The Bees of Early Spring
March 24, 2022 | Permalink
Mining Bee (Andrena) visiting Miami Mist (Phacelia purshii)
There is hardly anything more thrilling than when those first wildflowers spring to life in our fields and forests, shaking off the winter gloom and tired browns and grays that have dominated the landscape for the last few months. As much as we love these early spring blooms, there are many other creatures whose lives utterly depend on them!
Beneath the soil and tucked away in crevices and cavities have been waiting a plethora of native bees and other pollinators. They have been sensing the temperatures and other changes taking place outside of their safe winter dwellings, trying to time their emergence just right. They need to coincide their yearly advent with the floral resources they depend on.
A newly emerged male Mining Bee (Andrena) at Sherwood Forest State Natural Area, Franklin County
For no other creatures is this more true than those we call the specialist bees. These species only utilize pollen from a narrow range of plants, in some cases only within a single family or genus.
Over a dozen of our early spring wildflowers and trees have specialist bees that depend on them, especially the ephemerals:
- Spring Beauties (Claytonia spp.)
- Violets (Viola spp.)
- Trout Lilies (Erythronium spp.)
- Toothworts (Cardamine spp.)
- Geraniums (Geranium maculatum)
- Jacob’s Ladder (Polemonium reptans)
- Waterleaf (Hydrophyllum spp.)
- Phacelias (Phacelia spp.)
- Alums (Heuchera spp.)
- Eastern Redbud (Cercis canadensis)
- Willow (Salix)
Look closely! There is a Mining Bee (Andrena) on this Wild Geranium (Geranium maculatum), Cumberland Trail State Park
Many of these relationships are poorly understood due to a lack of research and observations, so it is very possible that even more of these interactions exist than we are currently aware of.
While it isn’t always possible to identify a bee at a glance or even from a photo, there are certainly exceptions. One which makes identification fairly easy is the Spring Beauty Mining bee (Andrena eriginiae). These are tiny bees – many times smaller than a honey bee and only a little larger than a sweat bee (about 7-9 millimeters in length).
It is easiest to identify a female as she gathers pollen from the blooms of spring beauties. If you see a tiny, fuzzy bee and her legs are packed with pink pollen, then you have a Spring Beauty Miner.
She only gathers pollen from spring beauties, and you may have already noticed that their anthers are bright pink. This distinctive color makes these ladies especially easy to identify. If she has puffy pink pants, then she is your gal!
That pink pollen cake will be placed into nearby cells excavated underground. In each cell will be laid a single egg before she seals it up and moves on. These are the next generation of Spring Beauty Miners which will emerge when Claytonia blooms again the following spring.
Interestingly, the latest studies have contradicted what we have always believed about some specialist bees and their preferred plants. One would assume that a specialist is the most efficient pollinator of that particular plant species, but in some cases, the bees have become so adept at gathering pollen that they are spreading very little of it to other flowers.
This illustrates a long-standing tension that exists between pollinators and their plants. Each species has a different goal: pollinators are gathering resources to fuel their lives and provide for their young; plants need pollen transported to ensure fertilization and continue their species. While the relationship between pollinators and flowers has always been depicted as one of love and caring, it is more realistically an uneasy arms race where each tries to take best advantage of the other.
The little Spring Beauty Miner is a tiny window into this ever-evolving relationship. Perhaps in time, the plant will come up with a method to help mitigate the release of its pollen so that the miners no longer deplete it without pollinating.
In the meantime, the spring beauties rely mostly on bumble bees and other small bees to get the job done.
Another specialist to be on the watch for is Andrena erythronii, the Trout Lily Mining Bee.
They are quite a bit larger than the Spring Beauty Miner, almost honey bee sized, and can be seen gathering pollen from the lily’s stamens.
Mining Bee (Andrena) on Yellow Trout Lily (Erythronium americanum), Edgar Evins State Park
One interesting feature of a lot of our early spring woodland wildflowers is that they offer exclusively pollen to visiting insects. Nectar takes a lot of energy to produce, and if you are an ephemeral you must complete your life cycle very quickly before the tree canopy closes in, blocking the sunlight. A few species that offer only pollen are some anemones, bloodroot (Sanguinaria canadensis), twinleaf (Jeffersonia diphylla), poppies (Stylophorum diphyllum) and hepatica.
Bloodroot (Sanguinaria canadensis) in bloom at Edgar Evins State Park
There are also generalist bees that depend on these early bloomers. Newly emerged queen bumble bees require plenty of fuel when they first emerge in early spring. She busily gathers nectar and pollen to feed herself and her first brood of worker bees. Once her workers emerge she will remain in the nest and devote herself to egg laying for the rest of the season.
A newly emerged Brown-Belted Bumble Bee
Another early spring generalist is the Carlin’s mining bee, which looks very much like a miniature bumble or carpenter bee.
A Carlin's Miner Bee (Andrena carlini)visiting Purple Cress (Cardamine douglassii), Edgar Evins State Park
Most sweat bees also fall into the generalist category, and can be seen visiting a wide range of flowers in early spring.
Metallic Green Sweat Bee gathering pollen from False Garlic (Nothoscordum bivalve), Edgar Evins State Park
Tennessee is home to about 350 species of native bees which depend on a wide range of flowering plants to meet their needs. Early spring is one of the leanest times for these pollinators, so consider adding some early spring bloomers to your yard to help them out.
In addition to some of the ephemerals mentioned in this post, native trees and shrubs like willows (Salix), Serviceberry (Amelanchier) wild plums (Prunus) and blueberries (Vaccinium) are also excellent early resources. Many of our native bees only occupy a habitat of a quarter mile or less – your yard could be their entire world! Consider providing a diversity of native flowering plants that can provide for them throughout the season. (Look for a native plant nursery near you or consider joining a local Wild Ones Chapter to learn more about what natives would perform best in your yard.)
Re-wilding your yard by leaving stems, leaf litter, bare patches of dirt and wood piles also helps provide them with nesting sites (70% of our native bees nest underground). And of course, please avoid using pesticides or plants treated with neonictinoids.
A good book to add to your library is Bees: An Identification and Native Plant Forage Guide by Heather Holm. This book highlights a diversity of native plants and their associated pollinators to help you get started.
The next time you walk in the woods to enjoy those early spring blooms, be sure to linger awhile and pay attention to the plethora of pollinators that are visiting. These ancient relationships are vital to our ecosystem and for sustaining the biodiversity we so cherish.
Mining Bee (Andrena) on Cutleaf Toothwort (Cardamine concatenata)
Special thanks to my husband, Ranger Mark Taylor for succeeding in photographing the tiny Spring Beauty Mining Bee!