Monitoring for Emerald Ash Borer using Cerceris fumipennis nests

Figure 1 . Colour markings painted onto a female Cerceris fumipennis.

By marking the wasps and nests, a human monitor at a colony can quickly and easily track the flights and successes of various wasps. Each wasp can be easily and safely handled as they rarely (never in our experience) use their stinger in defence. Wasps can be individually marked with a small dot of non-toxic paint dabbed on the top of the thorax (Fig. 10) to facilitate the tracking of individual wasps and to allow the recording of foraging times and range. Nests can be marked and regulated using a “collar” made using a small 2 x 6 cm plastic or cardboard file card and a standard hole-punch. Holes are made on each end of the tab and it is secured over the nest entrance with a golf tee driven through one hole (Fig. 11).

The collar’s hole is large enough to allow wasps without prey to pass through uninterrupted but is small enough to prevent a female returning with prey from squeezing through. In response the wasp (reluctant to release its prey) will buzz and claw at the collar’s opening, alerting a human monitor to the wasp’s return (Fig. 12). The bright green EAB adult prey is

Figure 2 . Materials need to make a ‘collar’, for placement over the entrance of a Cerceris fumipennis nest.

so distinctive it can be visually identified and then the collar can be moved to one side to allow the wasp to pass into the nest with her prey. Once the female wasp has entered, the collar is repositioned over the entrance and is ready for the wasp’s subsequent exit and next successful return.

Prospects for the future

Biosurveillance requires the predator species to be available at all suspected areas of prey infestation. Naturally-established colonies of C. fumipennis, while widespread in eastern North America, are only capable of foraging over a limited area and it is unlikely that there are enough well-placed natural colonies to use this as a surveillance tool within Canada and the US. Consequently, the development of mobile transplant wasp colonies could vastly improve the value of C. fumipennis as an EAB surveillance tool. Research is currently being conducted in this area.

Figure 3 . This female Cerceris fumipennis, (returning with prey) is unable to pass though the 'collar's' hole to her nest. This wasp has caught a male and female EAB in copula. The female beetle has been paralyzed by a sting from the wasp. The male beetle was not stung but is reluctant to break copulation – to his ultimate demise.