What are Mining bees
Mining bees are a species of ground-nesting solitary bee.
In the UK there are 67 different species making them part of the largest bee genus in the UK. The other 3 main groups of solitary bee include mason bees, leafcutter bees and carpenter bees.
Mining bees are solitary bees
Miner bees do not live in colonies like Honey bees and bumblebees. They are what is described as sub-social, meaning they reside in loose groups, living in the same area, utilising the same sources for pollen & nectar.
Loose groups is a term that reflects that there will often be a concentration of nests within a small area, which can give the misleading impression of a bee colony.
Period of activity of Mining bees
Typically you may find activity in your lawn or flower bed between April & June. The activity period is usually short, only for a few weeks. Exactly when during this time period will depend upon the species active, the weather conditions, and where in the country you are located.
This period of activity may vary, for example the Ivy mining bee will be active going into Autumn taking advantage of the late flowering ivy.
Life cycle of a Mining bee
At the beginning of the bees active period the males will first emerge from the burrows, usually a couple of days ahead of the female. These males will actively search the area for the emergence of any females that they can mate with, mating several times before dying.
After mating, female bees will excavate a burrow creating up to 3 shafts, (these can extend down by as much as 60cm) each one with up to five nest chambers (a smaller burrow).
She will collect & store a pile of pollen in each nest chamber, then cover the pollen with some nectar, and then lay a single egg on the pollen pile before sealing the chamber.
The egg will hatch, the larvae will consume the nectar & pollen store, pupate and then emerge a year later for the process to be repeated again.
Mining bee volcano excavations
Mining bees excavate burrows and whilst doing so create mini volcano like heaps of soil around the bee entrance.
These mounds are usually about 5cm high with a hole approx. 4mm wide at the top of the mound.
Each of these mounds is a separate entity and are not interconnected.
These burrows do not cause damage to the lawn but helps with the aeration and drainage of the lawn, and the piles of soil soon disappear.
Can Mining bees sting?
Mining bees are fairly harmless.
The females can sting, but will only do so if defending the nest or if she is accidentally trapped or stood on.
Apparently their sting is rated as a 1.0 on the Schmidts Sting Pain index. Indicating that any discomfort is unlikely to last any longer than 5 minutes.
Personally it’s always been my understanding that their stinger is so short it cannot actually penetrate the skin, so there is unlikely to be any reaction, but I cannot say this as fact.
I am also unaware of anyone that has suffered any discomfort from a sting from a Mining bee (would love to hear from anyone that has, so that I can update this post to reflect otherwise)
What to Do if Mining Bees Inhabit Your Lawn
Generally speaking, Miner Bees should be left alone to live their lives.
Remember after just 5 or 6 weeks the bee activity will die of, you won’t see them again until the following year.
If you’re concerned about the site of the mounds of soil they create, this can be easily brushed back over the lawn in the same way you would brush away dry worm casts.
Don’t call a pest controller who is offering the option of extermination, bee & insect populations in general are in extreme decline, so in my opinion there’s no excuse for killing them. Anyway, there are no insecticides licensed to do this, either for the mining bee or the circumstances of the bee nests, so any pest controller offering an extermination service would be best described as a cowboy.
Do not use an ant or wasp powder, spreading it liberally across the lawn or beds – think of what else this is doing to the environment and how bad this is for your lawn. Read the label and see for yourself that this is not how it should be used.
Any treatment used should be some sort of natural treatment. To describe any such treatment as environmentally safe would clearly be inaccurate as these are a harmless beneficial insect generally in decline.
If they really cannot be lived with
Concentrate on creating a thick lawn using good lawn care practices throughout the year. Mining bees prefer areas with less grass cover as it makes it easier for them to access the nest. Keeping your lawn thick and lush will help keep them away.
Some suggest using cinnamon sprinkled over the lawn, or cinnamon sticks adjacent to the bee entrances, others suggest using essential oils found in the kitchen cupboard such as lavender, peppermint and tee tree oils as bee deterrents.
Personally I am not convinced, but I don’t know.
Doing this would at least allow the new bees to emerge and hopefully allow them to find a new location to nest: although they will need similar ground conditions (soil type, etc) and similar local flora. Even if only partially successful, this may ease the number of bees using the area to a more manageable number for those that are having real problems.
Lastly and least preferable option, would be to turn the soil over in that area, most seem to suggest doing this in autumn/winter time, I’m not sure why, after all the population is likely to be wiped out, would it not be better to do it just as they are about to emerge to give them the opportunity to find an alternate nesting site?
SwarmCatchers Miner Bee prevention: untested solution
Based on what we (SwarmCatcher) know about various bee species this may well be an appropriate method to reduce numbers year on year. Personally I would not want to do this but it may be the most practical method for those that have a real problem.
Our untried idea is to place 1.5mt squares of netting over the ground, this would allow the seasons new emerging bees to exit their tunnels and to find their way out from beneath the netting, but prevent the mining bees from being able to access the same ground to make new nests.
It would be great to hear from anyone trying this idea out, and what kind of success they had, with what kind of netting and the spacing used.
Scaffold debris netting would probably be a good option for this?
Benefits of Mining bees
In the garden, Mining bees are extremely beneficial insects.
They pollinate plants & crops – just like honey bees, they pass from flower to flower collecting pollen and nectar, and whilst doing so cross pollinate the flower heads. Often they are the specialist pollinator for specific plants, ie the Ivy Mining bee on ivy, or the Red Mason bee on an apple orchard (400 times more efficient than a honey bee).
They are “Your Lawn’s Natural Aerators”, just like earthworms, ground-nesting bees are nature’s natural lawn aerators, their burrow shafts reach down to a depth of 60cm, with a diameter of 5 to 7mm, so allowing good air movement into the ground.
The mining bees burrows do not (to my knowledge) cause any harm to plants, but can also assist in soil drainage.
Mining Bee identification
The biggest give away for most, is their nest, but once away from the nest they can be more difficult to identify.
Mining bees are quite variable in size depending on the species, ranging from 5-17mm long.
Mining bees are characterised by grooves running down the inside of their eyes (called facial fovea), in the UK there are no other bees that have this characteristic.
Just like honey bees and bumblebees, mining bees collect pollen on their hind legs.
More about specific species of Mining bees
Tawny mining bee – Andrena fulva
The Tawny Mining Bee is the most common. They fly from March to June.
The females of this species are the easiest to identify, with a thick rusty red coat and about the size of a honeybee.
The males are smaller and brownish.
The females create nests in short turf and lawns, and in areas of light soil or a bare bank.
They forage on early flowering shrubs and trees including willow, hawthorn, blackthorn, as well as fruit trees.
This species that is frequently targeted by the Large bee-fly (Bombylius majora), a parasitoid of Mining Bees and some solitary wasp species. This bumblebee mimic will often be seen hovering over an open nest cavity and flicks its eggs inside. Its offspring will then hatch in the nest and consume the pollen left by the adult Mining Bee, as well as the young bee larvae!
Ashy mining bee – Andrena cineraria
The Ashy mining bee typically flies from April to early August.
The females are very distinctive with monochrome colouring – black with two ashy grey bands on their back.
They can be found in a range of habitats including heathland, open woodland, coastal grassland, quarries, gardens, parks, orchards and around cropped agricultural land.
Their preferred food plants include blackthorn, willow and fruit trees, but they can be found foraging on a wide range of other flora.
Ashy Mining Bees are also known for nesting in lawns and create soil piles next to their tunnel entrances.
They usually close their nest entrances one they have finished their days foraging, when it rains and if they are disturbed. This also helps protect the nest from intruding parasites.
Early mining bee – Andrena haemorrhoa
The Early mining bee is a common spring bee species flying from March to July.
Their length varies from 8 to 11mm.
The females have a striking blood red tip to their abdomen and a covering of foxy brown hairs on their back.
The male is smaller and a lighter colour, often looking greyish.
Nesting sites include gardens, sports fields and road verges etc.
They like early flowering species such as willow, blackthorn, hawthorn, and a particular favourite are dandelions. It is also considered an important pollinator of fruit trees.
Hawthorn Mining Bee – Andrena chrysosceles
Although common across most of England they are more scarce in the South West and Wales and are much less common in gardens.
They generally fly April to June.
They have a body length of 7 – 11mm.
They are similar looking to the Early mining bee but generally darker. The females can look almost black with only a few buff coloured hairs on the thorax and head. Their abdomen is shiny, with white bands of short hairs between the segments and orange hairs on the tip of the abdomen.
Hawthorne mining bees like to visit blackthorn and hawthorn flowers often reaching peak numbers when hawthorn and cow parsley are in flower.
The females typically nest alone rather than communally and typically prefers woodland edges and hedgerows.
In summary
Personally if I had an area being utilised by ground-nesting bees I would be protecting it, and enjoy the privilege of being able to see these bees at work.
It may be advisable to wear shoes, just in case they can sting and cause discomfort (or worse) should you step on one. Though whether they can sting and cause discomfort is still not clear to me.
They are unlikely to sting you or your pets.
If you are stung its more probable that it is by some other bee or wasp.
In the meanwhile if you do have mining bees in your garden please submit sightings to iRecord: https://www.brc.ac.uk/irecord/ to help build a clear national picture of the state of our precious wildlife.
