Pestology Blog

In this paper, the researchers wanted to use ants to track the spread of spotted lanternflies. Here’s a bit of background. If you live on around the northern half of the east coast, you have probably hear about the invasive spotted lanternfly. These colorful bugs are black, white, and red and may be coming to a town near you. In some areas where infestation levels are high, it may be impossible to walk down the street in July or august without seeing several of these in your path. You may also fall victim to their sticky honeydew covering your car parked under a tree for shade. But it takes some time for population levels to get this high. Identifying invasive species presence early can be key in preventing high infestation levels and preventing further spread.  

The researchers used a technique that takes advantage of this new technique called eDNA. This uses analysis methods to track environmental DNA that organisms shed into their environment. In the case of spotted lanternflies, they secrete honeydew which is known to contain their DNA, which is sometimes then consumed by ants. Ants seek out the honeydew for food and are prolific insects found in almost every environment. This all comes together for the researchers to ask the question if the spotted lanternfly can be located without actually seeing it by finding its DNA in the ants who consumed their honeydew.  

Well, this was something no one had done before so there were a few steps before an answer could be acheived. First they had to check if lanternfly DNA was present in the ants that lived nearby them. Next, how quickly and how much does that DNA degrade after being consumed aka would this show how recently the lanternflies had been there? And finally, what rates of the DNA present would indicate a SLF presence.  

After finding some sites of various infestation levels, they ran several trials to find these answers. They ran these trials in the lab and in the field to test out their ideas. In the lab, they fed field collected ants a known solution of spotted lanternfly honeydew and body parts and tested if it stuck around over increments of days up to five days. Ultimately, they were able to extract the DNA of the lanternfly from the ants in lab conditions to prove that the ants would carry it. 

Next up, in the field they sampled ants from locations of varying distance to the known infestation in sites in Salem and in Lynchburg using honey lure traps. They found the spotted lanternfly DNA in many ants that were nearby infested trees but not all. This proves that ants within a 50m radius of spotted lanternfly populations can prove presence of the infestation. The researchers have dubbed this method, antDNA. In reality, you would want to put out several traps across a broad area to get the best idea of the pest presence. This tracking method is easy to do in the field, inexpensive, and only requires analysis be done by a lab after collection. 

Image: Fig. 3 Distribution of honey-baited lure stations along the transects at the three field study sites, showing ant detection rates (number of lure stations with ants/total number of lure stations) and SLF DNA detection rates (number of lure stations with ants positive for SLF DNA/total number of lure stations with ant presence). At Lynchburg site 2 (c), the transect was curved along the edge of the parking lot due to traffic constraints.

While spotted lanternflies as an invasive species are of high concern in agriculture, they are also a pest in residential areas outside, and can occasionally wind up indoors. Knowing where this invasive species will spread to next and tracking that spread will be important to research efforts in stopping them.  While this project proves a concept for tracking the species, it may open doors to tracking other invasive species in the future. If we think big, this concept of eDNA or antDNA could be carried over to other pests and used to predict and track trends using the coordination between academia and PMPs.  

This research was funded by the Pest Management Foundation, NPMA’s charitable organization that raises funds for supporting important pest management research just like this. If you want to learn more about the PMF or make a donation, visit www.npmafoundation.org.