Bumble bee nests are notoriously difficult to find, leading to many questions surrounding bumble bee nesting habitat and behaviour. These questions are incredibly important to answer to ensure the conservation of declining species and to expand our knowledge of this important group of species – and that is exactly what I set out to do as a part of my PhD research at York University! This research was made possible by a number of funding partners including Wildlife Preservation Canada.

Bumble bees will nest in a variety of habitats, and in many different places! They can be underground (i.e., in old rodent burrows), on the ground surface but hidden by cover (i.e., under tussock grasses, decks/porches), or above-ground (i.e., tree cavities, bird houses). The entrance to the nest is often very small and hard to locate (often less than 2 cm wide). Here, the entrance of three different bumble bee nests is circled in yellow. Can you see the entrance? Would you have known there was a nest there if I didn’t tell you? People usually only notice nests in their yards or around their homes when they notice a fairly constant stream of worker bees returning to the nest with pollen or nectar.

Because bumble bee nests are often so well hidden (or are underground) we don’t actually get to see what the nest itself looks like. The image below shows a Bombus impatiens (common-eastern bumble bee) colony that was kept in the lab. The largest bee (near the bottom middle) is the queen, and all of the other smaller bees are workers that – if it were a wild nest – would help collect pollen and nectar to feed the colony and the developing larva. Some of the workers would remain in the nest to help feed the larva and incubate the eggs laid by the queen.

So, to help us find bumble bee nests and answer critical questions related to bumble bee nesting habitat and behaviour, we teamed up with the Working Dogs for Conservation who trained three detection dogs to locate the scent of bumble bee nests (using the waxy cells – the orangish coloured material in the nest photo).

We discovered that using detection dogs to find bumble bee nests was more nuanced that we first thought. Although the dogs were trained to the scent of bumble bee nests, and could locate them successfully, it might be beneficial (but not necessary) for dogs to be exposed to known wild nests. We gave this a shot with a team of dedicated volunteers and researchers but sadly the human team was unsuccessful in locating any wild nests before the dog team arrived!

We also learned that confirming nest detections can be tricky! This is because of a couple of factors including the possibility that the bumble bee nest could have multiple entrances.

It’s also important to keep the strengths and limitations of dogs in mind when designing a study that will use dogs to locate bumble bee nests. This includes carefully selecting study sites that are suitable for dogs and handlers to search, and research questions that are appropriate for this method.

To find out more details about this incredible project check out our research paper that is openly available on PloS ONE here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0249248

Amanda Liczner

Postdoctoral research fellow, University of Guelph and University of British Columbia Okanagan

Dr. Amanda Liczner is a postdoctoral research fellow at the University of Guelph and the University of British Columbia Okanagan. The research featured in this post was a part of her PhD in biology at York University under the supervision of Dr. Sheila Colla. Amanda’s PhD focused on identifying the habitat and management needs of North American bumble bee species. Her current postdoc position at the University of Guelph will be investigating the impacts of environmental stressors on bumble bee movement. Amanda is also working to complete a postdoctoral position at the BRAES institute at the University of British Columbia Okanagan on connectivity conservation challenges.