APRIL
2014

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

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Check out these books by Tom Turpin:

Flies in the face of fashion

What's Buggin You Now?

 

 

 

04-24-14

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Ground Dwelling Bees


ground bee
Mining Bee (photo credit: Cheryl Mooreland)

I suspect that most people wouldn't consider bees and wasps to be some of their favorite insects. Of course, most people probably don't even have a favorite insect. But if they did, I guess it is probably a butterfly or maybe even a ladybug.

Bees and wasps are not the kind of insects that elicit warm, fuzzy feelings from humans. One of the biggest reasons for our dislike of bees and wasps is that these insects have the ability to sting. And being stung by insects is something that we humans don't relish.

So what are bees and wasps, anyway? Most dictionaries define wasp as a social or solitary winged insect that has a narrow waist. Bees are defined as any of several winged, hairy-bodied, usually stinging insects. Entomologists include both of these types of insects along with sawflies and ants in the order Hymenoptera.

Bees and wasps both have social and solitary species. Both types of insects have four membranous wings. The females of most bees and wasps can sting. So what is the difference between bees and wasps? Structurally, it boils down to two things: Bees tend to be fuzzier and more heavier-bodied than wasps.

There are other differences between bees and wasps. Bees generally are associated with collecting pollen as food for their young. So the hairs on bees' bodies are generally branched, which helps pollen stick to bees.

Wasps, on the other hand, generally do not use pollen as food for their offspring. Consequently, hairs on wasp bodies lack the branching feature found in bees. Some baby wasps are parasites within the bodies of other insects; others eat food such as spiders and insects that their mother captures for them.

Because of the association with pollen, bees tend to be around in the early season when many plants are producing pollen at a high rate. Some of the more noticeable, larger wasps are social insects, meaning there is a queen and workers in the nest. Yellow jackets, paper wasps and bald-faced hornets are social wasps. A mated queen starts a social wasp nest each season, and insect numbers in a nest reach peak numbers in the fall of the year.

Two species of social bees exist in the U.S.—the honey bee and the bumble bee. Honey bees live in perennial colonies, and bumble bees live in a colony that exists for only the summer. Both of these social bees can have large numbers of individuals in a colony.

But, occasionally in the early spring, a few people encounter a great mass of small bees flying around near the ground. These are not social bees even though they appear in the same area in great numbers. Such bees often turn out to be a type of ground nesting bee. Some are called plasterer bees, and some are called mining bees, but all nest in the ground.

Because these solitary bees, including those that nest in the ground, gather pollen they play an important role in plant pollination. This relationship has garnered renewed attention in recent years as more and more people recognize that honey bee colonies are not as numerous as they once were.

Another difference between bees and wasps is that all bees are defensive stingers. That means they use their stinger to protect themselves. Wasps can also use their stingers in self-defense, but some species use the stinger to paralyze prey, a process that is defined as an offensive sting.

In general, the ground nesting bees only sting if someone grabs them or they get caught in clothing. That is why I tell people to leave the bees alone and they will not sting.

That was my story a few years ago when I got a call to a local establishment that was going to host a wedding the next weekend. The problem was that a large group of ground nesting bees was zooming around the lawn and flower beds. I explained to the prospective bride and groom that the bees were not likely to sting—and, besides, they are important pollinators. The next week I noticed a picture in our local newspaper showing a wedding party and a nice hand-lettered sign that read: "Please don't pet the pollinators!"

 

 

Writer: Tom Turpin
Editor: Olivia Maddox