Monday, December 1, 2008

Meat Wasp Attack

According to a recent article in the La Jolla Light, a small group of children were attacked by "meat wasps" while exploring La Jolla Summit canyon last week. Because the wasps were so aggressive and the children were stung multiple times, it was originally assumed they were attacked by Africanized Honey Bees. Two of the children were taken to Rady Children's and Scripps hospitals for treatment , where they identified the insects as meat wasps.
Apparently, the children stumbled on a hive just before dusk, disturbing the insects and causing them to aggressively defend their territory. Although one 6-year-old was stung more than 50 times, all the children were fine - fortunately, none were allergic to wasp stings. They were able to run to a neighbor's house, who then called paramedics and washed away remaining insects.
The story ends well, but raises a few questions for residents of San Diego County. First, what are "meat wasps"? How common are they? And how might the attack have been prevented? 
In the western United States, there are two distinct types of social wasps: yellowjackets and paper wasps. Of the two, paper wasps are much less defensive and rarely sting humans. Yellowjackets can be more troublesome. The term "yellowjacket" refers to a number of different species of wasps.  The western yellowjacket  (Vespula pensylvanica - pictured above) is a ground-nesting variety, sometimes called a "meat bee." This is most likely the insect from the La Jolla story. Unlike other local wasps whose nests usually die out by the end of summer, the western yellowjacket continues its life cycle well into late autumn. These pestiferous wasps are the ones we sometimes see at picnics or outdoor eateries, because they are scavengers. They usually nest in  hilly areas - often using abandoned rodent burrows for their hives. While they are considered a useful pest because they help naturally control other more destructive insects, yellowjackets will protect their nest if they feel threatened. This seems to be what happened in La Jolla. 
The children probably did nothing wrong, but their encounter should serve as a learning experience for others in the area. If your children are playing in a canyon or undeveloped area, be sure they are wearing long pants, long-sleeved shirts and proper footwear. Apply the same precautions to yourself if you are hiking off trail. Be aware of sights and sounds that may indicate hive activity and avoid exploration near possible nesting sites. Tomorrow's quiz will look at the differences between bees, wasps and hornets. Give the quiz a try to test your knowledge of these stinging bugs and learn how to avoid them.

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