(Used with permission, Sheryll Seagrave photo.)

European paper wasps, besides preying on other insects to feed their lar- vae, actively seek sugary substances for food. Their orange antennae is the easi- est characterstic to see that distinguishes them from native paper wasps. Their presence at hummingbird feeders can deter the birds from feeding.

EUROPEAN PAPER WASP, A WORLD TRAVELER, FINALLY ARRIVES IN WYOMING Perfectly at home in areas that give the wasp a competitive edge

Scott Schell habitations and damage ripening At Home Anywhere he European paper wasp (EPW) fruit in orchards and gardens and di- Several factors give EPW a com- Tmade its presence known in rectly affect native insect species via petitive edge. Wyoming last summer. predation. • Few enemies - So far, none of na- We are fortunate it took so long to Such severe losses of ripen- tive species of insect parasitoids arrive, as this insect has caused prob- ing fruit have been reported in fruit that attack native paper wasp lems in Colorado and Utah for over 15 orchards and vineyards that, in some populations recognize EPW as years. The wasp is now found in suit- cases, producers had no marketable potential hosts. able habitats over the world, except crops left. • The life cycle of the EPW has Antarctica. The wasp was first discov- The EPW might go unnoticed the overwintering queen becom- ered in the U.S. in Massachusetts in when first arriving in a state because ing active earlier in the spring the late 1970s. it looks similar to the native paper than native paper wasp species. EPW (Polistes dominula) is a wasp species. Later, when the EPW Frequently, multiple EPW queens member of the family Vespidae, in the populations increase, their “bad work together to found a colony order Hymenoptera and is native to behaviors” soon grabs people’s at- the next spring. This is in con- a large portion of the European and tention. The EPW will readily sting in trast to the single founding queen Asian continents. They will frequently defense of its paper nest when feel- life cycle of the native paper nest in close proximity to human ing threatened. wasp species. This gives EPW a

4 BARNYARDS & BACKYARDS competitive advantage over our of paper wasps and yellowjackets. native species. • The broad diet range of the EPW • Human activities create abundant also works in its favor. Insect prey, Prolific pests nesting habitats in towns and such as the caterpillars of but- suburban areas. The new queens terflies and moths, and the adults The European paper seek out protected overhangs, of many other insect species, are wasp at a Michigan wild- nooks, and cavities to start nests. all suitable prey. The EPW direct- The nests are created from the pa- ly competes with native insect life preserve went from per mache´-like mixture of wasp predators and song birds for food one observed colony in saliva and plant fibers. They don’t because it is such an effective 1995 to 62 percent of all have an outer cover like a bald- predator. the paper wasp colonies faced hornet or aerial yellowjacket Entomology Professor Whitney observed there by 2002. nest does for weather protection. Cranshaw of Colorado State University A cavity such as a bird nest box or no longer talks about butterfly gar- This makes EPW a threat the underside of the nest box can dening (the practice of growing host to our native species of be an ideal colony site. EPW can plants for the larva of butterflies) to paper wasps that have drive out insect-feeding bird spe- Master Gardener classes he teaches. long coexisted in balance cies from their nest boxes (such Such gardening is futile with arrival of as bluebirds and tree swallows). the EPW. with other native fauna. • This species ignores the wasp Such excessive predation might traps developed for native species be good news if you battle the (Photo by Kathy Keatley Garvey)

The European paper wasp is a voracious predator that preys on a broader range of insect species’ larvae and adults than our native paper wasps. Here is a European paper wasp attacking a Gulf fritillary butterfly.

WINTER 2016 5 Bill Rathburn photo

No western yellowjacket competitor

The scavenging, ground nesting, frequent stinging, and all-around nuisance western yellowjacket, Vespula pensylvancia, is not a competitor with EPW, so their population probably won’t be affected.

The addition of yeast to a mixture of damaged raspberries, Squirt soda pop, and a little dish soap as a wetting agent increased the catch from three European paper wasps to over 100 when it was placed at the edge of a Sheridan County raspberry patch. caterpillars of cabbage white butter- and lure the first workers to their concocted a bait mixture of damaged flies every year in your garden but sad deaths. This method will greatly re- raspberries, some yeast, Squirt pop, news if you enjoy seeing various but- duce the size of EPW population later water, and a little dish soap. The pres- terflies, such as swallowtails or fritillar- in the summer. ence of alcohol from fermentation in ies, around your town. The bait selectiveness of EPW the bait increased his catch rate of EPW significantly. He will be ready for Utah Wasp Wisdom was confirmed by a Sheridan County resident when, what he originally EPW this spring. Utah State University Extension thought were yellowjacket wasps, Hopefully, we will all be ready for has advocated management tech- started raiding his raspberry patch EPW for years to come as this world niques that help reduce the popula- traveler is here in Wyoming for the last summer. Wasps in numbers he tions of EPW to levels that mitigate long-term. their effects on the environment, had never seen before were damag- crops, and reduce the risk of stings on ing the berries but were not respond- humans. ing to conventional wasp traps. After Entomology Professor Diane a local news story informed him EPW Alston of Utah State University has was the likely culprit, he contacted found that homemade traps, or facto- me for confirmation of the identity ry-made traps, baited with fermenting of his wasps and suggestions for fruit juice lure EPW quite well. Start management. trapping early in the spring to elimi- Researchers have found that EPW nate emerging overwintering queens are attracted to fermentation, so he

The European paper wasp at right better be watching for Scott Schell. He is a University of Wyoming Extension entomologist and can be reached at (307) 766- 2508 or [email protected].

6 BARNYARDS & BACKYARDS