so easy to recognize. Males have antennae that are way longer than other bees’ relative to their bodies. The females, who bear antenna of normal lengths, are still easy to spot because they have long feathery scopa (or hairs) on their hind legs for collecting pollen that they absolutely pack with pollen while foraging.

Long horned bees are sometimes referred to as “sunflower bees” for their love of foraging on sunflowers.

Long horned bees nest in the soil2, so when you see them take it as a reminder to leave some uncovered, undisturbed soil in your garden for these bees to persist!

Notice this female long horn’s feathery pants! Photo by Mallory Mead.
A relatively large small carpenter bee. Photo by Mallory Mead.

Small Carpenter bees

When I point out small carpenter bees (genus: Ceratina), most of my friends can’t believe they are bees. They think they are some kind of flying ant. Their bodies are sleek, and often shimmer with a green or blue reflective gleam.

Small carpenter bees are considered wood excavators as they dig out the pith from dry plant canes for their nests. Ceratina are a unique group in terms of their parenting style. Unlike other solitary bee mothers, Ceratina mothers guard their offspring even after their offspring have developed into adults. Mothers stick around as long as they can until Winter falls.2

Leafcutter bees

Leafcutter bees (genus: Megachile), as their names suggest cut leaves from their host plants! They use these bits of leaves to line their ground and cavity nests, to waterproof and protect their offspring.

Leafcutter bees are from the bee family Megachilidae, a family known for creative nest building. Bees in this family were supposedly able to expand their ranges due to their flexibility in nesting site and material. They’ve been found nesting in wood, porous stones, stems, galls, and even snail shells filling these various cavities with leaves, mud, plant resins, pebbles, straw and even petals2. The fascinating nest building behavior we’ve gotten to witness in the field is petal cutting of Farewell-to-Spring (Clarkia amoena) blooms.

We can track the usage of Farewell-to-Spring petals by leafcutter bees due to the signature crescent shape left behind on the flowers.

Thank you for joining us on this exploration of some of Oregon’s summer bees and what they are currently doing! We will release one more blog post in this series. Be sure to subscribe so you don’t miss the next in the series!

Sources

1: Landscape Analysis of Drone Congregation Areas of the Honey Bee, Apis mellifera by Galindo-Cardona et. al, 2012. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3635128/

2: The Solitary Bees by Bryan N. Danforth, Robert L. Minckley, and John L. Neff. 2019.

What are bees doing right now? Spring edition

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It’s early spring and the trees have begun leafing out. Colorful flowers are springing from the ground, and the landscape is slowly coming to life with insect activity. In this post, I’ll highlight some of Oregon’s ubiquitous spring bees, what they are up to, and how to easily recognize them.

Graphic by Jen Hayes

Queen bumblebees are emerging from their winter burrows under leaf litter and forest duff. They zoom by with boisterous buzzes. Queen bumblebees are sturdy and furry, and can power through wind, rain and cold better than any other type of bee. Queens are much bigger than the workers that will come once the queens find nest sites and begin laying eggs. For now, they work alone, preparing to lay their first set of worker eggs.

If you see (or hear) any queen bumblebees this spring as they scan the sparsely blooming landscape, they are most likely looking for a proper nest site, finding nectar to energize this search, or, if one has already found her nest, she may be collecting pollen to feed her developing worker offspring.

A rain-drenched Yellow-faced bumble bee on Oregon Grape. Photo by Jen Hayes.
A female mason bee has brought bright yellow pollen to her nest. Video by Jen Hayes.

Mason bees (Osmia lignaria) are a cherished Oregon spring bee active from March to early June. Look closely in a bee hotel for a chance to observe mason bees in action!

Male mason bees emerge first from their pupal cocoons. You might see them patrolling bee hotels waiting for a female to chase down. When the females emerge a little later, they mate and then begin their work provisioning nests with pollen balls and eggs. An individual female has a short lifespan living only about 20 days, but in this time, she may provision anywhere from 2 to 7 nest holes each containing many offspring cells.1 Quite the busy bee!

Andrena is a genus of mining bees that are some of the earliest risers when it comes to spring emergence. They are a diverse group of small, furry, ground-nesting bees that are only active for a few weeks out of the year. Andrena are solitary bees, but can be seen foraging and mating in droves on early blooming fruit trees like cherry, apple and pear. Last spring, I watched hundreds swarm this cherry tree to collect nectar and mate.

  • Andrena in cherry tree (captured with magnifying lens). Photo by Mallory Mead
  • Andrena mating pair. Photo by Mallory Mead.

Spring Bee Quick ID:

Now, let’s identify some of the bees you may see out and about on sunny spring days when the wind is low. We’ll start with the most conspicuous group – the bumblebees. Bumblebees are the biggest and the loudest bees on the landscape, covered in a thick coat of fuzz. Here’s how to recognize the 3 most common species of bumblebees you’ll see in the Willamette Valley in early spring.

Bombus vosnesenskii or the “yellow-faced bumblebee” is by far the most common bumblebee in this region. It is recognized by the yellow fuzz on its face and yellow band near the distal end of its abdomen.

B. vosnesenskii foraging on butterfly bush. Photo by Mallory Mead.
B. melanopygus queen foraging on Wartleaf Ceanothus. Photo by Mallory Mead.

Bombus melanopygus, the “black-tailed bumble bee” is another of the earliest Bombus species to emerge. You can identify this bee by the orange band in the middle section of its abdomen!

Bombus mixtus, the “fuzzy-horned bumblebee”, tends to emerge a little later than the previous two species, and has orange hair on its lowest abdominal segments.

B. mixtus flies amid borage plant. Photo by Mallory Mead.

Mason bees can be recognized by their deep iridescent blue-green color, that sparkles in the sun. Males are distinguished from females by their small size and the yellow mustaches found on the front of their faces. Females lack the yellow tufts and are larger than the males but smaller than a honey bee. They carry pollen on the underside of their abdomen which is a trait unique to their bee family, Megachilidae.

Female mason bee. Photo by Jen Hayes.
Male mason bee. Photo by Mallory Mead.

Andrena are a diverse group that are tricky to identify. They can be distinguished from other small, furry bees by the presence of velvety hairs between their eyes and the middle of their face called “facial fovea”.2

Pollen on Andrena bee. Photo by © vespidmacro, some rights reserved (CC-BY-NC)

Facial Fovea. Photo from the ODA Bee Guide

They also carry pollen on their hind legs and on hairs between their abdomen and thorax, which distinguish them from bees in the Megachilidae family.

We hope this little guide will help you experience the native bees in your landscape this spring that make the pollen go round.

Thank you for joining us on this exploration of Oregon’s spring bees and what they are currently doing! We will release two more blog posts in this series, one for each of the four seasons. Blogs will be posted during their prospective seasons, so be sure to subscribe so you don’t miss the next in the series!

What are bees doing right now? Winter Edition ❄️.

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Welcome to the Garden Ecology Lab’s “What are the bees doing” mini-series! This series will extend through the four seasons to shed some light on where bees are in their life cycle and what they may be doing during each of the four seasons. We begin with winter, and an overview of the overwintering and nesting strategies of common groups of bees in the Pacific Northwest.

Graphic by Jen Hayes

As the seasons change, where do all the bees go? Different groups of bees utilize unique strategies to survive the cold of winter. In many cases, bees require cold temperatures to develop properly, and as spring rolls around, they rely on thermal cues to determine when to start their next phase of life.

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We can divide bees into four broad categories based on their strategy to nest and survive the winter. There are the Ground Nesters – who find or dig in the ground to nest and lay eggs, Cavity Nesters – who nest in hollow reeds, canes, or in people’s backyard “bee hotels”, Bumblebees – whose new-born queens burrow into leaf litter, waiting to start a colony in spring…. and then there is the oddball: the European Honey Bees, who are not native to North America, but were brought here along with European colonizers and are now key players in modern agriculture. They do things pretty differently than our native bees, so we’ll start our discussion with them.

The European Honey Bee

European honey bees (Apis mellifera) survive the winter huddling in their hive! They are an example of a social insect and many consider a honey bee hive a superorganism. Fueled by their honey stores, the colony huddles together in a mass to thermoregulate at temperatures between 33 – 36°C (91.4 – 96.8°F).1 I love these words from the American Bee Journal:

 "The honey bee is a cold blooded insect; but the honey bee colony is a warm blooded creature."1

We will see that honey bees are the only bee in our landscape to overwinter socially. The rest go it alone.

Bumblebees

A Bombus californicus queen on Comfrey (Symphytum sp.) in early Spring. Photo by Mallory Mead.

Bumblebees are social bees too, living in natural cavities most often in the ground, but in winter, the members of the colony die off except for the new-born queens. These queens will fly out of the hive on her maiden voyage to mate with a male bumblebee before finding a place to settle and overwinter alone.

Queens find a safe environment often a few inches deep under leaf litter or light soil. As temperatures decrease in Fall and early Winter, the queens do not thermoregulate. Instead, they enter diapause, which is a state of arrested development. An overwintering queen appears frozen in the soil until warmer temperatures wake her again. In the late Winter or Spring she will begin looking for a site to start her own colony.

Cavity Nesting Bees

About 30% of native bees are cavity nesters who build their nests inside cavities in wood or reeds.2 These bees avoid overwintering as adults, and instead, they lay their eggs in cavities and die before the winter temperatures come.

Female cavity nesting bees forage for pollen and nectar and nesting materials in the spring or summer and make balls of pollen and nectar (often called “bee bread”) as food for their offspring!

They lay eggs on the pollen balls, and then proceed to seal off compartments, one for each of the eggs, until the cavity nest is full. These eggs will hatch into larvae that consume the bee bread as winter approaches.

Bee nests in bamboo sticks, indicated by the mud caps at the front of the stakes. Photo by Gail Langellotto
Video by Oliva Honigman.

Here is a video of a small carpenter bee larva eating its bee bread, magnified under a microscope!

Once the larvae finish off their food store, they may spin themselves a cocoon in which they further develop into pupae. Cavity nesters spend the winter developing from pupae to young adults in their cocoons. These developing bees go into a state called torpor to survive the winter, where the bee is inactive and its body temperature drops, but it still goes through critical physiological processes and development.

These bees must experience low Winter temperatures natural to their region to undergo proper development. Mason bees, for example, have lower survival and vital rates when exposed to warm nest temperatures that simulate predicted climate change temperatures for their region.3

Empty mason bee cocoons that were removed from cavities for an experiment, and a newly emerged male mason bee. Photo by Mallory Mead.

Mason bees (genus: Osmia) are cavity nesters that have become well known in garden and agriculture circles in recent years, but many other groups of bees fall into this category too including leafcutter bees (family: Megachilidae), small carpenter bees (genus: Ceratina), large carpenter bees (Genus: Xylocopa), and masked bees (family: Colletidae).

SARE has a great resource on identifying which cavity nester might be nesting in your bee hotel!

A friend of the lab, Olivia Honigman, conducted a brief research project on small carpenter bees in Vermont. Here are some photos from her study that showcase a tiny cavity nesting bee, from the genus Ceratina, nesting in raspberry canes.

  • Ceratina larva in a raspberry cane. Photo by Olivia Honigman.
  • Ceratina larva and pollen ball under a scope. Photo by Olivia Honigman
  • Developing Ceratina pupae. Photo by Olivia Honigman.
  • Ceratina sp. flying into raspberry cane nest. Photo by Olivia Honigman.

Ground Nesting Bees

Last but certainly not least are the ground-nesting bees which make up about 70% of native bee species! Bees from the genera Andrena, Lasioglossum, and Halictus fall into this category.4 Ground-nesters have unassuming nests that are hard to spot, but under the soil, they are putting down bee loaves and laying eggs in a compartmentalized fashion, just like cavity-nesters!

Similarly, adult ground-nesters die after they finish provisioning their nests for their offspring. In the winter, the young bees of the new generation are developing from pupae into adults in their underground nests.

Left: exposed soil revealing tiny holes- could these be bee nests? Top right: A ground-nesting bee pokes its head out of its home. Bottom right: The entrance to a ground-nesting bee’s home. Photos by Gail Langellotto.

Although their nests are modest, some of Oregon’s showstopper bees fall in the ground-nesting category, such as the metallic green sweat bees (Agapostemon).

Metallic green sweat bee on a Clarkia flower. Photo by Mallory Mead.

Long-horned bees from the genera Melisoddes and Eucera also flaunt unique forms with noticeably fluffy, feathery hair on their legs they use for collecting massive volumes of pollen!

A female long-horned bee with dense hairs or scopa on her hind legs. Photo by Mallory Mead
This long-horned bee has “pollen pants” Photo by Mallory Mead.

To invite these bees to your garden, leave patches of earth free from wood mulch and instead mulch with compost! To avoid disturbing ground nests, avoid tilling when possible.4

Here is a great resource from the Xerces Society on how to protect pollinators during the Winter months.

Something remarkable about nesting in the ground is that, depending on nesting depth, ground nesters are more buffered from extreme temperatures than honey bees and cavity nesters whose homes may be in the direct sun. This may be a critical difference when it comes to surviving climate change.

Changing Climatic Norms…

With climate change upon us, native bees have experienced warmer than usual winter temperatures. These conditions may be suboptimal for their development and survival and encourage bees to emerge earlier in the season. Cavity and ground nesting bees require low temperatures with which they have evolved to reach physiological benchmarks for their development, and scientists worry that there will be phenological mismatches between plants and their pollinators in which bees emerge at different times than when their optimal food sources are in bloom as plants and insects will experience novel timing of thermal queues under climate change predictions.5

As bees and other pollinators face a multitude of challenges, we should support our local bees and appreciate them while we can!

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Thank you for joining us on this exploration of what bees are doing during the winter! We will release three more blog posts in this series, one for each of the four seasons. Blogs will be posted during their prospective seasons, so be sure to subscribe so you don’t miss the next in the series!

Top 10 Oregon Native Plants for Pollinators: WEEK 10!!

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The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. Douglas Aster!

The Garden Ecology Lab is releasing a series of plant profiles of the top 10 Oregon native plants for pollinators, based on Aaron Anderson’s 2017-2019 field trials of 23 Oregon native plants. We will feature one plant per week for 10 weeks, this is week 10, which marks the end of our 10-week series! Profiles will include photos, planting information, and will highlight common pollinators of each plant.

Melissodes visits Douglas Aster. Photo by Tyler Spofford.

Plant Facts

  • Scientific Name: Symphyotrichum subspicatum
  • Life Cycle: Perennial
  • Growth Habit: Vigorous spreader, spreads through underground rhizomes
  • Bloom Duration: July-November
  • Hardiness Zone: 6-9
  • Special Traits: Drought tolerant, deer resistant
  • When to plant: Starts can be planted in the spring or early fall.

Pollinator Facts

  • Douglas aster provides both nectar and pollen to its insect visitors.
  • Aaron’s research found three species of long-horned bees (Melissodes robustior, M. lupinus, and M. microstictus) and three species of bees from the family Halictidae (Halictus ligatus, Agapostemon texanus angelicus and A. virescens) to be associated with Douglas aster.
  • Other common visitors to Douglas aster include syrphid flies and northern checkerspot butterflies! Douglas aster may also be a larval host to 8 different month species1.
Photo by © mandamasprime, some rights reserved (CC-BY-NC).

Douglas Aster‘s Native Range in Oregon

Douglas aster is native to Northwestern Oregon and most of the coast.

Maps and legend acquired from the Oregon Flora Project, with Imagery Sourced from Google. Copyright 2022© TerraMetrics

Douglas Aster as a pollinator plant

Douglas aster is native to Western North American with a range extending from Alaska to California. It has an impressive ability to spread and a high volume of flowers that buzz with pollinator activity throughout its long bloom season. Hosting a high abundance and diversity of bee visitors, Douglas aster is a pollinator plant superstar. It is particularly valuable as a late-season pollinator plant, able to provide both nectar and pollen to its visitors when these resources may otherwise be scarce in the landscape.

People often have strong reactions towards Douglas Aster – they either love it, or find it to be “weedy” in appearance. We hope that this highlight may help some people change their opinions about it! We in the Garden Ecology Lab love Douglas Aster for its abundant blooms in varying shades of purple and for its great capacity for supporting wildlife. In the late summer, we love watching the diversity of pollinators bouncing from one flower to the next! Some common visitors to Douglas Aster that we see at Oak Creek Center for Urban Horticulture include bumblebees, green bees, long-horned bees, small sweat bees, and butterflies, including the woodland skipper (pictured below) and the occasional grey hairstreak (Strymon melinus).

Here, we see a woodland skipper (Ochlodes sylvanoides) foraging from Douglas Aster!
Infographics developed by LeAnn Locher, Aaron Anderson, and Gail Langellotto.

Did you know?

By mid to late summer, Douglas aster is quite the frenzied pollinator feeding ground, making the Oak Creek team’s sampling effort always a bit of a challenge. These photos are from 2 years after these plants were established, so you can see just how full these young plants can get when grown in favorable conditions!

At Oak Creek, we started all of our Douglas Aster plots with 4x 4″ pots, planted in the spring of 2020. As you can see in the photos below, they easily filled up their 1×1 meter beds! If you’re worried about Douglas Aster taking over your garden, consider starting with a single plant and observe it over the season to see how it reacts to your garden environment. Aggressive spreaders can be used to fill spaces such as borders with forest edges or along fences where low maintenance plants are key. If you want to contain your asters, consider planting some in a large pot or in an area where you can easily control the spread of their underground rhizomes. The purple flowers contrast beautifully with other late season natives, such as goldenrod and Madia.

Jen standing next to her Douglas Aster experimental plots. Photo by Tyler Spofford.
Tyler vacuum sampling bees off of a Douglas Aster plot. Photo by Jen Hayes.

Photos from the field

  • A yellow-faced Bumblebee visits a Douglas Aster flower
  • A woodland skipper enjoying some nectar
  • The baby Douglas Aster plants we introduced into the field in 2020
  • Douglas Aster still blooming strong on October 3, 2020
  • The native Douglas Aster has beautiful purple rhizomes!
  • Douglas Aster cultivars are even more vigorous, look at all these new shoots we removed from a neighboring plot!
  • Douglas Aster 1 year after planting, with last season’s biomass removed
  • A sweat bee enjoying some pollen!

Thanks for tuning in to the last posting of our Pollinator Plant PR Campaign! We hope you try growing some of these fantastic pollinators plants.

Top 10 Oregon Native Plants for Pollinators: Week 9

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The Garden Ecology Lab’s Pollinator Plant PR Campaign Presents….. California Poppy!

The Garden Ecology Lab is releasing a series of plant profiles of the top 10 Oregon native plants for pollinators, based on Aaron Anderson’s 2017-2019 field trials of 23 Oregon native plants. We will feature one plant per week for 10 weeks, this is week 9! Profiles will include photos, planting information, and will highlight common pollinators of each plant.

Photo by Jen Hayes

Plant Facts

  • Scientific Name: Eschscholzia californica
  • Life Cycle: Annual/Perennial
  • Growth Habit: Clumping, sprawling
  • Bloom Duration: Early Spring to Late Summer depending on seeding date.
  • Hardiness Zone: 7-10
  • Special Traits: Drought-tolerant, deer and rabbit resistant.
  • When to plant: Seed in Fall for a Spring bloom, or seed in Spring for a mid-summer bloom.

Pollinator Facts

  • California poppy only provides pollen to its insect visitors, but provides it in an abundance!
  • Aaron’s study found California poppy to be associated with 4 species of sweat bees: Halictus farinosus, H. tripartitus, Lasioglossum dialictus sp. 5, L. olympiae, and a bumblebee: Bombus vosnesenskii.
  • Other common visitors to California poppy include butterflies, specifically, acmon blue and mormon metalmark.

Sweat bee leaving a California poppy. Photo by Jen Hayes

California Poppy’s Native Range in Oregon

Oregon's populations of California poppy are primarily found in the Willamette Valley and the Klamath Mountains as well as some parts of the Columbia River Gorge and the Coast Range.

Maps and legend acquired from the Oregon Flora Project, with Imagery Sourced from Google. Copyright 2021© TerraMetrics

California poppy as a pollinator plant

California poppy’s range extends from Washington to northwest Baja California and east towards Arizona and southwest New Mexico. A popular flower for roadside plantings, California poppy survives well in average to poor soil that is well-draining. It survives mild-winters as an herbaceous perennial and reseeds itself readily. California poppy is an all-around easy pollinator plant to grow, and growing it pays off, as it attracts an incredible diversity and abundance of bees with its remarkable volumes of pollen.

Infographics developed by LeAnn Locher, Aaron Anderson, and Gail Langellotto.

Did you know?

California poppy’s petals are responsive to light! In the absence of light (at night and on cloudy days) petals spiral around each other and tighten to a close. In the presence of light, cells in the petals expand in response to the plant growth hormone auxin. This mechanism opens the petals allowing pollinators to access the flower’s pollen — although in the field we watch impatient bumblebees force their way into closed California poppy flowers to get to the pollen anyways.

Petals close tight during the night and remain so on overcast days. Photo by iNaturalist user metacom CC some rights reserved
Poppies in various stages of opening and poppy buds enclosed in pinkish-green calyxes. Photo by iNaturalist user Daniel Das CC some rights reserved

Photos from the field

  • Sweat bee traversing stamen. Photo by Jen Hayes
  • The underside of a sweat bee with pollen on its abdomen and hind legs. Photo by Jen Hayes
  • Photo by iNaturalist user baileylemkau CC Some rights reserved.
  • Jen’s California poppy research plot. Photo by Jen Hayes

Tune in next week for the next edition of our Pollinator Plant PR Campaign.