Solitary Bees of Springtime

by Andrea Laine, EMGV

Say ‘bee’ and many of us think bumble or honey. But at this time of year we are apt to see ground-nesting bees out and about our landscapes, visiting the same early spring flowering plants that a honey bee might pollinate.

Ground-nesting bees are native solitary bees that nest individually in polyester-lined tunnels or burrows at least six inches deep in warm, dry ground. Reflective of this behavior, they are also called mining bees or digging bees. They are more likely to nest in areas with exposed soil and sparse vegetation, not dense turf or mulched beds.

MiningBee_M.Bertone
There are many species of bees that nest in the ground and they range in size and color. Pictured here is an adult mining bee. Photo by M. Bertone. 

 

TBilleisen ground bee damage
Evidence of ground nests can resemble tiny ant hills. Photo by T. Billeisen.

A hospitable patch of ground is likely to house a number of solitary tunnels, thus giving the impression at times of a small swarm of low-flying bees. But these bees are not aggressive as they are not defending a hive (as honeybees and bumblebees would be). And, as is the case with all bees, males cannot sting.

For two to four weeks in mid to late spring, females collect pollen and nectar to bring back to the nest. With it they form a ball in the side of the tunnel. They lay a single egg on the ball and when it hatches, the larva feeds on the pollen and continues to develop until the following spring when it emerges from the ground as an adult bee and goes forth to build a new nest.

Solitary bees are beneficial insects: They pollinate plants and their burrowing behavior is hardly noticeable and does no damage. On the contrary, it helps aerate the soil.

 

Sources & Further Reading

Matthew Bertone, Plants, Pests and Pathogens, Feb 26, 2019

https://www.turffiles.ncsu.edu/insects/bees-in-turf/

https://caldwell.ces.ncsu.edu/2014/06/ground-digging-bees/

http://www.gardening-for-wildlife.com/ground-bees.html

 

 

What’s that Bug? (aphid eaters edition)

Most gardeners know that ladybugs have a huge appetite for aphids. Everyone recognizes adult ladybugs, but what about their larvae and pupae?

When a ladybug larva hatches from its egg, it looks like the one on the left (ready to dine on lots of aphids):

Photo: NCSU Beneficial Insect Thumbnail Gallery

After a couple weeks, the ladybug enters the pupal stage. It attaches to a leaf and now looks like this:

ladybug pupa

Photo: Peggy Yehl

Once metamorphosis is complete, the adult ladybug emerges from the pupa skin. The ladybug will dry for a few hours, and then it is ready to feed on more aphids. http://www.ca.uky.edu/entomology/entfacts/ef105.asphttp://www4.ncsu.edu/~dorr/Insects/Predators/Ladybeetles/Harmonia/Harmonia.html

This is a Syrphid Fly (also called Hoverflies or Flower Flies)

syrphidclose

Photo: Debbie Roos, Extension Agent (for more, see http://growingsmallfarms.ces.ncsu.edu/growingsmallfarms-syrphid/ and http://www.cals.ncsu.edu/course/ent425/library/spotid/diptera/families/syrphid.php)

Although their coloration mimics bees, they do not sting. Adults feed on nectar and pollen, but the larval stage eats aphids. Adults lay eggs near aphid infestations. Pupae are formed on plants or on the ground nearby.

IMG_7996

Photo: Peggy Yehl

The Green Lacewing is another type of insect that feeds on aphids. Adults mainly feed on nectar and pollen, although some can be predators. Adults have an unpleasant smell when touched.

Lacewings lay eggs on plant foliage. These eggs are attached to a long, thin stalk. The larvae, which feed exclusively on small insects, are sometimes called aphid lions. Pupae attach to the backs of leaves.

Photos: NCSU IPM (top), John Meyer (bottom)

http://www4.ncsu.edu/~dorr/Insects/Predators/Lacewing/green_lacewing.html#

It is helpful to learn to recognize the different stages in the life cycle of beneficial insects. Look for them when you’re scouting your garden for pests!