Can Pet Dogs Find an Invasive Species? Citizen Scientists Reveal Promising Results

A groundbreaking citizen science initiative has demonstrated that pet dogs possess a remarkable ability to detect the egg masses of the invasive spotted lanternfly (SLF), offering a potential new tool in the fight against this destructive pest. The multi-university study, involving Texas Tech and Virginia Tech, leveraged the keen olfactory senses of everyday canines, with dog trainer and author Melissa McCue-McGrath leading a cohort of participants whose dogs, many with existing behavioral plans, successfully navigated the challenges of scent detection. This pioneering project not only validates the efficacy of canine detection in ecological conservation but also underscores the dedication of citizen scientists in addressing pressing environmental threats.

The Invasive Threat: Spotted Lanternfly’s Destructive Path

The spotted lanternfly ( Lycorma delicatula ), an invasive planthopper native to Asia, first appeared in the United States in Pennsylvania in 2014, believed to have arrived on shipping crates. Since its initial detection, it has spread rapidly across numerous states, posing a severe threat to agriculture, forestry, and native ecosystems. The insect primarily targets the Tree of Heaven (Ailanthus altissima), itself an invasive species, but its diet extends to a wide array of economically vital plants, including grapevines, hops, maple trees, apple trees, and various stone fruit trees like cherries and peaches.

The damage inflicted by the SLF is multifaceted. Adult lanternflies feed by piercing the bark of trees and vines, siphoning off sap. This feeding activity, particularly when populations are high, weakens the host plants, making them more susceptible to disease and other environmental stressors. A more insidious consequence is the production of "honeydew," a sticky, sugary excretion left behind by the feeding insects. This honeydew coats plants and structures, attracting other pests like wasps and ants, and, critically, promoting the growth of black sooty mold. This mold, while not directly harmful to the plant, covers leaves, obstructing photosynthesis and reducing crop yields, ultimately leading to plant decline and even death. For industries reliant on these crops, such as viticulture, maple syrup production, and fruit orchards, the economic implications are dire. In Maine, where Melissa McCue-McGrath resides, the SLF is predicted to arrive by 2026, posing an imminent threat to the state’s significant maple and blueberry industries, among others. Its current presence in neighboring New Hampshire, just 20 minutes from southern Maine, highlights the urgency of developing effective detection and mitigation strategies.

A significant challenge in controlling the SLF lies in detecting its egg masses. These masses, typically laid in late fall and overwintering until hatching in late March or early April, are incredibly cryptic. An "opportunistic layer," the female lanternfly will deposit her eggs on almost any flat surface – trees, rocks, outdoor furniture, vehicles, and even homes. The eggs are then covered with a protective, mud-like substance that effectively camouflages them, making visual detection by humans exceedingly difficult. This characteristic allows the eggs to be inadvertently transported long distances on cars, trains, and shipping containers, facilitating the rapid spread of the invasive species to new territories.

Citizen Science to the Rescue: A Proof-of-Concept Study

Recognizing the limitations of human visual detection, researchers from Texas Tech and Virginia Tech launched a novel "proof of concept" study to explore whether pet dogs could be trained to locate SLF egg masses. The project sought to harness the extraordinary olfactory capabilities of canines, which have long been utilized in fields ranging from search and rescue to drug and bomb detection. The initiative embraced a citizen science model, inviting dog owners and their pets to participate in data collection, thereby expanding the geographical reach and practical application of the research.

Among the participants was Melissa McCue-McGrath, a professional dog trainer and behavior consultant with extensive experience using scent work as a behavioral tool to build confidence and skills in dogs, particularly those with complex behavioral histories. McCue-McGrath’s involvement was serendipitous, spurred by a student who had heard about the multi-university study. Having previously explored the intersection of animals and humanity through her podcast, Bewilder Beasts – featuring stories of bees trained to detect bombs and honeybees inadvertently collecting honeydew from SLF – McCue-McGrath was immediately intrigued. She recognized the potential, stating, "If we can train bees to find a bomb in Croatia, I can train these five dogs or six dogs to find this egg mass."

Unlike many scent detection programs that recruit highly competitive sport dogs, McCue-McGrath’s cohort was distinct. Her team comprised six dogs, five of whom had ongoing behavioral plans, ranging from separation anxiety to reactivity. This presented a unique challenge and opportunity for the study: could everyday pet dogs, even those with behavioral quirks, be effectively trained for this specialized task? The scientists, initially seeking handlers with National Association of Scent Work (NASW) certifications, ultimately accepted McCue-McGrath’s diverse team, a decision that would yield compelling insights into the adaptability of canine scent detection.

Training Methodology and Overcoming Logistical Hurdles

The training regimen for the dogs was rooted in associative learning, a fundamental principle of operant conditioning. This method involves pairing the target odor (SLF egg masses) with a highly valued reward, typically food. Over repeated trials, the dog learns to associate the specific scent with the positive reinforcement, developing a strong motivation to locate it. McCue-McGrath’s existing scent work classes, which often utilized clove oil or birch oil on Q-tips, provided a solid foundation. Most of her dogs, having engaged in scent work for several years, already understood the "game" of finding a designated odor. Introducing the SLF egg masses essentially added another scent to their "scent Rolodex," a process they quickly adapted to. The dogs showed a particular affinity for the SLF odor, described as "decaying matter," often prioritizing it over other scents in subsequent tests.

The project, initiated in late 2023, was not without its logistical and environmental challenges. Following the initial submission of participant profiles between April and May 2023, McCue-McGrath’s cohort was selected in November 2023 for a second phase of funding. The distribution of the crucial training material – dead, flash-frozen SLF egg masses enclosed in window screen mesh – became an adventure itself. McCue-McGrath, dubbed the "dead fly fairy," had to deliver these specimens to her students amidst a severe blizzard in Maine in January. This led to an unexpected encounter with a school resource officer while delivering eggs to a student working at an elementary school. The sight of a non-parent handing out suspicious-looking metal mesh squares led to a brief, albeit humorous, interrogation, highlighting the unusual nature of the scientific endeavor.

Due to the extreme weather, the initial training class had to be conducted via Zoom. This technological necessity meant McCue-McGrath herself couldn’t directly train her own dog, Captain, for the first session. Instead, her 11-year-old daughter stepped in, successfully getting Captain "on odor" within four trials. This rapid acquisition of the target scent by all participating dogs, despite the challenging circumstances and their diverse backgrounds, underscored the innate capabilities of canines and the effectiveness of the associative learning method.

Field Trials and Remarkable Canine Performance

The study involved a structured progression of tests, culminating in field trials designed to simulate real-world conditions. The first hurdle was the Odor Recognition Test (ORT), which dogs had to pass within 14 weeks of receiving the eggs. The ORT consisted of six boxes, one containing the SLF egg mass in mesh, another containing only the mesh (to rule out detection of the material itself), and others with distractors like grass or mulch. Dogs were required to correctly identify the SLF egg mass in 80% of 10 trials to advance. Four of McCue-McGrath’s dogs successfully met this criterion.

Following the ORT, the qualified dogs proceeded to the field trials. McCue-McGrath thoughtfully designed two 25-meter by 25-meter (approximately 80 feet by 80 feet) courses on her property: one in a wooded area and another in an open field. This dual setup accommodated the behavioral preferences of her dogs; one dog, having had a negative experience, avoided the woods, while another was easily distracted by chipmunks in open areas. Within 16 to 18 weeks of commencing training, all four dogs successfully completed their field trials, demonstrating their ability to locate the hidden egg masses in varied outdoor environments.

A particularly compelling observation came from dogs participating in the study in areas of live SLF invasion, such as Ohio. During their field tests, which were set up with dead fly eggs, some dogs began alerting in unexpected locations. Upon investigation by evaluators, it was confirmed that these dogs were, in fact, detecting live SLF eggs, demonstrating an easy transition from the training odor to naturally occurring targets. Even McCue-McGrath’s own dog, Captain, who had been pulled from the formal study early due to a medical issue and never completed the ORT, successfully cleared both courses in the field trial, identifying the odor with no problem. This highlighted the dogs’ inherent ability to generalize the scent and the robustness of their training.

The Human Element: Advocacy, Resilience, and Attrition

Beyond the scientific data, the study offered profound insights into the human-animal bond and the challenges inherent in citizen science. One poignant story involved June, a dog with significant anxiety. During an ORT attempt, an unexpected blaring fire truck caused June to freeze and lose composure. Her owner, prioritizing June’s well-being, made the difficult but ethical decision to withdraw her from the formal testing, stating, "This is supposed to be fun for her. It’s not. I can’t in good conscience keep going with this." McCue-McGrath supported this decision, acknowledging it as "the right decision" for the dog’s behavioral health. Instead of SLF eggs, June was given a "cheese in the box" test, which she enthusiastically aced, visibly relaxing and regaining her confidence. This act of handler advocacy not only protected June but also provided a valuable lesson in balancing scientific objectives with animal welfare. Months later, June returned to scent work, becoming McCue-McGrath’s most reliable lanternfly hunter, even using the scent to overcome fear during an agility class. Her story exemplifies the therapeutic power of scent work for behavior-challenged dogs and the critical role of understanding and adapting to individual animal needs.

The human element extended to the entire cohort. McCue-McGrath noted the significant personal challenges faced by her group during the study, from her own daughter’s severe anxiety to a handler coping with a parent’s Alzheimer’s. This shared vulnerability fostered a strong sense of camaraderie and mutual support, demonstrating how citizen science projects can build community and resilience among participants.

The study also revealed a significant 40% attrition rate among the initial 180 citizen scientist participants. While the specific reasons for withdrawal are not fully understood, McCue-McGrath speculated about factors such as severe weather, the demands of the training protocol, or perhaps a mismatch between initial enthusiasm and the realities of scientific rigor. This attrition rate, while seemingly high, is not uncommon in large-scale citizen science projects and prompts further inquiry into participant motivation and retention strategies. For the Maine cohort, a sense of "sheer spite" and commitment to seeing the project through, even amidst personal hardship, proved a powerful motivator.

Implications for Conservation and Future Directions

The success of this proof-of-concept study has significant implications for conservation efforts and the future of citizen science. It demonstrates that ordinary pet dogs, with appropriate training, can become valuable assets in detecting invasive species, particularly those that are difficult for humans to locate. However, McCue-McGrath strongly cautions against independent, untrained attempts to replicate this work. The selection of target invasives is paramount; for instance, training dogs to detect the brown-tailed moth, whose toxic hairs can cause severe rashes and respiratory issues, would be irresponsible and harmful to the animal. Collaboration with environmental experts, such as extension schools or regional environmental agencies, is crucial to identify safe and appropriate targets, understand life cycles, and ensure that citizen science efforts do not inadvertently exacerbate ecological problems.

The focus on SLF eggs rather than live insects was a deliberate decision, informed by environmental and plant scientists. Targeting the overwintering egg masses offers the most effective point of intervention to reduce the next generation of lanternflies. This strategic thinking is essential for any future canine conservation project. Potential next steps in canine-assisted invasive species detection in Maine could include the emerald ash borer, which exclusively targets ash trees and is already present in the region.

This project is part of a broader movement in "conservation canines" or "invasive species detection dogs," where animals are trained to locate endangered species for monitoring or invasive species for eradication. While such operational work typically involves hundreds of hours of training and is often volunteer-based, the SLF study illustrates how even short-term, focused citizen science projects can yield meaningful results. The adaptability of dogs, even those with behavioral challenges, to this type of work opens doors for a wider range of participants to contribute to scientific discovery and environmental protection.

Broader Insights from the Dog Training World

Melissa McCue-McGrath’s work on the spotted lanternfly project is just one facet of her dedication to the dog training profession. Her latest book, Misadventures of the World’s Okayest Dog Trainer, delves into the often-unseen realities of the industry. Inspired by her experiences as a faculty advisor for the Victoria Stilwell Academy, where she mentored new trainers, the book aims to fill the gap between theoretical knowledge and practical, sometimes messy, application.

The book is a collection of personal stories that highlight broader issues within dog training, from humorous misadventures to heartbreaking cases. It explores topics such as the prevalence of sexism in a female-dominated industry (McCue-McGrath’s research indicates that approximately 89.9% of dog training graduates are women or non-binary individuals, yet misogynistic attitudes persist). It also delves into the unexpected challenges trainers face, such as walking into a seemingly simple "jumping case" that quickly escalates to a bite history or discovering a hoarding situation. Much like the narratives of veterinarians Dr. Philip Schott and Dr. Nick Trout, McCue-McGrath’s book offers a behind-the-scenes look at the emotional, intellectual, and often unpredictable journey of a professional dog trainer, providing valuable context for both aspiring professionals and curious dog guardians.

The spotted lanternfly detection study stands as a testament to the power of citizen science and the untapped potential of our canine companions. By effectively leveraging the natural abilities of pet dogs, this proof-of-concept research offers a promising, environmentally friendly avenue for invasive species management, while simultaneously fostering community engagement and a deeper appreciation for the complex world of animal behavior.