People often ask me how to find ground-nesting bee nests. In reality I see nests in the ground all the time but most are very tiny and aggregations are fairly infrequently encountered. Here is a time-series of a Lasioglossum sp. female at the entrance of her nest, likely only 2-3 mm in diameter. She quickly saw off the more brightly colored male.
I observed a couple of two-spotted sunflower bees, Melissodes bimaculatus, foraging for pollen on this Floriani Red Flint corn in Boulder, CO. While it may seem strange, I observe bees foraging on corn and other grass for pollen fairly frequently. These could provide important resources if other host plants are scarce or may be used to supplement pollen provisions. These two bees returned repeatedly and filled their scopa up each time. You can easily see the yellow corn pollen packed onto their hind legs.
The western bumble bee, Bombus occidentalis, is an uncommon visitor in Boulder. This one was spotted foraging on black berry flowers in the Shakespeare Garden at CU-Boulder. This species is thought to be in decline in parts of its range so it's a welcomed sight just outside the Museum of Natural History!
This summer I'm working with Boulder County Parks and Open Space to document native bees along riparian areas impacted by the 2013 flood. One of our goals is to identify important floral resources for bees. Nearly three years post-flood, it's especially interesting to see how both the floral communities and the bees are returning to some of the most heavily impacted areas.
We're working with Alex Morphew, an undergraduate honors student at the University of Colorado to document patterns of native bee performance across agricultural regions of eastern Colorado. Above are some of the beautiful images we're capturing of the intricate cells constructed by female bees (and a wasp) that both highlight the complexity and beauty of these remarkable animals.
We have been very fortunate to have a very talented film maker help us document our research on the plains. Check out some of Travis' videos at the links below.
Spring has definitely arrived and with it some early season bees to our bee blocks. I caught up to this blue orchad bee, Osmia lignaria, as she brought in some late evening provisions to one of her cavities. You can see the mud she uses to cap off the nest in the hole above her.
Occasionally, we find some very strange looking bees. These two series of photos are both of long-horned bees in the genus Melissodes that I asked Brian Lobbes to image. However, something is distinctly odd about their faces. Male long-horned bees usually have yellow faces and long antennae (hence their common name); but both of these bees have half yellow faces and one long antenna. In fact they are both male and female, or gynandromorphs. Gynandromorphy typically arises from a problem with chromosome segregation during mitosis and can lead to the organism having some cells that become male and other cells that become female. In the top specimen, the bee appears to be mostly female, with hairy legs to collect pollen but the right side of the face and antenna are male. In the lower specimen, the body is more male, lacking those bushy leg hairs, and with alternating female patches on the face: a dark right mandible, dark left face, and short (female) right antenna. So cool!
As we identify all of our bees in the museum we're finding some really cool species. The native bee, Cemolobus ipomoeae, is a new species for Colorado and represents a big jump in the known distribution, as it was historically not found west of Missouri. It is also a specialist bee, feeding on morning-glories (Ipomea sp.). Hence it's specific epithet, ipomoeae. These images were taken by Brian Lobbes in the CU Entomology Collection.
We were extremely fortunate this year to have an undergraduate interested in photographing and filming some of our research, Travis Bildahl. I think his images speak for themselves.
If you've ever been driving down those back roads and seen some silly folks running around with nets, chances are they were entomologists. Netting is a very useful tool to look for bees that don't come to attractive traps. Given that bees are often small and super fast, you may see some netting high jinks alongside the roads so watch out!
Bees are pretty unique in that they are almost completely dependent on flowers to survive and reproduce, and a major part of the latter is due to pollen. Most bees provision pollen for their young and by sampling the pollen they carry we can gain a better understanding of the types of plants they use and the species most important to developing young. To help identify that pollen, we collect samples in the field and build a reference pollen collection to compare to samples back in the lab.
You may have noticed we use bright colored traps to entice bees in to visit. These are very effective at capturing bees for us while we collect other data on grass and flower species.
We're back for our final year of field work. Along with our bee and plant diversity surveys, this year we are also installing some custom bee nest boxes to see how many different cavity nesting solitary bees are on the plains. This is collaboration with the Museum of Natural History and The Bee's Needs Program. We placed similar bee houses along the Front Range and are curious to see what bees use them out on the high plains.
Spring is here and bees are starting to fly across the foothills and plains. For these early season bees, finding flowers can sometimes be a real challenge. Although they are exotic, dandelions still provide an early source of pollen for many bees including honey bees and native bees. They are also a good nectar source for the male mason bee above.
Here's a picture of the development of a leaf-cutter bee species we collected in our bamboo nests. After eating all of the provisioned pollen within its cell, the last instar larva (left) molts into a new pupa (2nd from left). The older pupa (2nd from right) looks much like an adult bee (right) but is still developing it's wings and other internal anatomy.
For those of you interested in native bees, there's a new collaborative citizen science project to document occurrences of those big and charismatic buzzers, the bumble bees. At Bumble Bee Watch you can upload photos of bumble bees, learn ID, and check out recorded sightings in your area! I'm sure I'll be adding some photos to their database soon!
Also, another citizen science project occurring locally is The Bees' Needs. Through it you can help participate in a study documenting wood nesting bee species all along the Front Range. Details on both studies can be found on their websites.
We used bamboo to collect stem nesting bees. This not only allows us to see which species are present, but also what types of plants are important for building and provisioning nests.
I am a Postdoctoral Associate at CU-Boulder and have lead a number of projects studying patterns of native bee diversity in Colorado. Please enjoy your visit and contact me if you have any questions.