of Rhode Island GreenShare Factsheets
Bees & Ground Nesting Wasps
Mining bees, or digger bees, (familys
Andrenidae & Anthophoridae)
nest in burrows in the ground. Unlike the honey bee, mining bees
are "solitary" bees. They do not form long-lived colonies, nor
do they live inside a single, well-defended nest controlled by
one queen bee. Instead, each mining bee female usually digs her
own individual burrow to rear her own young. Large numbers of
these bees may nest near one another if soil conditions are suitable.
Mining bees are not aggressive and seldom, if ever, sting.
The presence of numerous bees flying close to the ground, however,
may constitute a nuisance for some people. Sometimes large numbers
of males will fly about the same spot for several days in a mating
Mining bees range in size from about the size of honey bees
to much smaller. The larger bees are furry and usually darker
in color than honey bees. Some are brightly striped, while others
are a shiny metallic green. Mining bee burrows may be located
wherever there is exposed soil and good drainage. They are frequently
found nesting in banks, such as along road cuts or any type of
excavation, but may also be in level ground as well. The holes
are about 6 mm (1/4 inch) or less in diameter. They are sometimes
surrounded by a small mound of soil that the bee has brought
up to the surface. Burrow structure varies according to species,
but often there is a vertical tunnel with smaller side tunnels
that terminate in a single cell.
The female mining bee stocks each cell with pollen and nectar
she collects from flowers and then deposits an egg on the food
mass. The larva hatches and consumes the stored pollen and nectar.
When mature, it becomes a pupa, or resting stage, and finally
becomes an adult bee. The adult bees overwinter below ground
in the burrow site. During the next spring or early summer the
adults emerge, mate, and the females begin burrow excavation.
Mining bee populations can fluctuate dramatically from one season
to the next.
Many species of wasps are also solitary
and nest in the ground. They have a life cycle similar to that
of the mining
bees. After preparing a burrow, the female wasp stocks it with
provisions (which consist of insect or spider prey rather than
pollen and nectar), lays one or more eggs in it, seals it and
departs. Some species don't permanently seal the nest, but instead
return repeatedly with additional prey as their larvae grow.
These wasps range in size from extremely small forms to the large,
fearsome looking "cicada killers."
Cicada Killers (Specius speciousus): Cicada
killers resemble large yellowjackets. They are mostly black with
pale yellow markings on the abdomen, and about 5 cm (2 inches)
long. Despite their appearance, these insects are inoffensive
and usually will not bother people even when provoked. Their
sting is meant for paralyzing their prey and normally does not
cause a reaction in humans. They are considered beneficial because
they reduce cicada populations. However, they may cause lawn
damage if there are large numbers of them nesting in close proximity
to each other.
Another group of ground nesting wasps are the Scoliid (family:
Scoliidae) or Tiphiid (family: Tiphiidae) wasps.
Scoliid wasps are about 16 mm (5/8 inch) long and blue-black,
with blackish-purple wings. They have a yellow stripe on each
side of the abdomen. Their bodies are fairly hairy and the back
part of the abdomen is covered with reddish hairs. Tiphiid wasps
are black and somewhat hairy with short, spiny legs. Both wasps
are generally seen flying over the lawn during the day, leaving
in early evening. Scoliids and Tiphiids are beneficial wasps
in that they parasitize grub populations. They are not aggressive
and generally do not attack humans. Adults are often seen on
golden rod flowers in the late summer.
It must be stressed that mining bees are extremely beneficial
insects, of considerable importance in the pollination of many
different types of plants. Their burrowing does not harm vegetation
and may actually be of service in aerating the soil. Furthermore,
the activity of these species is extremely brief, with adult
bees flying for only two to four weeks. In some instances, the
bees observed are males flying about their territory; males cannot
sting, nor do they make burrows. We do not recommend using insecticides
to control mining bees and ground nesting wasps; it is virtually
impossible to eliminate the population in a single season.
Adapted from the University
of Maryland Cooperative Extension, 1999
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
of Rhode Island Cooperative Extension provides equal program