Pest Management Professional, September 2010

Stinging Insects Comparison of Vespula and Polistes species The best way to distinguish European paper wasps from yellowjackets is to focus on body design rather than the black and yellow colors alone Continued Confusion Here are tips to determine the difference between the European paper wasp and yellowjackets By Gerry Wegner Contributor A lmost three decades have passed since the European paper wasp Polistes dominula was first introduced to the continental United States Since then the wasps range has increased to include most of the contiguous 48 states and in some cases appears to be outcompeting native paper wasps Polistes species According to taxonomists the wasp has undergone a sex change in name only the gender of the species name has been changed from the Latin masculine dominulus to the feminine dominula Despite the press the European paper wasp has received throughout the years within the structural pest management industry technicians and sales associates particularly those in training continue to confuse this insect with yellowjackets Vespula species P dominula and most yellowjackets have black and yellow markings on their bodies So what are the differences PMPs can use to distinguish these wasps First most yellowjackets construct concealed nests Those that dont the aerial nesting yellowjackets Dolichovespula species have inverted pear shaped nests attached to the branches of trees and shrubs or protected recessed surfaces of structures Yellowjackets protect their developmental cells inside a round multilayer paper maché envelope Paper wasps construct umbrella shaped paper maché nests with the developmental cells exposed although the nests may be protected e g beneath cedar shakes eaves gutters porticos awnings light fixtures deck handrails grill covers behind shutters and in openended pipes and mailboxes The best way to distinguish European paper wasps from yellowjackets is to focus on body design rather than the black and yellow colors alone Paper wasps have a more elongated pedicel waist Add to that the conical shape of the first gastral segment of the abdomen Yellowjackets are short waisted The first gastral segment of the abdomen is wide where it abuts the thorax Furthermore paper wasps have long hind legs that are held rearward and downward during flight Yellowjackets have shorter hind legs relative to their body size The legs are held closer to the body during flight One color pattern feature of the European paper wasp that proves useful to separate this species from most yellowjackets is the presence of two oval yellow spots on the second gastral segment of the abdomen instead of a solid yellow band Knowing the difference between paper wasps and yellowjackets is useful when figuring out whether nests are present in or on structures where wasps are discovered indoors Yellowjackets of all castes may enter the living and work spaces of structures in abundance during late summer and autumn if theres a nest located in the exterior wall ceiling void attic or foundation In this case the nest should be located treated and if possible removed On the other hand mated female paper wasps may enter the occupied areas of buildings in large numbers during autumn winter and early spring via utility penetrations and gaps leading to overwintering sites in the exterior walls and cathedral ceilings of residences as well as the top floor ceiling voids of flat roofed commercial buildings In such cases the wasp entry points should be excluded and where possible one or more insect light traps can be placed and operated temporarily in the open areas above the drop ceiling panels of top floor workspaces PMP You can reach Wegner a Board Certified Entomologist and technical director at Varment Guard Environmental Services and ProGuard Commercial Pest Solutions at gerry wegner@ varmentguard com 90 PEST MANAGEMENT PROFESSIONAL SEPTEMBER 2010 www mypmp net