One solution for invasive spotted lanternflies? Your dog, study finds

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One solution for invasive spotted lanternflies? Your dog, study finds

The latest tool to stop the spread of invasive spotted lanternflies isn’t a powerful pesticide or a cutting-edge machine—it’s a good boy with an insatiable nose and a knack for tricks, Atmos reports.

A new study published in the journal “PeerJ” found that pet dogs can detect spotted lanternfly eggs, which can be removed and destroyed to help prevent the species’ spread. Detection dogs have been employed to spot the invasive insects before. But specially trained working dogs are expensive and in high demand. The state of Pennsylvania, for instance, just proposed a $145,000 annual budget to support its second-ever spotted lanternfly dog this year. The new study shows that pet dogs can be trained to detect eggs with high precision, filling the detection dog shortage with a pack of canine community scientists.

The work “empowers [handlers] to be a part of a grassroots environmental movement,” said study author Dr. Sally Dickinson, a search-and-rescue dog handler and applied animal behaviorist at Virginia Tech, who video-called from a dog-filled van after a training session. “If we can do this and take our dog with us too, we’re in—full send.”

Spotted lanternflies were first detected in the United States in 2014. Likely introduced from Asia through egg-infested landscaping stone, the species encountered few natural predators when it arrived in Pennsylvania and abundant suitable host plants. Hitchhiking on human activities, the insect quickly expanded its range to include at least 18 states, primarily in the eastern part of the U.S. The lanternflies’ voracious appetite for plant sap costs infested regions millions of dollars in economic damage each year.

Removing egg masses is the most effective way to stop the spread, but this is arduous and inefficient for humans. “[Egg masses] often resemble mud smears or lichens and are tucked into bark crevices, cracks, or hidden undersides,” said Dr. Mizuho Nita, a plant pathologist and study co-author at Virginia Tech, in a press release. “Finding them is like searching for a needle in a haystack.”

That’s where dogs’ sensitive noses come in.

The researchers recruited study participants through Facebook posts. Over 1,000 pet owners expressed interest, and 427 had prior odor detection experience. The team whittled the group to 182 dogs based on their geography, with trainees spanning from California to North Carolina. The study participants included a mix of males and females, aged one to 11 years old, with breeds ranging from German shepherds and Labrador retrievers to a miniature poodle and a Boston terrier.

The canine cadets trained on “devitalized” egg masses, which researchers collected from Winchester, Virginia, then froze at −112 degrees Fahrenheit for 30 days to prevent their hatching. The eggs were placed in training packets made of stainless steel mesh, which minimized the risk of spread as they were shipped to study participants.

Handlers worked with their dogs using any protocol they preferred. After three to six months of training, the researchers assessed the dogs’ ability to detect egg masses through three tests.

The first assessment occurred in a controlled indoor environment. Dog-handler teams were presented six boxes in a semicircle, each with a different scent. They were given 90 seconds to distinguish the box with the devitalized egg masses from five distraction odors, which included locally sourced grass, tree bark, and medical gloves. Some trials, unbeknownst to the team, included no egg masses; they succeeded if they gave an all-clear. Each dog completed 10 trials, and they passed the test if they correctly identified the eggs—or lack thereof—in at least eight.

The dogs that passed the indoor test advanced to an outdoor field evaluation, where they searched an open area for three to five concealed egg masses, which were hidden out of plain sight. Teams passed if they correctly identified all or all but one within five minutes, while also falsely detecting no more than once.

Finally, the researchers determined whether the dogs that passed both tests could generalize the odor to detect live spotted lanternfly eggs. Using methods similar to the indoor test, this crucial proof-of-concept evaluated whether dogs could detect real, live eggs after being trained on safer, inert ones.

Of the dogs that attempted each assessment, 74% passed in the indoor trial, 84.8% in the outdoor evaluation, and 91.7% in the live egg test.

Dogs were less able to identify every egg mass in the outdoor field test compared to the controlled indoor trial. Still, they outperformed humans. Even a single egg-mass detection would be impactful in real-world scenarios.

“Spotted lanternfly eggs … they’re hard to find,” said Dr. Jennifer Essler, who studies detection dog biology at the State University of New York College of Agriculture and Technology at Cobleskill and wasn’t involved in the study. “We don’t have a magic wand. We don’t have a metal detector. So anything that dogs can do to improve this finding of the odor is only going to be helpful.”

Essler said people might scoff at the performance decline in the outdoors, “but how well these dogs did is good compared to a human walking into a field, trying to find one inch of brown eggs on hundreds of brown trees.” Indeed, Dickinson’s team just submitted a follow-up study for peer review, in which they found that spotted lanternfly egg searches were more efficient with trained pet dogs than with humans alone.

A wide range of dog breeds excelled in the training program. Dickinson recalled one French bulldog that—wearing clothes and sunglasses—detected a live egg mass during one of its outdoor tests, despite only being trained or tested on devitalized eggs up to that point. “Can any person with any dog train them to detect anything?” she asked. “Absolutely.”

Pet dogs likely can’t undertake intense, multi-day wilderness missions like professional conservation canines, Dickinson said. But with clear guidance, they can play a role in preserving the local environment, such as monitoring shipping areas or surveying farmlands.

The over 1,000 people who expressed interest in participating in the study signal a broad desire to employ pet dogs toward conservation. This new pool of “regular ole doggos,” as Dickinson called them, could expand the supply far beyond what’s available through government agencies and conservation groups. Indeed, there’s a growing interest in scentwork: In 2018, the National Association of Canine Scent Work reported 19,527 members, representing 241 different breeds. That’s the most important takeaway, Essler said—harnessing community science to scale conservation projects.

Still, the researchers acknowledge a need to reduce the high attrition they saw in their experiment. Seventy-eight teams (42.9%) dropped out before attempting the first indoor test. While motive is difficult to determine, the researchers pointed to time demand, dog illness, dog disinterest, and lack of flexibility in test scheduling as potential reasons.

Even with that attrition, however, the study’s sample size far exceeds what’s typical. Previous research on detection dogs for spotted lanternflies, for example, used two, three, or 10 dogs. This study saw 104 teams attempt the indoor trial.

And for the owners and dogs who do persist, the work benefits their relationship as much as it does the environment. Study participants told the researchers that the experience “established a bond and a trust… that can never be broken,” Dickinson said. After the experiment ended, many continued scent training on other odors, while others now work with local zoos and municipalities to eradicate spotted lanternflies.

“Anytime you can stimulate your dog, it’s good for them,” said study participant Bill Wellborn in a press release. Wellborn worked with his seven-year-old Tibetan terrier, Pepe, for 15 to 30 minutes two to three times a week for six months. “Pepe obviously enjoys it. And it’s a way we can take dog skills and training to help our community.”

This story was produced by Atmos and reviewed and distributed by Stacker.