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Wasp Watchers: Biosurveillance of EAB

Jennifer Schultz, Wasp Watchers Program Coordinator

The University of Minnesota Extension has started a new program called Wasp Watchers that engages citizen scientist volunteers to help detect Emerald Ash Borer infestations throughout Minnesota. With the help of a harmless, native wasp, Cerceris fumipennis, volunteers can conduct biosurveillance for the Emerald Ash (EAB) and help with early detection of this invasive beetle that has destroyed tens of millions of ash trees in over 20 states.

The smoky winged beetle bandit, Cerceris fumipennis is a native, solitary, ground-nesting wasp that specifically hunts beetles like EAB. This harmless wasp is not known to sting people, even when handled. Females forage for beetles in trees and bring them back to underground nests as food for their offspring. This wasp has been used in over a dozen states as a biosurveillance tool for EAB detection. Biosurveillance uses one species to help detect the presence of another species. In this case, the beetle bandit wasp helps us locate areas where EAB is found. Early detection is critical for the management of this invasive beetle.
This small wasp preys on EAB and related beetles. By monitoring
their nests and watching what beetles they capture can help
determine whether EAB is in the area. Photo: Jeff Hahn, UMNExt

The process is simple: we search for beetle bandit nesting sites and monitor the type of beetle prey the wasp are capturing. Conveniently, these wasps prefer nesting in sandy, compact soil often associated with human disturbance. We’ve found that one of their favored habitats is along the infield edges of baseball or softball fields—especially fields that are not used frequently with some encroaching vegetation. We need volunteers to search their neighborhood ball fields to find Cerceris fumipennis sites. Once these sites are located, volunteers can help monitor the wood boring beetles that the wasps capture.
Infrequently used ball fields are a great place to look for
Cerceris fumipennis nests.  Photo: Jeff Hahn, UMNExt

An observer can easily watch a wasp colony (remember, they don’t sting people) and “steal” beetles from the returning wasp by simply using an aerial net to capture the wasp carrying its prey. When startled, the wasp drops its beetle prey and the beetle can be retrieved and collected by volunteers. If EAB is present, the wasp will find it for us!

Help us find more Cerceris wasp nesting sites. Currently we have around 25 confirmed sites, but we need many more. Each known nesting site is another location where we can monitor for the presence of EAB. So the more sites the better! Volunteers search your community’s ball fields for new Cerceris fumipennis sites. This takes very little time—approximately 15 minutes per ball field. Volunteers walk the border of the infield/outfield; where the grass meets the sand searching for nesting holes. After scouting out the ball fields, volunteers record their findings online on the Wasp Watchers website.
Two Cerceris fumipennis nests.  Photo: Jennifer Schultz, UMNExt

Once Cerceris nesting sites have been confirmed in your community, we need volunteers to adopt a site. They will then monitor their adopted site by visiting it 4-6 times in July and early August for 1-3 hour intervals. While at the Cerceris site, volunteers will intercept the foraging wasp to capture her beetle prey. Dropped or abandoned beetles are often found near nesting holes, too. These wood boring beetles (buprestids) will be collected and will be sent to the University of Minnesota for identification. Data on the beetle collection will be entered into our online database as well. However, if you suspect you have found Emerald Ash Borer, you should contact us immediately.

Wasp Watchers
“Whack a Wasp” video

Jennifer Schultz, Wasp Watchers Program Coordinator

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