Back to Nature (Published on - April 26, 2007)
Spring brings about many beautiful things in life, but it is also that time of year when my e-mail box is jam-packed with requests for information concerning stinging wasps. And although entomology isn’t my academic area, like most of you, I’ve certainly had enough experience with these little critters, in fact I’m extremely allergic to wasp and bee stings.

The University of Florida Department of Entomology and Nematology paper on yellowjackets states there are only two of the sixteen North American species of Vespula (true wasps) known from Florida.

“These are the two yellowjackets: eastern yellowjacket, V. maculifrons, and the southern yellowjacket, V. squamosa.

One species of Dolichovespula is also present: the baldfaced hornet, D. maculata (Linnaeus). The baldfaced hornet is actually a yellowjacket. It receives its common name of baldfaced from its largely black color but mostly white face, and that of hornet because of its large size and aerial nest. In general, the term “hornet” is used for species that nest above ground and the term ”yellowjacket” for those that make subterranean nests. All species are social, living in colonies of hundreds to thousands of individuals.”

Commonly asked questions are: “Why are there so many wasps this year?” and “Why do they seem so aggressive?” For answers to these questions, I made a trip to the Pinellas County Extension Service, University of Florida, Institute of Food and Agriculture Sciences, Department of Entomology and Nematology.

“Why are there so many wasps this year?”

Most of the complaints I’ve received concerned the yellowjacket, Vespula spp.

Since the past couple of winters have been very mild in our area and most of the southern USA, we have experienced an abnormal abundance of yellowjackets and other insects. The yellowjackets nest in colonies, in large, football-shaped nests that most often are located in and on the ground. They don’t dig these nests, but are opportunists taking advantage of old burrows, for example previously excavated by rodents, armadillos and rabbits. I was told that nests have been discovered in Florida as large as an old washtub! This is unusual, however, because normally the winter cold kills off the majority of the residents. When spring arrives, the queens emerge and the nest building begins again.

“Why do they seem so aggressive?”

This insect is very aggressive when defending itself or its nest. “They’re social insects and their colonies develop in a similar way. Adult females make up two castes: queen or fertile females which lay eggs; workers or sterile females which feed larva and may lay eggs without mating if the queen dies during the season. In the fall, queens and males leave the nest and mate. The male dies and the surviving queens (during normal winters) hibernate in cracks of rocks, under bark of trees, in buildings, or in the ground. In the spring the queen comes out of hibernation and builds a nest with a few shallow cells. An egg is laid in each cell and these hatch into worker larvae in two or three days. The queen feeds these larvae which develop in 12 to 18 days and spin cocoon caps over the cells and change into pupae. After the first brood emerges the queen resumes egg laying. The workers take charge of the nest, enlarging it and caring for the new larvae.”

Stinging or venomous insects and related pests

The problem with this arrangement in Florida is that the queen and workers for over the last couple of years didn’t hibernate or die, so we are experiencing the results of this continuing building and growing of these nests which the male wasps feel necessary to defend at all costs.

One suggestion to help curb this situation was very timely during this season in Florida; pick up the fallen fruit from our yards. Wasps are attracted to sweet nectar, ripened fruits, sweet drinks and generally all those wonderful things we love at an outdoor picnic. Covering these items may help when outdoors.

As most of us know, pesticides are best applied at night time when the insects are less likely to attack, but protective clothing should always be worn. When there is any concern of an adverse reaction to a sting, you’d obviously be better having this job handled by a professional.

“For below ground nests, (such as the yellowjacket) locate nest and mark area so it is easy to find after dark. Use a flashlight covered with a red cellophane paper so wasps stay in their nest. At night, puff dusts into nest entrance and immediately throw a shovelful of moist soil over entrance. Be careful not to step into nest.”

In spite of the “bad side” of yellowjackets, these insects are actually beneficial “because they attack and destroy many harmful insects found around the home and gardens, such as: house flies, blow flies and various caterpillars.” This is little comfort to you when you’re trying your best to enjoy the best season in Florida, with company, at an outdoor party, while being attacked by aggressive yellowjackets … the price we pay for such beautiful weather. This is why it is so important to locate those nests “before” your celebration and eradicate them.

I hope this has briefly answered a few of your questions. For more detailed information and expert advice visit your local extension office for pamphlets and printed documents. You will also discover a wealth of other information at your fingertips; gardening tips, putting up the fruits of your labor for next winter and so on. The extension office personnel are quite knowledgeable and very willing to help you with a variety of topics. Or visit The University of Florida Department of Entomology and Nematology Web site:

Karen can be reached at

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