What are bees doing right now? Fall Edition

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.

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

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!

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! 

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)

Pollinator Week 2022

Happy pollinator week and first official week of summer! ☀️🐝🦋

Pollinator week is an annual celebration in June to emphasize the importance of pollinators and their health, started by the Pollinator Partnership. To celebrate pollinator week, we’re going to share some information with you about a few of our favorite pollinators and a few others deserving recognition. June is also Pride Month, so we are going to start with a fun fact connecting pollinators and Pride!  🌈

Did you know there are pollinators named after drag queens? A new genus of soldier flies were discovered in Australia 2020 and given names that are indicative of their metallic and rainbow-colored bodies! Among Opaluma fabulosa, O. iridescens, O. opulens, O. sapphira and O. unicornis are O. rupaul, named after the drag queen RuPaul, and O. ednae, named after the Australian drag queen Dame Edna. 

Soldier flies belong to the Stratiomyidae family, which include many flower-visiting flies! Many adult soldier flies visit flowers for nectar and subsequently transfer pollen on their bodies as they travel from one bloom to the next. Six of these seven Opaluma species were impacted by the Australian bushfires in 2019 and 2020; their recent taxonomic identification will allow them to be monitored in recovery efforts following the fires. The full citation for these stunning soldier flies can be found here.


To stay on the theme of iridescence, next we will share some information about my (Jen’s) favorite pollinators: Orchid bees! Orchid bees are in the same family as bumblebees and honey bees (Apidae) but are found within their own tribe, Euglossini. Within Euglossini, there are only five genera: Algae, Euglossa, Eulaema, Eufriesa, and Exaraete. Only one species of orchid bee is found in the United States (Euglossa dilemma), with the majority being found in Central and South America.

Not all orchid bees are iridescent– bees from the genus Eulaema are the exception, which are more similar in appearance to bumblebees than they are to the metallic members of Euglossini. I find orchid bees to be mesmerizing, not only because of their novel color forms, but also their unique adaptations. Some orchid bees’ tongues (proboscises) are more than 1.5 times their body length in order to access nectar located in long, tubular flowers! These bees often fly with their proboscis tucked under their body, and it may look like a small tail as it trails past their abdomen.

Photo © sixlegs on iNaturalist,
all rights reserved.

Euglossa have highly modified tibias on their hind legs. Male members of Euglossa species have a “pouch” on their tibia, used to collect and store floral fragrances from flowers in the form of essential oils. These oils are later used to attract potential mates. I like to think Euglossine males would be excellent candle makers.


Mallory’s favorite pollinators are long-horned bees, in particular those from the genus Melissodes, which are highly abundant in the latter half of our field season! Mallory loves long-horned bees because they have many traits that make them easily identifiable in the field. Males have elongated antennal segments which are indicative of their common name ‘long-horned’. They often have interesting colored eyes as well- some of the specimens we collect have green, blue or grayish eyes that contrast greatly with their often blond-colored hair (scopa). Her favorite trait, however, is the scopa on their hind legs. When full of pollen, long-horned females often look like they have ‘pollen pants’ on, in contrast to the neat and tidy pollen baskets seen on bumblebees! Svea thinks their pollen pants make long-horned bees look like they’re wearing a pair of western-style chaps. Melissodes primarily pollinate species from the Asteraceae, with specialization occurring on asters, daisies, and sunflowers. Sometimes Melissodes are called ‘sunflower bees’.

Melissodes sp. visiting a cosmo, photo by Mallory Mead.

Photo © armadillocommander on iNaturalist, some rights reserved (CC BY-NC).

Svea’s favorite pollinator is Anna’s hummingbird (Calpyte anna). C. anna is one of seven hummingbird species native to Oregon. Svea enjoys watching Anna’s hummingbird as a pastime at her parents’ house: they have a small, active community of hummingbirds that are very vocal and can be seen fighting over their nectar sources (including their butterfly bush and hummingbird feeder).

Svea also mentioned that the males are particularly pretty, though it requires a particular angle of light to make their iridescent copper-red colored throats glow. The ‘Anna’ in Anna’s hummingbird comes from the French Duchess of Rivoli, Anna Masséna, who was part of the court of France’s last empress (Eugénie de Montijo, 1853-1870). Anna’s hummingbirds are important pollinators in California, where they feed from coastal chaparral flora that share a similar phenology (breeding and feeding patterns) with the pollinator.


Nicole is another member of the lab whose favorite pollinator is a hummingbird! Nicole’s favorite pollinator is the Rufous hummingbird Selasphorus rufus. The USDA Forest Service describes the Rufous hummingbird as “small but feisty long-distance migrant[s]”. They are small in size and feisty in their protection of their feeding territories, they have been known to chase off other hummingbirds, large insects, and even people! Some of their preferred host plants include morning glory (Ipomoea arborescens), ocotillo (Foquieria spp.), shrimp plant (Justicia spp.) and red-colored blooms from the mint family, such as Salvia elegans and Stachys coccinea. Nicole loves the Rufous hummingbird because she regularly saw them while she was growing up. They could regularly be seen foraging and defending their territory in her parent’s yard.

Photo © Wendy Feltham (wendy5 on iNaturalist), all rights reserved.

Cara’s favorite pollinator is the Western Tiger Swallowtail Papilio rutulus. This magnificent butterfly can be commonly found at Cara’s research plantings of butterfly bush (Buddleja spp.), and can also be spotted basking on yarrow or slowly fluttering along the hedgerows at Oak Creek Center for Urban Horticulture. Despite the name ‘butterfly bush’, Cara has found butterflies to be infrequent visitors of Buddleja, though of the few butterfly visitors they receive, the Western Tiger Swallowtail is the most common. Cara additionally grew up seeing swallowtails every summer, which is why they are her favorite pollinator! To read more about this swallowtail, check out Lucas’s Pollinator of the Week Post.

Photo by Cara Still

Let us know who your favorite pollinators are!

A Bee’s Eye View: UV photography and bee vision

Flowers and bees have one of the most well-known symbiotic relationships ever formed. Flowers rely on bees for pollination, and bees rely on flowers for nectar and pollen. It is generally understood that flowers act as advertisements to attract bees. However, less is known about what exactly bees are seeing and how that can change once humans get involved. This project is focused on the changes that can arise after a plant is cultivated, and how these changes can affect pollinator preference of a flower.

While changes made by breeders might not seem all that drastic to our eyes, we have little idea if that is the case for bees. Often breeders will change flowers for aesthetic purposes. This can have unknown consequences. These changes might not seem like such a big issue since the flowers are still colorful. However, bee vision is very different from humans, with bees having the ability to see into the UV spectrum. This means that while we might think we are only changing the bloom size or the color, we could also be unintentionally changing UV messaging visible only to the bees.

The purpose of this study is to use UV photography to explore these invisible differences between the native and cultivar. We also want to determine if the differences have a tangible impact on pollinator preference. This study is ongoing, but the images so far have shown a few native/cultivar sets that have a marked difference in UV markers between native and cultivars. While the study has only just started, our excitement and curiosity have not abated. This is an entirely new foray into pollinator relationships and mechanisms and could open up the world of bees and flowers in a brand new way.

An example of a UV photo of a nemophila flower, with a UV marking in the center, highlighted in blue

How do we know what flowers bees like?

Pollinator Syndromes

Pollinator syndromes are the characteristics or traits of a flower that appeal to a particular pollinator. These traits often help pollinators locate flowers and the resources (e.g. pollen or nectar) that the flowers have to offer.

Syndromes include bloom color, the presence of nectar guides, scents, nectar, pollen, and flower shapes. We can use these traits to predict what pollinators might be attracted to certain flowers or we can use these tools to guide us to pick the right plant for the right pollinator!

Bees, for example, are most attracted to flowers that have white, yellow, blue, or ultra-violet blooms.

Blue Flax (Linum lewissii)
Male long-horned bee on a white bindweed flower
Orange bumblebee (Bombus sp.) on a sunflower

Pollinator Syndromes for Bees & Butterflies

Table adapted from the North American Pollinator Protection Campaign

TraitBeesButterflies
ColorWhite, yellow, blue, UVRed, purple
Nectar GuidesPresentPresent
OdorFresh, mild, pleasantFaint but fresh
NectarUsually presentAmple, deeply hidden
PollenLimited; often sticky or scentedLimited
Flower ShapeShallow; with landing platform, tubularNarrow tube with long spur; wide landing pad

What are nectar guides?

Nectar guides are visual cues, such as patterns or darker colors in the center of a flower, that lead pollinators to nectar or pollen. These cues are beneficial to plants and their pollinators because they can reduce flower handling time, which allows bees to visit more flowers and transfer more pollen in a shorter amount of time.

Northern Blue Flag Iris (Iris versicolor).

The petals (yellow arrow) and sepals (red arrow) both have dark purple nectar guides. The yellow portion of the sepals may also be a nectar guide!

Image courtesy of Mike LeValley and the Isabella Conservation District Environmental Education Program

While the iris’s nectar guides are visible to humans and their pollinators, this is not always the case. Some flowers have nectar guides only visible in ultra-violet light. The video below shows how different flowers look to us (visible light), and simulates what the flowers look like to butterflies (red, green blue, and UV) and to bees (green, blue, UV).

What about pinks and purples?

Red-flowering currant (Ribes sanguineum)

It’s not uncommon to see bees visiting flowers that are colors outside of their typical pollinator syndromes. In the spring in Oregon, we see bees visiting red-flowering currants, many pink and magenta rhododendrons, plum blossoms, and cherry blossoms. Lavender, catnip, and other mint-family plants too are common on pollinator planting lists, but tend to have purple flowers.

Pollinator syndromes can help us understand these anomalies. These flowers may appear differently in ultraviolet light or may have strong nectar guides that encourage bees to visit them, despite how they look to us. Alternatively, these flowers might have rich reserves of pollen and nectar that draw bee visits.

How else do we know if a flower is a good choice for bees?

Many people have developed plant lists based on personal observations, so there are many pollinator plant lists available to choose plants from. Many nurseries include pollinator attraction information with their planting guidelines too. While these are often based on anecdotal evidence, many researchers (including Aaron and I) are working to provide empirical evidence for plant selections.

To find native plants to attract bees and other pollinators, I recommend starting your plant selections by checking out your local NRCS Plant Materials program.

Many extension programs may also have regionally-appropriate plant selections! Here is the link to Oregon State’s list of native pollinator plants for home gardens in Western Oregon.

When you’re ready to buy some plants, make sure to check out this blogpost by Aaron.

2019 Native Plant Field Season Update

I’m thrilled to announce that this summer I completed the third field season of my study. This is slightly bittersweet – while I’m excited that we are done with hot fieldwork, I will miss chasing bees around the farm and the view of Mt. Hood. I’m incredibly thankful for this third season of data, as it will help account for some of the temporal variation inherent in ecological studies. In fact, pollinator communities in particular tend to be highly variable both within and across field seasons. Having three seasons of data will hopefully allow us to identify more reliable patterns of pollinator visitation between my study plants.

Lots of lab work remains, as I’m tackling the insect samples that we collected with the bee vacuum. With the help of a dissecting scope, I’m attempting to identify the each specimen to at least the taxonomic level of family to get a sense of the broader insect communities associated with each flower species in my study. It will be several months before I can share this species-richness data, but in the meantime I have bee abundance data to share with you!

Aaron and Lucas in the native plant study site, in 2017. You can see the 1m by 1 m plot in the foreground by Aaron, a second one near Lucas, and a few more in the distance.

As a refresher, we performed timed pollinator observations at each plot. This consisted of observing each blooming plot for five minutes and counting all the insects that landed on open flowers. Bees were sorted to “morpho-type” (honey bee, bumblebee, green bee, and other native bee). Though this doesn’t give us species-level information on the floral visitors, it allows us to understand which plants attracted the most pollinators overall, and allows us to detect any patterns of visitation between honey bees, bumblebees, and solitary native bees. Below is a summary of some of the highlights.

2019 overall bee abundance by plant species:

  • Origanum vulgare, Lavendula intermedia, and Eschscolzia californica were top five bee plants in 2019, just as they were in 2018.
  • In 2019, Phacelia heterophylla and Solidago canadensis jump into the top five, while Nepeta cataria and Gilia capitata fall out of the top five. It should be noted that Nepeta was the sixth most attractive plant, with about the same visitation level as Solidago.
  • Again, similar to 2018, it appears that honey bee visitation was driving the high visitation rates of the popular exotic garden species (marked with a red asterisk), while native wildflowers were being visited more frequently by native bees.
  • I’ve included the 2017 and 2018 overall abundance graphs as well, for comparison. You can see that the overall abundance was higher in 2019 for the two most popular plants, at about ~25 bees per observation period!

2017 overall bee abundance by plant species:

2018 overall bee abundance by plant species:

Since honey bee visitation drove the high abundance of many of the top pollinator plants, I took honey bee visits out of the data set and made a new graph, to compare which plants were most attractive to native bees.

2019 native bee abundance by plant species:

As you can see above, honey bees are excluded from the analysis, the top five most popular plant species completely reshuffles.

I’ve included that 2017 and 2018 native bee abundance data below for comparison.

2017 native bee abundance by plant species:

2018 native bee abundance by plant species:

Please stay tuned for more updates on the bee species richness we collected in 2019, as well as data on the other insects (pests and natural enemies) that we collected!

Isabella Featured on Pollination Podcast

Isabella Messer has been a member of the Garden Ecology Lab for more than two years, where she primarily assists with the garden pollinators study, but will is also developing her own research project. Her independent research project will look at bee visitation to some of the plants we are studying in controlled research trials, when these same plants are in a mixed garden setting. Controlled research trials are important, because they let us document the attractiveness of plants to bees, in a setting where study plants are not competing with other plants for pollinators. Controlled research trials are also valuable, because they let  researchers have better control over environmental conditions, such as irrigation. Isabella is going to see whether and how bee visits on plants in a garden context is different than what Aaron is documenting in his controlled research trials. This will be one of the first, if not the first time, that we will have direct and contemporaneous measures of bee visits on focal plants in each situation: in a research field, and in a garden.

In addition to her work in the lab, Isabella is also a member of the ‘Research Retinue’: a group of Oregon State University undergraduates, who review and discuss papers on the PolliNation Podcast.

In this episode, the retinue discusses two papers that look at the impact of a common herbicide (glyphosate) on bees, via indirect impacts of glyphosate on the microbiome (bacterial community) that can be found in honey bee guts.

The paper that they discuss is linked, below: