Pollinator of the week: Bombus fervidus

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This entry is from Angelee Calder, and undergraduate Agricultural Science student at Oregon State University. It highlights a bumblebee that can be found in Oregon gardens, but that is currently listed as ‘Vulnerable’ to endangered species status, due to documented population declines (Hatfield et al. 2015).

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Dorsal view, Bombus fervidus. This bumblebee was collected from a Portland area garden in August 2018. Photo Credit: Angelee Calder and Isabella Messer

Anterior view, Bombus fervidus. This bumblebee was collected from a Portland area garden in August 2018. Photo Credit: Angelee Calder and Isabella Messer

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When we think of bees, we usually conjure up the image of a cute fuzzy black and yellow puff of an insect. Bombus fervidus, which is also known as the Golden Northern Bumble Bee, looks just like that cute bee stereotype. This bumble bee has a black face, yellow body, and single black band across its body near its wings (Discover Life 2019). Although Bombus fervidus can be found across most of the whole United States, studies have shown that their population numbers are declining (Colla and Packer 2008). This bee is attracted to clover, which is one reason to tolerate (or even embrace) clovers in residential lawns.

We spent 120 hours hand collecting bees from 24 Portland area gardens in 2017 and 2018. In addition, across these two years we set out water pan traps to collect bees for an additional 3,450 hours of passive collection. In all this time, we only collected two Bombus fervidus. Both were collected from the same yard in August 2018. This yard is our largest garden, and it sits adjacent to Forest Park. It could be that this species, known to be in decline, does best with larger patches of habitat, that are close to a natural area.

The Northern Golden Bumble Bee is in the running for cutest bee, so make sure to take a look while he is out foraging. The peak viewing times to catch a glimpse of these cuties May to October (BugGuide.Net 2019).

References

Colla and Packer. 2008. Evidence for decline in eastern North American bumblebees (Hymenoptera: Apidae), with a special focus on Bombus affinis Cresson. Biodiversity and Conservation 17: 1379. https://doi.org/10.1007/s10531-008-9340-5.

BugGuide.Net. 2019 “Species Bombus fervidus – Golden Northern Bumble Bee”, https://bugguide.net/node/view/23135. Accessed February 27, 2019.

Discover Life. 2019. “Bombus fervidus“, https://www.discoverlife.org/mp/20q. Accessed February 27, 2019.

Hatfield, R., Jepsen, S., Thorp, R., Richardson, L., Colla, S. & Foltz Jordan, S.2015. Bombus fervidus. The IUCN Red List of Threatened Species 2015: e.T21215132A21215225.http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T21215132A21215225.en. Accessed  February 27, 2019.

Isabella Featured on Pollination Podcast

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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:

 

Native plants and pollinators – 2018 field update

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It’s been a while since I’ve posted a field update about my native plant – pollinator study, so this post will be a recap of the entire 2018 field season! Sampling this year was successful, though it was a much shorter bloom season for almost all the flowers species, perhaps due to a combination of the heat, low rainfall, and lack of supplemental irrigation. I performed some summary statistics on the data, and there are some intriguing results from this year.

Below is a summary of some of the highlights:

Visitation Data

  • Only two (Gilia capitata and Nepeta cataria) flowers made it into the top-five most attractive in 2017 and 2018. The full results can be visualized in the two histograms below.
  • Three of the non-native garden species were found in the top five in 2018 (though I noted this visitation seemed strongly driven by honey bees).

2017 overall bee abundance by plant species:

2018 overall bee abundance by plant species:

Because of this, I removed honey bees from the dataset and recreated the graphs.

  • The 2017 visitation data is largely unchanged (though Nepeta cataria is less attractive, and Eschscholzia californica jumps into the top-five).
  • When only native bees are considered, the top-five most visited 2018 plants are almost completely different. Eschscholzia californica, Aster subspicatus, and Phacelia heterophylla are the three most attractive flowers.
  • It seems like the native wildflowers are being visited more frequently by native bees.

 

2017 native bee abundance by plant species:

2018 native bee abundance by plant species:

Sampling Data
I also take vacuum samples from each plot so that we can identify pollinators (and other insects) to species. I’m excited that my 2017 and 2018 bees have been identified by taxonomist Lincoln Best!

​Across those two years, we collected 36 bee species (from 540 samples, which doesn’t include all the honey bee individuals). You might ask – is  this many bees, or only a few? Simply put – we don’t know! Without knowing how many bee species are found at our site at NWREC, its hard to tell what this number means. However, I was excited to find that we collected two bumblebees that are on the IUCN Red List, Bombus fervidus and Bombus calignosus.

Below are a two pollinator interaction matrices to visualize these data, but I should note that these are very preliminary – they are not scaled by number of sampling events but are still a neat way to visualize interactions and richness data.  (Darker squares represent higher abundance; a white square means no bees were collected off that flower).

 

Bumblebee Richness and Abundance:

Other Native Bee Diversity and Abundance:

 

Its obvious from looking at these data that the answer to the question “which plants attract the most pollinators?” isn’t simple! Are we interested in certain suites of bee species – honey bees, or bumblebees? Are we interested in high overall abundance, or high species richness? Some species attract many individuals but few species, while other plants attract a higher species richness but fewer overall individual bees. Additionally, there are also seasonal changes in bee populations to consider, as well as seasonal changes in flower phenology and floral display.

Luckily we’re going to have a 2019 field season, which will help account for this temporal variation and allow us to acquire data for species that didn’t flower in one or both of the previous years.

Plant of the Week: Douglas Aster (Revisited)

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Image from: http://www.nwplants.com/

This entry is from Lucas Costner, an undergraduate horticulture major at Oregon State University.  It highlights one of the plants that Aaron Anderson is using in his research.

Original “Plant of the Week: Douglas Aster” post available here: http://blogs.oregonstate.edu/gardenecologylab/2017/11/07/plant-week-doulgas-aster/ 

 

Last November I took a look at a Pacific Northwest favorite, the Douglas aster (Symphyotrichum subspicatum (1)). What I didn’t know then was just how popular this species would be with the bees we had been sampling in the field. It turns out that while surveyed gardeners ranked Douglas aster 14 out of 27 in terms of attractiveness, based on the 2017 data it boasted the third highest number of bees (2). This means that it is the most attractive native perennial species for bees that we sampled, and the 2018 data shows this as well (3). Based on the gardeners’ ranking, however, which placed it in the bottom 50% of all the species we sampled, it also looks as though the Douglas aster is in need of some public relations help. 

It is my personal belief that it isn’t just the showiness of the blooms or the potential benefits to X, Y and Z that brings plants into our gardens, but rather the stories we tell about them. Familiarity after all is more than just recognition; it is also marked by appreciation and understanding. One of the stories we can tell through our work in the Garden Ecology Lab about Douglas aster is of its relationship with our native bees. As gardeners we are uniquely positioned to both benefit from and to be of service to these insects. 

Here are some of their “faces”: 

Long-horned Bees

Melissodes sp. 

The most common genus of bees collected from Douglas aster in the field, Melissodes are true summer and fall flyers, easily recognizable by their long antennae. These bees are solitary ground nesters, although they have been observed forming nesting aggregations in the soil (4). While we collected potentially five species of Melissodes in total, one species in particular, Melissodes microsticta, was especially common. Many Melissodes species are generalists, but can usually be found visiting members of the Asteraceae family (such as sunflowers and our Doulgas aster) because of their late season blooms.

 

Image from: https://odabeeguide.weebly.com/melissodes.html

Yellow-faced Bumblebee

Bombus vosnesenskii

The second most commonly collected visitor of Douglas aster, the yellow-faced bumblebee is really a remarkable native pollinator. While many native bees are considered solitary, bumble bees are social insects, with a queen and workers (4). Like non-native honeybees, they have been investigated for their potential as commercial pollinators, being used in greenhouse production (5). Isabella Messer wrote a post for the “Pollinator of the Week” series highlighting these ubiquitous bees that can be found here: http://blogs.oregonstate.edu/gardenecologylab/2017/08/29/pollinator-week-yellow-faced-bumble-bee/ 

 

Image from: https://odabeeguide.weebly.com/bombus-sp.html

Ligated Furrow Bee

Halictus ligatus

The third most commonly collected visitor of Douglas aster is the ligated furrow bee. Found throughout North America, Halictus ligatus is special amongst native pollinators (like the yellow-faced bumblebee) for its social nature (4). Sociality is rare amongst native bees, as it is in nature in general, but amongst the Halictus the situation is even more unique. This is because, unlike other social species, Halictus have been seen to switch back and forth between solitary and social behaviors over time as environmental conditions differ (4). Isabella wrote a post about these bees a while back for the “Pollinator of the Week” series that can be read here: http://blogs.oregonstate.edu/gardenecologylab/2018/04/30/pollinator-week-mining-bee/ 

 

Image from: https://odabeeguide.weebly.com/halictus.html

Virescent Green Metallic Bee

Agapostemon virescens

The fourth most commonly collected visitor of the Douglas aster is none other than my personal favorite, the virescent green metallic bee. These stunning bees are communal soil nesters and are members of the Halictidae family, cousins of the ligated furrow bee introduced above (4). I wrote a post about them for the “Pollinator of the Week” series last November that can be found here: http://blogs.oregonstate.edu/gardenecologylab/2017/11/13/pollinator-week-virescent-green-metallic-bee/ 

 

Image from: https://odabeeguide.weebly.com/agapostemon.html

In addition to these bees, we also collected striped-sweat bees (Agapostemon texanus/angelicus), brown-winged furrow bees (Halictus farinosus), metallic sweat bees (Lasioglossum sp.), and common little leaf-cutter bees (Megachile brevis). We also collected with a number of long-horned bees (Melissodes) that have yet to be identified to species. 

Walking the streets of Portland and seeing Douglas aster’s purple flowers still in bloom this late in October brings a smile to my face because it tells me that people are indeed planting this species. If only for its benefit to wildlife and pollinators in particular, that is still good news. As you may be able to tell from the information given above, we are still learning about these bee species while we are simultaneously working to save them — not just for future generations but for ourselves as well. Hopefully, by putting a “face” to the bees that visit and depend on these plants and our gardens, the bond that links us to them can be strengthened and our preference for them in our landscape enhanced. 

 

Sources: 

  1. Geraldine A. Allen 2012, Symphyotrichum subspicatum, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=88843, accessed on October 30, 2018.
  2. Langellotto, G. (2018, September 12). Do Gardeners Like the Same Flowers as Bees? [Blog post]. Retrieved from http://blogs.oregonstate.edu/gardenecologylab/2018/09/12/do-gardeners-like-the-same-flowers-as-bees/ 
  3. Anderson, A. (n.d.). First Look: Research Into Native Plants in the PNW Garden. Webinar. Retrieved from http://blogs.oregonstate.edu/gardenecologylab/2018/10/23/webinar-on-willamette-valley-native-plants-and-pollinators/ 
  4. Wilson, J. S., & Messinger Carril, O. (2016). The Bees In Your Backyard. Princeton, NJ: Princeton University Press.
  5. Dogterom, M. H., Matteoni, J. A., & Plowright, R. C. (1998). Pollination of Greenhouse Tomatoes by the North American Bombus vosnesenskii. Journal of Economic Entomology, 91(1), 71-75. doi:https://doi.org/10.1093/jee/91.1.71
  6. Oregon Department of Agriculture: Bee Pollinators of Oregon. (2016). Retrieved October 30, 2018, from https://odabeeguide.weebly.com 

Webinar on Willamette Valley Native Plants and Pollinators

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Aaron’s webinar on his Ph.D. research has been posted on YouTube.

He highlights some really interesting results from his 2017 and 2018 field seasons, including recommendations for what to plant, if you are interested in attracting native bees to your garden. I’ve asked him to write a blog post, summarizing the results to readers.

Garden Bee Webinar

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In case you missed the webinar on our garden bee research, I’ve embedded the video, below. The entire webinar is about an hour.

And, make sure to mark your calendars for Monday, October 22nd at 11am PST. Aaron Anderson will be presenting a FIRST LOOK webinar on his research on native plant-pollinator associations. Visit the hypertexted link, above, to register for this FREE webinar.

Aaron was sharing some of his latest data with me, just this past week. His data, collected at replicated field plots in Aurora, Oregon, echoes what we’ve seen in home garden sites around Oregon: for native bees, Douglas Aster was a top performer.

Pollinator Survey

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Lauren Bennett, a Master’s student at OSU, is doing her capstone project on pollinators She has a short survey (10-15 minutes) on pollinators and pollinator plants.

If you could spare a few moments of your time, we would appreciate your participation in this study. More information this study can be accessed, by following the link, below.

http://oregonstate.qualtrics.com/jfe/form/SV_bw2OqokCObh83rv

FYI ~ this study was deemed ‘quality improvement / assessment’ and not ‘scholarly and journalistic’ by the OSU IRB. Thus, we do not need or have IRB oversight for this study.

 

Plant of the Week: Sunflower

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This entry is from Lucas Costner, an undergraduate horticulture major at Oregon State University.  It highlights one of the plants that Aaron Anderson is using in his research.

As summer in the Pacific Northwest comes to a close, the sunflower (Helianthus annuus) stands out as a classic garden favorite deserving consideration. These commonly large, tall yellow flowers are a boon to wildlife, provide late summer height and interest in the garden, and have shared an interesting relationship with people wherever we have encountered them. 

While there are many individual species and varieties available on the market today, wild populations can be found across North America, and most boast popularity with insect pollinators and other wildlife, including birds (1, 3). In the field, Aaron is using the wild-type and, while you certainly don’t have to do the same, varieties marked as “pollenless” or double-petaled should be avoided when planting for wildlife (3). Sunflowers seeds are well-known for their attractiveness to birds, but the flowers also provide forage to a diverse suite of insects, including bees, wasps, butterflies, and even beetles (2, 3). Four genera of native bee species (Diadasia, Eucera, Melissodes, and Svastra) host members that are sunflower specialists, and the giant leafcutter bee (Megachile pugnata) has even been studied as a managed pollinator for agricultural production of the crop (3). 

The giant leafcutter bee (Megachile pugnata).  Photo Credit: Thomas Shahan. Oregon Department of Agriculture.

Originally domesticated in eastern North America, the sunflower is the only native seed oil plant (1). Its use among North America’s indigenous peoples is well-documented and varied, having been used for everything from food to dye to medicine (2). The sunflower was introduced to Europe in the 16th century, where it first found its place in gardens, but it wasn’t until the 1800s in Russia that our modern ideas of giant, towering sunflowers came to be (1). This is because early American colonists did not cultivate sunflowers, and the seeds were reintroduced from Russia to the United States in 1893 (2). The Russians bred sunflowers that could produce up to 1000 seeds each for oil production, since the Russian Orthodox Church had forbidden the use of other cooking oils during the Lenten season (1). Therefore, in comparison with many common varieties available, and despite 3,000 years of domestication by indigenous peoples in North America, the wild-type appears quite diminutive (2). 

No matter the variety, gardeners should be aware that sunflowers are annual flowers that will need replanting every spring (although allowing squirrels to do the planting could be a fun experiment). They prefer well-draining soil and can reach rather impressive heights depending on the exact species and type. Additionally, the stems can become woody and may require some work removing at the end of the season. 

Sources cited: 

  1. Simpson, B. B., & Connor, M. (2014). Plants in Our World: Economic Botany (4th ed.). New York, NY: McGraw-Hill Education.
  2. Stevens, M. (2006, June 7). Plant Guide: Annual Sunflower [PDF]. Davis: USDA NRCS National Plant Data Center.
  3. The Xerxes Society. (2011). Attracting Native Pollinators. North Adams, MA: Storey Publishing.

Do Gardeners Like the Same Flowers as Bees?

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In 2017 and 2018, Aaron and Lucas took weekly counts of bees on their native plant plots. Aaron has summarized the data for 2017 (below) according to bee morpho-type. The morphotype categories are the same general categories that have been used by other researchers: bumblebee, honey bee, green bee, small bee, and big bee. These major bee categories are fairly easy to distinguish from one another in the field. Although, Aaron and I talked quite a bit about whether or not we should combine big bees and small bees into a new category: other bees. When does a small bee become a big bee? We had a general sense that a large Megachile rotundata would be a big bee, and a small Ceratina sp. would be a small bee. But, what about a smaller Megachile species? Is that big bee or a small bee? There is no clear answer.

Aaron and Lucas kept records of big bees vs small bees, as best as they could, but in the end, we might collapse all of that data into an ‘other bee’ category.Aaron recently surveyed gardeners, to ask their opinion on the aesthetics of his study plants. A quick look at the results suggests that gardeners and bees might be attracted to different flowering plants. While Gilia capitata was the most visited plant in Aaron’s study plots, it was ranked 6th most attractive (out of 27 plants) by gardeners. The story gets worse for Madia elegans (2nd with bees, 20th with gardeners), Aster subspicatus (3rd with bees, 14th with gardeners), and Solidago candensis (4th with bees, 23rd with gardeners).

Could it be that bees and gardeners are truly attracted to different types of flowering plants? Or could it be that if gardeners knew about the benefits of these Willamette Valley natives, that they might see a new kind of beauty in these plants?

 

First Bee List from Native Plant Study

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We are so lucky that Lincoln Best has been in Oregon, supporting the work of the Oregon Bee Atlas. Linc was kind enough to take a look at Aaron’s bees, before going back to Canada. Aaron is currently taking a bit of time off, following his wedding this past weekend (Congratulations Aaron and Maura!). In everyone’s absence, I’m chomping at the bit to see what bees were identified from Aaron’s study of Willamette Valley native plants. So ~ for your reading pleasure, here is a preliminary list of bees collected from Aaron’s plant plots.

Aaron and Lucas in the native plant study site. 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.

A few things to note about this list:

  1. I give no mention of abundance of each bee species. Some specimens were caught many, many times off of a flowering plant species. Others were rare, and only caught once.
  2. This list is not all-inclusive. It’s Labor Day. I’m working. I got excited about the bees, and wanted to share. But, I am not carefully going through every small label.
  3. Some bees were only found on one or two flowering plant species ~ even though Aaron’s plots are all in the same 3 acre field (1X1m plots, with each plot separated from every other plot by 6 m).
  4. Yellow-faced bumblebees were collected off of most plants ~ so I am not listing them, below. I also did not look at the honey-bee plant associations.
  5. Linc dissected male genitalia (yes ~ that is how you need to ID some bees to species), and found FOUR Bombus calignosus (all associated with lavender)~ a vulnerable species on the IUCN Red List.
  6. We also have Bombus fervidus, another species on the IUCN Red List (Vulnerable) on lavender, Salvia, and Gilia.

I’ll leave it to Aaron to make a rigorous accounting of bee-flower associations. But for now . . . on this holiday weekend, I was too excited to not take a peek and share initial findings with all o fyou.

Nepeta (non-native comparitor)

Oregano (non-native comparitor)

Salvia (non-native comparitor)

Lavender (non-native comparitor)

Phacelia (native)

Clarkia (native)

Goldenrod (native)

California Poppy (native)

Doug Aster (native)

Oregon Iris (native)

Gilia capitata (native)

Oregon Sunshine

Madia (native)

Sidalcia (native)

Yarrow (native)

Pearly Everlasting (native)