Miner bees, also known as chimney bees, are small, furry, and often mistaken for bumblebees due to their black and yellow appearance. These friendly and non-aggressive insects play a crucial role in pollination and are essential for maintaining a healthy ecosystem. They don’t typically sting or bite, making them ideal neighbors for any gardener. US Forest Service
These bees vary greatly in size, with some species resembling honey bees, while others appear darker and more metallic. Their nesting habits set them apart, as they prefer to build their homes in exposed soil, thin grass, and areas with good drainage. This ability to nest in a variety of environments makes them adaptable and widespread pollinators. University of Maryland Extension
Not only do miner bees play a significant role in pollinating plants, but they are also quite specialized, with life cycles that are timed to match the blooming periods of specific flowers. Gardeners and conservationists can encourage the growth of miner bee populations by providing optimal nesting conditions, such as dried mud blocks, thus helping to preserve these essential members of our ecological community. NC State Extension Publications
Miner Bees: An Overview
What Are Miner Bees
Miner bees, also known as mining bees, are a group of solitary bees. They are known for their ground-nesting habits and their importance as pollinators.
Miner bees prefer:
- Bare, hard soil
- Steep slopes
- Exposed soil
- Thin grass
- Good drainage
These bees emerge in May and remain active for around eight weeks. Gardeners can support miner bee populations by providing dried mud blocks for nesting.
Characteristics of miner bees include:
- Smaller than honey bees
- Stout and furry body
- Wide range of colors and patterns
- Some are brightly striped, others are metallic green
Miner bees are effective garden pollinators and play a crucial role, especially as honey bee populations decline.
Miner bees, part of the Andrenidae family, are solitary bees that nest in the ground, usually in sandy soil. They have velvety patches of hair called facial foveae between their eyes and the bases of their antennae.
The Life Cycle of Miner Bees
Mating and Reproduction
Miner bees are solitary bees with a fascinating life cycle. The mating process starts when males emerge from their burrows and wait for females. Upon encountering a female, they quickly mate, ensuring the continuation of their species.
Some key characteristics of miner bee mating:
- Solitary behavior
- Males emerge first, followed by females
- Quick mating process
Egg Laying and Larvae
After mating, the female miner bee prepares a burrow to lay her eggs. She provisions it with a mixture of pollen and nectar, which will serve as food for the developing larvae.
The egg-laying process:
- Female prepares a burrow
- She collects pollen and nectar as a food source
- Lays an egg in the burrow
- Seals the entrance
Once the eggs hatch, the larvae consume the stored food until they are ready to transform into pupae.
Pupa to Adult Bee
During the pupal stage, the miner bee larvae undergo a metamorphosis, eventually emerging as fully-grown adult bees. When the new generation of adults emerge, they continue the lifecycle by seeking mates and repeating the entire process.
|Stage of Life Cycle
|Laid in a burrow provisioned with food
|Consume stored food
|Metamorphose into adult bees
|Emerge from burrow, mate, and repeat the cycle
By understanding the miner bee’s life cycle, we can appreciate the important role they play in pollination and maintaining a healthy ecosystem.
Nesting and Foraging Behavior
Ground Nesting and Tunnels
Miner bees are considered ground nesting bees. They typically dig tunnels in lawns and soil to create their nests1. Here are some characteristics of their nesting behavior:
- Solitary insects
- Prefer areas with sparse vegetation
- Create individual burrows
These bees are gentle and rarely sting, so there is no need to worry about their presence in lawns and gardens.
Flowers and Pollination
Miner bees are excellent pollinators and forage-plant generalists2. This means they can pollinate a wide variety of flowers, including both wild and cultivated plants. They play a crucial role in the pollination process due to their ability to collect pollen effectively from multiple flower types.
Nectar and Pollen Collection
Miner bees collect nectar and pollen from flowers to feed themselves and their offspring3. They have high-energy needs, requiring both pollen (protein) and nectar (carbohydrates) to survive. Here’s a comparison table of pollen and nectar collection:
|Rich in protein
|Rich in carbohydrates
|Used for bee’s growth
|Provides energy for bees
Their foraging activities not only benefit themselves but also contribute to plant pollination and reproduction.
In summary, miner bees are ground-nesting insects with a gentle nature, and they are highly efficient pollinators. Their presence contributes positively to the environment and can benefit both wildflowers and cultivated plants.
The Role of Miner Bees in Pollination
Benefits to the Environment
- Pollination: Miner bees are essential garden pollinators and help in pollinating various plant species.
- Ecosystem support: These pollinators promote the growth of fruits and vegetables and contribute to a healthy ecosystem.
North America and Beyond
Miner bees are found not only in North America (over 4,000 types of bees), but also in Europe.
- Contribute to the annual $18 billion revenue added by pollinators.
- Highly efficient in pollinating fruit-bearing plants.
- Important for flower pollination and food production.
Key Plant Species Pollinated by Miner Bees
Miner bees effectively pollinate these key plant species, making them crucial contributors to the agricultural industry and the environment.
Challenges and Threats to Miner Bees
Pesticides and Exposure
- Miner bees exposed to pesticides experience declining populations.
- Pesticides are more harmful to miner bees than honey bees.
- Neonicotinoids, a common pesticide, can accumulate in soil and affect miner bee larvae when they consume contaminated pollen.
Nesting Area Disruptions
- Miner bees nest in bare, hard soil, often on steep slopes.
- They can be affected by changes in the landscape and human activities.
- Providing dried mud blocks for nesting could enhance miner bee populations.
- Soil disturbance affects nesting patterns, creating challenges for their survival.
Declining Bee Populations
- Declining populations of honey bees and bumble bees intensify the importance of miner bees in garden pollination.
- Miner bees need effective pollinator management to ensure their survival.
Comparison Table: Miner Bees vs Honey Bees vs Bumble Bees
|Role in Pollination
|Impact of Pesticides
|Effective garden pollinators
|Pollinators in gardens/fields
Characteristics of Miner Bees:
- They are smaller and stout-bodied, often mistaken for bumble bees.
- They are solitary bees, with each female digging her own burrow.
- Mostly non-aggressive and rarely sting.
- Important pollinators in gardens as honey bee populations decline.
Dealing with Miner Bees in Your Garden
Miner bees can be bothersome in the garden. To minimize the nuisance, avoid planting large patches of flowers. Instead, go for a scattered garden layout.
Creating a Bee-Friendly Environment
Encourage miner bees in your garden by providing the right environment. Some tips include:
- Plant a variety of flowers to provide nectar and pollen.
- Plant flowers in clusters to make it easier for the bees to find them.
- Provide a nesting area by leaving some bare ground.
Natural Control Methods
Control miner bees without using pesticides by using natural methods:
- Introduce natural predators like birds, toads, and spiders.
- Keep the lawn well-maintained, as taller grass blades may discourage nesting.
- Encourage hibernation by removing debris and mulch in the fall.
|Less attractive to miner bees
|May not deter determined bees
|Encourages healthy bee populations
|Could attract other bee species
|Reduces miner bee population naturally
|May affect non-target species
Follow these guidelines to balance between accommodating miner bees and keeping their nuisance under control in your garden.
In summary, miner bees are small, important pollinators that play a crucial role in our ecosystem. These bees are often mistaken for bumblebees, honeybees, or wasps due to their similar appearance1.
However, some key differences set miner bees apart:
- They are usually smaller than honeybees2
- Their bodies are often furry and uniquely patterned2
- Miner bees are solitary ground-nesters4
Enhancing miner bee populations can be beneficial for gardeners since they are effective pollinators3. Here are some features to remember:
- They emerge in May and have an activity cycle of around eight weeks3
- They nest in bare, hard soil, often on slopes3
Considering the decline in honey bee populations, miner bees can provide an alternative service in ecosystems. They may also be less threatening in close proximity to humans, as they are friendly, non-aggressive, and typically do not sting or bite1.
To further illustrate the differences, here’s a comparison table of miner bees and honeybees:
|Furry and patterned
|Less furry and evenly striped
|Solitary, ground nests
|Social, hive nests
|Can be defensive when threatened
By understanding and appreciating the unique role of miner bees, we can better support their conservation and the valuable benefits they offer to our environments.
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – Mining Bee
What type of bee?
April 13, 2010
We have three apple trees right next to our home and was outside looking for honey bees. I saw a few but mainly saw this type of bee. I have looked through some pics but can’t really determine which one it is. Any information would be appreciated.
We believe these are Mining Bees in the genus Andrena, but we would defer to an expert in this matter. According to BugGuide: “They have facial foveae. This describes the pale bands of hair along the inside margins of the eyes. Actually, the facial foveae are the ‘grooves’ in the face from which those hairs emanate.” BugGuide also indicates: “Considering the large number of similar-looking species, identification to species level usually requires an expert. Andrena are more active than Apis at lower temperatures. For this and other reasons Andrena (and Osmia…) can be, on a per bee basis, superior pollinators in cold weather. Some species such as Andrena clarkella are exceptionally cold tolerant.“
Letter 2 – Mining Bees
Tiny Bee or Ant
Location: Valley of Fire visitor Center 36°25’47.38”N 114°30’51.01”W
February 26, 2011 10:05 pm
Took this photo of a critter in a globe mallow at the Valley of Fire state park in Nevada. The flower is about 1cm across.
Signature: Just Curious
Dear Just Curious,
We will try to identify what we believe to be Bees in your photograph. The pale coloration is highly unusual. We wonder if perhaps these pale creatures are in the Tribe Neolarrini as pictured on BugGuide.
Identification courtesy of Eric Eaton
Yes, those are bees in the genus Perdita (family Andrenidae). Exceptionally diverse genus, especially in the southwest.
Letter 3 – Chimney Bees in Elyria Canyon Park
Mining Bees in Elyria Canyon Park
Location: Elyria Canyon Park, Mount Washington, Los Angeles, California
May 18, 2014 11:00 AM
So, walking back from the Elyria Canyon Work Party this morning, I was tasked with taping off the Indian Milkweed above the ranger station, and upon getting ready to leave, I noticed small perfectly round holes, slighting smaller in diameter than a standard pencil, in the hard packed earth of the trail.
I thought if I was patient, I might get to see the tenants. After several minutes, I heard a buzzing and watched a small winged creature disappear into one of the holes. I eventually got images of a Mining Bee’s head, several images of a Mining Bee excavating with only the abdomen showing, and an image of a pollen ball that has been gathered by the bee.
According to BugGuide: “Female digs long branching tunnel in soil, prepares brood cell at the end of each branch, and stocks cells with pollen balls and nectar. 1 egg is laid on pollen ball in each cell, then cell is sealed. Larvae develop rapidly and pupate in cells. 1 generation a year.” BugGuide also states: “Many small, ground-nesting bees observed in areas of sandy soil are members of the family, Andrenidae. Characteristics of this family (of which there are approximately 3000 species) are: Small size, 20 mm, (or smaller) brown to black in color, and nesting in a burrow in areas of sparse vegetation, old meadows, dry road beds, sandy paths. Although the nests are built in close proximity of one another, the bees are solitary (each female capable of constructing a nest and reproducing). Many species are active in March and April when they collect pollen and nectar from early spring blooming flowers. The female bee digs a hole 2-3 inches deep excavating the soil and leaving a pile on the surface. She then digs a side tunnel that ends in a chamber (there are about 8 chambers per burrow). Each chamber is then filled with a small ball of pollen and nectar. An egg is laid on the top of each pollen ball and the female seals each brood chamber. The emerging larval bees feed on the pollen/nectar ball until they pupate.”
Now that I was made aware of the nests on the trail, I saw several other areas that evidenced the development of a Colony of Mining Bees. The Mining Bees are very quick and wary, and it was impossible to capture an image of the full body of an individual.
Comment from Clare Marter Kenyon
so good to know they are still around. the last place i saw them was on the pathway from the barn to the trail half way to elyria!
I explored looking for bush lupine – going along dirt glenalbyn and then from Westpoint hiking down and am sorry to say I could not find any plants.
I did see some coffee berry though
Update: The following comment just arrived on another posting, referring to this posting.
January 16, 2016
Also, in regards to the archived post, I think those are actually Diadasia (unaware of a common name), and not mining bees (genus Andrena). What a cool find, impressive since it’s so tiny!
Letter 4 – Mining Bees look like the Dusky Winged Andrena
Subject: Mystery Wasp?
Location: Nashville, Tennessee
May 26, 2014 12:55 pm
Hi, I have been a big fan of your site for many years! There is some type of ground-burrowing wasp with blue wings that makes a nest in my yard every year. I usually see activity (little piles of dirt) around May, and by June or so it always seems like the nest is abandoned, and I never see any more signs of life until the following year. The nest spot in the ground is a patch about 2′ x 2′ with multiple holes.
This year, the nest seems larger, and there has been lots of activity. The creatures are about 1″ long, have blue wings, black bodies, and fat legs – especially the “hind” legs.
So far, they do not seem to be aggressive, but I would love to find out more about them.
We believe these are Mining Bees in the genus Andrena, and the closest match we were able to locate on BugGuide, from nearby Virginia, is the Dusky Winged Andrena, Andrena obscuripennis.