Wasps become a little more noticeable in the fall

 
Posted10/15/2018 6:00 AM
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  • German yellowjackets nest in the ground or in cavities such as walls, and they vigorously defend their nests from even the slightest perceived danger. These two were busy at their nest in LeRoy Oakes Forest Preserve, St. Charles.

    German yellowjackets nest in the ground or in cavities such as walls, and they vigorously defend their nests from even the slightest perceived danger. These two were busy at their nest in LeRoy Oakes Forest Preserve, St. Charles. Courtesy of Pam Otto

  • A non-native European paper wasp on non-native Queen Anne's lace. The European paper wasp is a concern to ecologists because it aggressively competes with native wasps. An additional concern is its predation of monarch caterpillars.

    A non-native European paper wasp on non-native Queen Anne's lace. The European paper wasp is a concern to ecologists because it aggressively competes with native wasps. An additional concern is its predation of monarch caterpillars. Courtesy of Valerie Blaine

  • Native wasps are excellent pollinators. This bald-faced hornet is sipping nectar from a stiff goldenrod plant at Muirhead Springs Forest Preserve in Hampshire -- and getting dusted with pollen.

    Native wasps are excellent pollinators. This bald-faced hornet is sipping nectar from a stiff goldenrod plant at Muirhead Springs Forest Preserve in Hampshire -- and getting dusted with pollen. Courtesy of Valerie Blaine

  • A look inside a bald-faced hornet nest reveals multiple chambers for the larvae. The queen resides in the interior of the nest.

    A look inside a bald-faced hornet nest reveals multiple chambers for the larvae. The queen resides in the interior of the nest. Courtesy of Valerie Blaine

  • Bald-faced hornets' nests are securely attached to branches, often high above the ground. This nest was well hidden at Tekakwitha Woods in St. Charles during the summer, but easy to spot when the leaves had fallen.

    Bald-faced hornets' nests are securely attached to branches, often high above the ground. This nest was well hidden at Tekakwitha Woods in St. Charles during the summer, but easy to spot when the leaves had fallen. Courtesy of Valerie Blaine

Last summer, I was on a mission to photograph native bees as part of a statewide monitoring program. After tramping around prairies with my camera, I'd download the photos -- only to find that lots of my bee shots were photo bombed by wasps.

The wasps that sneaked in my photos were part of a large group called the solitary wasps. They diverted my attention enough to inspire my August column.

As cool as solitary wasps are, there's a group of equally fascinating wasps called social wasps. These notorious wasps begin to create problems in September. People ask me in a panic every fall, "What can I do about these bees? They're everywhere!"

Time for "Wasps: The Sequel."

First, let's not blame bees. Nine times out of 10, the criminal in question is yellowjacket, which is a wasp. Yellowjackets are the bad boys of the insect world -- only they're not boys. The ones we see are sterile females. At the slightest provocation, they will sting anything and everything. Your mere presence -- or, the very fact that you exist -- can provoke a yellowjacket.

Making matters worse, these ill-tempered insects can sting repeatedly. Unlike bees, yellowjackets do not lose their stinger once plunged into a victim's skin. They're armed with fully automatic hypodermic needles.

Yellowjackets are around all summer, but we tend not to notice them until fall. By this time of year, their colonies experience a population explosion. Some colonies comprise thousands of individuals. That's a lot of mouths to feed.

The female workers are desperate to provision the colony. Their mainstays, protein-packed caterpillars and grubs, are harder and harder to find by September. They have to search longer and harder.

To fuel their foraging, they turn to sugar. (Why not?) Garbage cans and picnic areas are a bonanza for the desperate wasps. Apple cores, candy wrappers, pop cans -- just about any sugar fix will do.

The majority of the yellowjackets we see are German yellowjackets, or Vespula germanica. This aggressive, invasive species hails from Europe. It's purported to have arrived in Montreal in the 1960s and is now present throughout the world. Its notorious reputation follows it wherever it goes.

Not all black-and-yellow striped insects should be judged by the behavior of yellowjackets, nor wasps in general. Bald-faced hornets -- which are wasps, and not true hornets -- are among the most misunderstood native insects.

Cream markings on a black background make this insect look bald. In fact, they're fuzzy, if you look closely. The queen, whom we rarely see, is about one inch long. She remains deep inside the nest laying eggs. You're more likely to see the workers who are out and about foraging for food.

These gals are a little over a half an inch long. Despite their bold markings, bald-faced hornets go about their business most of the summer, undetected by humans.

And just what is their business? It's not hunting humans to sting. They really want nothing to do with humans. Bald-faced hornets are predators of other insects. They eat live prey, including yellowjackets, which is a boon for us. Another plus is that they drink nectar, thereby pollinating a variety of flowers.

Bald-faced hornet nests are architectural wonders. When not foraging in the summer, the female workers are chewing wood, mixing it with saliva, and creating paper. They fashion this paper into a large, globose structure with hundreds of hexagonal cells to house the ever-increasing number of larvae.

By fall, the football-shaped nests can be two feet long and 18 inches across. Choice locations for nests are usually tree branches from three to 60 feet above the ground.

When the leaves begin to fall, the nests become noticeable. The females are foraging at full tilt, and people begin to spot them coming in and out of the nest.

Unfortunately, a common reaction is to panic and grab a can of spray. If the nest is high and you're not running into it when you walk out the door, it's best to leave it alone. Let these social wasps do their thing. They're beneficial, native insects, and they will only sting you in self-defense.

Another type of social wasp is the paper wasp. As the name suggests, these wasps also masticate wood to create nests. This high-density housing is often under the eaves of man-made structures. The European paper wasp is common in Kane County. Unfortunately, this nonnative insect often preys on monarch caterpillars and, in some areas, the European paper wasp is displacing native wasps.

The world of wasps is a mixed bag. Whether solitary or social, they play crucial roles in ecological systems. Nonnative wasps are a challenge, and should be discouraged. Native wasps provide valuable ecosystem services. When it comes to bald-faced hornets, a live-and-let-live course is the best to take.

•Valerie Blaine is the environmental education manager for the Forest Preserve District of Kane County. You may reach her at blainevalerie@kaneforest.com.

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