I was running on a popular trail in Woodside, Skyline Ridge. In this race, approximately 7 out of 10 people I talked to also were stung-- some through clothing and others victimized by repeated stings inside their shirt. Yellowjackets are a kind of short, squat wasp that often builds nests out of abandoned rodent holes. It is during fall they are most aggressive.
A couple of years ago I was stung at the Marin Farmers Market as a plodding horse (with my kid on it, of course) disturbed denizens of an underground nest. I found out I am particularly vulnerable. My foot was swollen for over a week. Worse, some may be susceptible to anaphalactic shock.
The episode sparked my curiosity of the feisty, furry creature. Why the attitude?
It is a combination of several things that angers them in the fall.
Yellowjacket nests are constructed in the spring by a solitary fertile female. She cares for about 30 larvae all by herself. When they hatch, they take over constructing the nest. The queen yellowjacket continues laying more eggs. These insects feast on flies, tree sap, fruits, caterpillars, in addition to excess trash, especially sweet-smelling foods and meat left in the open. The adults chew up protein and reconstitute the food to feed the larvae. The larvae in the nest then secrete a sugary material eaten by adults. By the end of summer any one colony may reach a population of 4000 workers.
During autumn, the larvae stop secreting the sugar. The fertile male and female bees leave the parent colony to mate, whereupon the males soon die. What's left is a colony of thousands of worker adults suffering a lack of sugar. Kind of like your toddler's later afternoon inexorable demise. So if in their addled state yellowjackets hear vibrations in the ground, see rapid movement, or sense a pheromone alarm emitted by other guard workers, they will become especially aggressive and territorial.
Bzzzzzz. China Camp is a good place to find yellowjackets.
By the start of winter, all the yellowjackets in the colony die, except for the newly mated females, who fly off to survive the winter all on their own-- perhaps in a tree hollow or dry eave.
Today I received a call from our teacher at MdTL. My son was playing four-square in the play yard and got stung by a yellowjacket very close to his eye. We put a cold compress on him and watched for signs of difficulty breathing. His cheek is quite swollen but his air passage is clear. I get to tell him all about the yearly cycle of a very sociable animal. A teachable moment. He's fine, although he looks like he took a fastball to the face. Wait-- that is kids' safety hazard #37,118.
Post by IAN
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