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The Quarterly Buzz

Updated: Apr 7

Newsletter of the Native Bee Society of British Columbia April 2023

Volume 4 | Issue 1


Editors-in-chief: C. Thuring & M. Marriott

Contributors: Sarah Johnson, Lincoln Best, Christine Thuring, Lori Weidenhammer, Marika Ai-Li, Elaine Sedgman, Helena Gadzik, Jade Lee, Paula Cruise

Spring Issue cover image: Andrena sp. on Bog Laurel (Kalmia) Photo: Sarah Johnson

Fly Straight to Article:


Research Corner

Founding director and former NBSBC president Sarah Johnson has published their first scientific article out of their PhD research at Simon Fraser University. Their research has taken them deep into the Chilcotin backcountry and on wild adventures into Tweedsmuir South Provincial Park and the Rainbow Range. These are amazing and wild places that very few people visit. After spending a few seasons surveying bumble bee communities in these remote mountain ecosystems, Sarah and colleagues have examined the influence of landscape variables, including the abundance and diversity of flowering plants, and forest fires, on these bumble bee communities.

--Lincoln Best

We are including here some additional images Sarah shared with us of the terrain and field work; below the photos you will find the abstract and link to the full article.

[Click on arrow to advance to the next image.]

Photo 1: Burn zone showing some of the encroaching unburned patch and diverse burn intensities. Photo: Harvey Thommasen

Photo 2: Field crew: Sarah Johnson with net, Jack Hall and Rowan Rampton looking for bees. Photo: Harvey Thommasen

Photo 3: Blue vane trap used for passive sampling (same large burn site as Photo 1, different vantage). Photo: Sarah Johnson

Positive impact of postfire environment on bumble bees not explained by habitat variables in a remote forested ecosystem

by Sarah Johnson, Hanna M. Jackson, Hutton Noth, Leithen K. M'Gonigle

First published: 24 January 2023:


Bumble bees are important pollinators in temperate forested regions where fire is a driving force for habitat change, and thus understanding how these insects respond to fire is critical. Previous work has shown bees are often positively affected by the postfire environment, with burned sites supporting greater bee abundance and diversity, and increased floral resources. The extent to which fire impacts variation in bumblebee site occupancy is not well-understood, especially in higher latitude regions with dense, primarily coniferous forests. Occupancy models are powerful tools for biodiversity analyses, as they separately estimate occupancy probability (likelihood that a species is present at a particular location) and detection probability (likelihood of observing a species when it is present). Using these models, we tested whether bumblebee site occupancy is higher in burned locations as a result of the increase in canopy openness, floral species richness, and floral abundance. We quantified the impact of fire, and associated habitat changes, on bumblebee species' occupancy in an area with high wildfire frequency in British Columbia, Canada. The burn status of a site was the only significant predictor for determining bumblebee occurrence (with burned sites having higher occupancy); floral resource availability and canopy openness only impacted detection probability (roughly, sample bias). These findings highlight the importance of controlling for the influence of habitat on species detection in pollinator studies and suggest that fire in this system changes the habitat for bumble bees in positive ways that extend beyond our measurements of differences in floral resources and canopy cover.

Read the full research article.


Sarah Johnson is the Founding President of the NBSBC, and a PhD student at Simon Fraser University studying bumble bee ecology and conservation in British Columbia. She has an MSc in Ecology from the University of Calgary and has worked in plant-pollinator research and native bee conservation across Canada for almost a decade, in academic, non-profit, and volunteer settings.


Native Bees Needs: Spring Edition

Supporting specialist bees: Introducing a new forage resource for BC

by Christine Thuring

BC has a nationally significant bee fauna. At nearly 600 species, BC harbours ⅔ of Canada’s known bee species. Most native bees are solitary and build their nests in the ground or in cavities. Each species has its own habitat, forage, and nesting preferences, therefore the best way to protect native bee populations is by protecting their habitat. Urban gardens can also help by reducing fragmentation, thereby supporting the evolution, adaptation and connectivity of native species.

The Native Bee Society of BC received funding from the Investment Agriculture Foundation of BC’s “Bee BC Program” to promote the planting of suitable forage for pollinators. We decided to focus on specialist bees that occur in two of BC’s most populated ecoregions, Coastal BC and the BC Interior. Specialist bees rely on specific plants to complete their life cycle, which makes them vulnerable to land use change. Generalist species, by contrast, are able to use many plants, and so will also benefit if specialists are cared for.

Thanks to the small team who worked hard (and had fun) crafting and curating the content (Bonnie Zand, Valerie Huff, Linc Best and Christine Thuring) of this colourful, double-sided forage resource. All are welcome to download, print and share them; find them at the respective link for ecoregion of interest: Pacific Maritime (Coastal BC) and Mountain Cordillera (Interior).

Why this forage resource?

Specialist bee populations are at risk when they are poorly understood. Lack of understanding of population distributions or specific floral relationships poses a risk to specialist bees because:

  • critical habitat may be lost;

  • forage plants may not be included in planting plans;

  • new/ invasive bee species may spread disease or compete for foraging and nesting sites.

Native bees and native plants evolved in mutual relationships with each other over the last 100 million years. While the peril of honeybee populations have captured public attention, native bees are in even greater danger because they are not explicitly cared for by human beings. “In the last decade pollinators, particularly bees, have come to the forefront of conservation importance due to their integral link to pollination, food supply and overall ecosystem health” (Sheffield and Heron, 2018, pp. 45). Loss of habitat is a threat to all species.

Wild bees need wild plants

Specialist bees rely on specific plants to supply the pollen needed to feed their offspring. Without their host plant, specialist bee populations can disappear. Landscapes that support specialist bees also benefit generalists (including honeybees), who have less restricted floral palates. The lists were developed with reference to Jarrod Fowler’s work on pollen specialist bees.


Christine is a founding member and current co-chair/ president of the Native Bee Society. She is a plant ecologist and Green Roof Professional, and a participant of the 2023 MeadowMakers Program. In 2023, she helped create forage resources for specialist bees in BC.


NBSBC Bee Tracker Update

The First Native BC Bees of Spring 2023

by Lori Weidenhammer

It’s so wonderful to see that bee foraging and nesting season is beginning in British Columbia!

The bumble bee queens are waking up in south coastal BC and Vancouver Island. I’m writing this on March 15th in Vancouver and I see it’s about to go up to 14 degrees Celsius in the next two days, so I’ll be looking for bumble bee queens to emerge from hibernation and start patrolling the ground, looking for a nesting sites. Please be sure to post your early bee sighting on the iNaturalist BC Bee Tracker project, no matter which part of the province you are in. We love to see those early emerging bees and please take note of which flowers you’re seeing them on if they appear to be gathering nectar and/or pollen. These early days of spring are so important to our spring bees and we need to know which plants are supporting them. You can add the plant association in “observation fields” on the right side of the observation page.

The earliest bee we’ve had recorded so far was a Bombus melanopygus queen on heather on Feb 17, in Saanich. Non-native heather that blooms at this time of the year does seem to be an important spring garden booster for our early bumble bees. I often see some of the earliest bumble bee sightings in the heather garden at VanDusen Gardens in Vancouver.

On March 8 our co-president Paula Cruise spotted a beautiful B. melanopygus queen on a windowsill on the Sunshine coast. Looks like she’s covered in some kind of golden pollen.

On March 9th there was an observation of B. melanopygus on purple crocus on the sunshine coast highway, Sechelt, BC. On the same day, one was spotted sunning herself on mulch in Langley. This makes sense as they often bury themselves in mulch an/or soil to hibernate over the winter.

Black-tailed Bumble Bee Photo credit: deciduousdaydream
Black-tailed Bumble Bee on Pieris japonica Photo from iNat bee tracker deciduousdaydream

On March 11, an observer got some beautiful photos of B. melanopygus on Pieris japonica. These cup-shaped flowers are often popular with the blue orchard mason bees as well.

On March 12 a beautiful female Andrena mining bee was observed at the University of Victoria. Looks like the observer is wearing gardening gloves, so I wonder if they gave her a little nudge and disturbed her underground overwintering spot when they were digging in the ground. Or maybe she was just in a nice warm spot and emerged early.

On March 14, a Bombus mixtus was observed sunning herself on the outside of a daffodil in Saanich. I always think it’s such a shame that so many acres are devoted to a flower that does nothing for bees, except offer them places to shelter and sleep. Sometimes they sleep inside the middle of the flower and other times, they perch on the outside. Same goes for the big tulips that are popular at this time of the year. I’d much rather see native spring flowers and shrubs such as red flowering currant, Oregon grape, pussywillow, and osoberry.

We are also starting to receive a few sightings of Bombus vosnesenskii emerging on Vancouver Island in March. These elegant black and yellow bumble bees are some of the most common we see on the southern BC coast.

I’m seeing the red flowering currant budding out here in Vancouver. Salmonberry, shortspur sea blush (Plectritus congesta) and camas will be coming soon!!! Oh, I’m so excited! I see there was a sighting of a Vancouver Island bumble bee on a satinflower (Olsynium douglasii) on April 2 in Victoria, from 2022, so that’s something to look forward to!

Friends, I would love you to join me Sunday, April 30 camas day in Uplands Park (watch this website for details). Hope to see you there!


Lori Weidenhammer is a performance-based interdisciplinary artist and educator. She is the author of a book called Victory Gardens for Bees: A DIY Guide to Saving the Bees published by Douglas and MacIntyre. Lori works with students of all ages on eating locally and gardening for pollinators. On occasion, she likes to dress up in silly costumes and talk to bees. She worked with Tyler Kelly and curator Lincoln Best to create and maintain the iNaturalist BC Bee Tracker Project. She is a recipient of the Entomological Society of Canada’s Norman Criddle award for her work as an amateur naturalist. This year Lori would like to focus on creating educational materials that can be used by the public in many situations to deepen their understanding of native bees and their habitat needs. She would like to find new ways to bring inclusive and accessible artistic creation into the process of connecting folks to BC native bees.


The BC Native Bee Course is back!

The Native Bee Society of BC is excited to offer two short courses this coming June, 2023. We have capacity for 30 individuals across two sessions with overlapping field days:

  • June 15 - June 18, 2023

  • June 17 - June 20, 2023

This course offers a deep dive into native bee identification, field methods and ecology. It takes place in BC’s Okanagan region, which hosts the highest diversity of native bees in Canada. For those new to searching for bees in this biodiversity hotspot, we guarantee you’ll encounter a great variety of species.

Labs take place at Okanagan College in Penticton (see map), with field days at Sawmill Lake in Oliver. The course syllabus is available here.

For details about application, course fees, instructors and more, visit

Applications are due by April 7, 2023. Apply Now!


Special Report: Houdini Flies in BC

Who they are, how they've spread, and what you can do

by Marika Ai-Li

Megachilidae, commonly referred to as hairy-belly bees and cavity-nesting bees, is the most diverse family of bees in BC. There are over 150 species in the province (Sheffield & Heron, 2018), including many of our most visually stunning native bee species who carry fascinating life history traits. Females can be seen flying with yellow, orange, white or even blue “bellies”, carrying pollen on dense scopa on the underside of their abdomens. Most species nest in found cavities including loose bark, insect holes, snail shells, pine cones, and human-constructed bee houses. Females of some species use enlarged mandibles to collect leaves, petals, mud, and plant hairs to partition, and sometimes “wallpaper” their nest cells (Wilson & Messenger-Carril, 2016). Cavity-nesting bees are vital pollinators in BC’s ecosystems. Some species, such as our native blue orchard mason bee (Osmia lignaria), are managed for commercial pollination services in orchards across North America and Europe.

The flies have arrived

Cavity-nesting bees are facing a new threat in the Pacific Northwest. The “Houdini fly” (Cacoxenus indagator), native to Europe, is a kleptoparasite of mason and leafcutter bees, whose larvae feed on pollen in the nests of Osmia cornuta, O. bicornis, O. uncinata, and Megachile rotundata in Europe, and more recently, O. lignaria in North America (Krunić et al., 2005; Müller et al., 2020; Strohm, 2011; Zajdel et al., 2016; Zadjel et al., 2014). The first specimen of C. indagator recorded in BC was submitted to the Spencer Entomological Collection in 2014 (K. Needham, personal communication March 22, 2023). Since then, C. indagator has spread and established along the west coast, with iNaturalist reports across coastal urban areas of southwestern BC, Washington and Oregon.

Photo of Cacoxenus indagator adult.
Cacoxenus indagator are in the fruit fly family (Drosophilidae). Adults are 3-3.5 mm long, with a light-grey thorax a black abdomen with horizontal banding and distinctive brown to dark-red eyes (2). Credit: Crown Bees.

Crown Bees in Woodinville, Washington rear and distribute nearly half a million O. lignaria cocoons annually. Owner Dave Hunter curiously observed a few cells infected by fly larvae amongst cocoons in 2018. In 2019, he 500 cells had been taken over, and in 2020, numbers grew close to 5% (25,000). This led Dave to confirm identification with experts in Switzerland and start to pro