Bees in Their Burrows

A very common, and often frantic, question we get asked is “what are all those little bees that are flying around my lawn?” For many of us there are two kinds of bees – honeybees and bumblebees. But, the fact is that there are thousands of different kinds of bees in the world, and a great many different kinds in North America. It is only the honeybee and the various species of bumblebees that are “social” bees, in which a Queen bee begins a colony, lays all of the eggs, and generally runs the society with her contingent of worker bees handling the tasks of building and enlarging the nest area, finding food, and tending to the developing eggs and larvae. It is an unfortunate side effect of misunderstanding that the second question commonly asked about these little bees is “how do I get rid of them”, for they are beneficial to your garden and should be encouraged.

All of the other kinds of bees you’ll find in North America are referred to as “solitary” bees, meaning they do not live in organized social groups. You may see large numbers of them milling around over your lawn or garden, but each one will be acting independently to create a place for her offspring to live. One of the most noticeable of these wonderful solitary bees is the Carpenter Bee, but we will cover that in a separate article on BugInfo. Carpenter Bees are as large as bumblebees, and some species are a bit larger, and they are usually a shiny black or blackish green color. Some kinds seen in Hawaii, Florida, or Arizona may be over an inch and a half long and quite frightening to see if you do not know its nature. Getting a sting from a solitary bee is not impossible, of course, because the females are equipped with a well developed stinger. But, without a colony, a queen, and a nest full of larvae to care for there is little instinct to sting a person or animal that gets close to them. Generally speaking you are at risk of a sting from a solitary bee or wasp only when you directly threaten that insect. This may occur if it happens to be in clothing that you put on, or if you were to pick it up or rest your hand on it.

The solitary bees we will discuss in this article are thosethat may create tunnels in the soil. We recognize the difference between beesand wasps, and yes indeed there are a number of solitary wasps that also burrowinto the soil for the benefit of their offspring, and these will be covered inseparate articles as well. Included with the wasps will be sand wasps, diggerwasps, and the enormous Cicada Killer wasps found in the southern and easternstates in the U.S.Our first instinct, perhaps, is always to kill a bee or wasp simply because wemay know it is capable of stingingus. However, by learning more about these insects we begin to realize that ourlandscapes may actually benefit from their presence, and with luck sometolerance will develop as we appreciate their hard work.

The bees we will cover here belong to these families:
  • Anthophoridae – the digger bees or cuckoo bees•Andrenidae – the mining bees
  • Halictidae – the sweat bees or alkali bees
  • Megachilidae – the mason bees and leaf cutting bees
  • Colletidae – the plasterer bees
Most of these small and often very colorful bees have a few things in common. Depending on the species they may nest in the soil or they may choose some cavity in wood or some other convenient place. On BugInfo we have a separate article on just the Leaf Cutting Bees, and hope you will take a minute to read that as well. These industrious little bees make a tube with sections of leaves that they shear from plants in your yard, and then place an egg and a small stash of food in cells in the tube so their larvae will survive that early stage of its life. You may find these tubes in the most curious places during the springtime when the bees are active.

The kinds that dig burrows are industrious little bees. The typical life cycle finds the adult bees most active in late spring and early summer, flying rapidly over the soil. The female does the work by digging down into the soil for a few inches, creating a narrow tunnel and piling the dirt at the surface. She then digs horizontal side tunnels that lead to small chambers that will house her offspring. In each of these small chambers she builds a small pile of pollen and nectar, and then deposits an egg next to that food. She then seals off that cell and proceeds to the next one until she has deposited all of her eggs. Inside the chamber the eggs hatch and the larvae proceed to feed on the food supply their mother has left them. They develop through several stages for a few weeks and then transform to the pupa stage. This in turn develops to the new adult bee, and the bees then spend the winter inside their chambers in the soil.

With the small size of these bees their digging and the associated dirt piles may go unnoticed, but when you have a swirling display of dozens of the male and female bees flying around in your yard you are suddenly aware of them. The male bees are incapable of stinging and the females are highly unlikely to do so. Given the beneficial nature of bees, with their role as pollinators of plants that produce our food, the best course of action now is to stand back and enjoy the fact that these bees have chosen your yard for their breeding grounds. There is no reason to kill them or discourage them, and your landscape is better off having them there. If children are playing in the area they should be educated on exactly what these insects are, and that they should not try to handle them. The more we can understand nature around us the better off we will be, and the healthier our gardens will be. There is a potential for some damage to occur to a lawn if dozens of the bees are working in the same area, with their individual tunnels near each other but not connected. But, the benefits generally outweigh the problems, and the damage normally is limited to just little piles of soil that can quickly be raked smooth.

The bees in the families Andrenidae and Anthophoridae usually are soil nesting kinds, and there are over 1200 different species of bees in the Andrenidae in North America. The bees in the Halictidae often are extremely colorful, being very hairy with light bands around their abdomen or fairly hairless but a brilliant metallic green or blue. The mason bees, in the family Megachilidae, are much larger, and while they may be seen around wet dirt areas they are there only to gather the mud needed to create chambers for their offspring to live in. These bees prefer to find holes in wood or plants, including hollow spaces in reeds or bamboo, and establish the nest area there. Recognizing their benefit you may even wish to attract them to your yard, and provide some appropriate nest sites by drilling holes in wood that you leave outside.

Finally, the plasterer bees in the family Colletidae will also be found creating brood chambers in the soil, and with over 120 different species of plasterer bees in the United States it is very possible you may see them in your yard. The female, as with the other groups, does all the work of creating the tunnels and chambers and provisioning them with a clump of pollen and honey mixed together. The habit of the female of smoothing a saliva mixture over the walls of the chambers is what gives them their name of “plasterer” bees. While they are not social bees and do not share these chambers with each other, there is no animosity for hundreds of them to be working close together in the same patch of soil.

With this brief look at some of the solitary bees we commonly find in our landscapes we hope you will develop that understanding of them and a tolerance for allowing them to stay. They are doing almost no damage to your landscape, and ultimately provide great benefit with their pollination of flowers and even their burrowing in the soil, loosening and opening it for better aeration and water movement. There is no reason to kill or discourage these little bees, and many reasons to enjoy them.