YellowjacketThere are two types of “social wasps” in our Sacramento pest control region: yellowjackets and paper wasps. Of the two, yellowjackets are more aggressive and dangerous to humans. Yellowjackets will attack if their nest is threatened or, less frequently, if someone tries to swat them away from a food source. Paper wasps are less defensive, less apt to sting, and shy of humans unless their nest is located near a traffic-way such as a door or gate.

Both yellowjackets and paper wasps start building their nests in early spring, when a single queen emerges from winter hibernation as the weather warms. From spring to late summer, they forage primarily for protein, usually in the form of other insects, to feed their growing colonies. Later in the summer and early fall, the colony may have grown to as many as 15,000 individuals. Large amounts of sugar are needed to feed the queens and workers, and this is when they become more troublesome to humans. It’s not uncommon for swarms of yellowjackets or wasps to aggressively forage around trash cans, dumpsters or human picnics and barbeques, where they may crawl into soda cans and sting when the unsuspecting victim takes a drink.

The most common type of yellowjacket found in our Sacramento pest control area is the ground-nesting western yellowjacket, (Vespula pensylvanica), sometimes called the “meat bee.” Other types of yellowjackets common to Northern California include Vespula vulgaris, often found in dead trees in foothill or mountain terrain, and the German yellowjacket (V. germanica), which often nests in houses in urban areas. Most types of yellowjackets have distinctive black and yellow stripes on the abdomen and have a very short narrow “waist.” Paper wasps are larger, about an inch long, usually black or brown in color with red or yellow patches, and have a long slender “waist” and long legs.

Yellowjackets may build their nests in abandoned rodent burrows or even inside the walls of houses, where a hole in the wall may result from the insects’ work to expand the next space. The nest contains rows of cells and is enclosed in a paper envelope the insect manufactures from wood fiber and saliva. Other types of yellowjackets build hanging nests beneath eaves or tree branches. Paper wasp nests, usually built under eaves or branches, also contain rows of cells but are open, with no paper covering. A nest normally contains no more than 200 individuals.

Mud daubers, which may be mistaken for yellowjackets or paper wasps, build nests out of hardened mud. Mud daubers are usually not aggressive and rarely sting.

For more information about yellowjackets, wasps and other stinging insects, feel free to call our experienced Sacramento pest control professionals at 916-457-7605.