Scavenger Yellowjacket Wasps

Scavenger vs. predatory yellowjackets

Of all the yellowjacket wasp species in the world just three or four account for the majority of problems with these otherwise beneficial insects. These species are listed in the table below along with the regions where they are found. Two of the most troublesome species worldwide are the common yellowjacket (Vespula vulgaris) and the German yellowjacket (Vespula germanica). Both are highly invasive and pestiferous. The other two troublemakers, the western and eastern yellowjackets, are more regional in occurrence.

The one characteristic that distinguishes pest yellowjackets from non-pest species is that pest species have adopted a scavenger habit wherein they supplement their normal diet of live prey with scavenged (dead) food. This behavior has two consequences: scavenger species make larger nests and foraging worker yellowjackets come into contact with people more often when there is exposed food outdoors.

Larger, more dangerous wasp nests

There is evidence that the scavenger habit adopted by these few species has allowed them to be more successful ecologically. The scavenger species tend to build larger nests that house many more workers than their predatory cousins. The scavenger habit may also allow these species to spread more rapidly into new geographical regions. The common yellowjacket and the German yellowjacket are rapidly expanding their ranges worldwide.

Contact with people

Scavenger yellowjacket species are also more likely to come into contact, and conflict, with people whenever there is exposed food outdoors. Scavengers are common around garbage and rotting fruit as well.