As Yellow Jacket Population Peaks, So Does Danger Of Stings

Published: October 27 1999

Category:Environment, Research

GAINESVILLE—University of Florida researchers say yellow jacket season is at its peak and warn parents to be particularly careful about keeping children away from the territorial insects’ nests.

Earlier this month, UF entomologist Phil Koehler and two graduate researchers helped Alachua County school officials track yellow jackets from a schoolyard back to a nest large enough to house 100,000 of the aggressive wasps.

The insects had been stinging children almost daily for several weeks as the children ate lunch in the school courtyard. Unlike pollen-loving bees, yellow jackets dine on meat and sugar and were attracted by the lunches, juices and sodas the children brought to the courtyard.

“It was so bad at this school that if a child threw a soda can into the trash they had to run,” said Koehler, an urban entomology specialist with UF’s Institute of Food and Agricultural Sciences. “The principal said the day after we destroyed the nest was the first day since school started without a child being stung.”

And in August, two Pasco County boys were hospitalized after falling on a yellow jacket nest in a wooded area. One boy was stung 271 times.

Koehler said the venom in 300 yellow jacket stings is enough to kill a child, regardless of whether the child is allergic to insect stings. For people with allergies, a single sting is enough to cause an anaphylactic reaction, including a drop in blood pressure and difficulty breathing, or even death.

Yellow jackets can inflict multiple stings, unlike honeybees, which can sting only once. They are commonly mistaken for bees and, according to some estimates, account for nearly 98 percent of all stings.

Koehler recommends that children with insect venom allergies leave a sting kit with the school nurse and wear a medic alert bracelet, especially this time of year.

In Florida, most yellow jackets build nests underground, making it easy for a child to stumble upon a nest before recognizing the danger. The population of yellow jackets is particularly high in the fall because they’ve had all summer to reproduce, Koehler said.

“We’re seeing huge nests this year,” Koehler said.

“It turns out that schools are a great location for yellow jackets to thrive because they are a constant source of food scraps and sweets,” Koehler said. “Hundreds of kids are getting stung every day throughout Florida.”

To avoid injury in destroying a nest, Koehler suggests using a pest control company and asking about the company’s expertise. While many pest control operators have trouble finding nests to destroy them, others specialize in locating and treating the nests.

Koehler and his assistants found the nest they destroyed by following the insects, which sounds simple but requires knowing a few things about the insects.

First, the team baited several yellow jackets with a mixture of cola and corn syrup. When the yellow jackets were full, they made a beeline for their nest. Since they will fly over the highest objects in their path, binoculars were needed to keep the insects in sight over a tree line. After they crossed the tree line, the insects flew in a straight path toward the opening of the nest, allowing researchers to zero in on it.

The nest opening was sprayed with a dust lethal to yellow jackets. The yellow jackets tracked it into the nest over the course of a day, eventually contaminating the whole nest.

Koehler said it is important to distinguish between yellow jackets’ flight patterns when foraging for food and when traveling back to the nest. Foraging flight appears random, he said, and the flight path only straightens out when yellow jackets are returning to the nest.


Cindy Spence
Phil Koehler

Category:Environment, Research