Adam Carace of Pest-End Exterminators, which services accounts in Massachusetts, New Hampshire and southern Maine, shares the story of an elderly couple who lived in a house that the wife had made home to an enormous population of rat “pets.” She fed and cared for dozens of them, and stored 50 or so rat corpses in Tupperware containers on the back porch. Carace’s only choice for ridding the house of rats was calling the health department for support. The couple had no sense of the health dangers associated with living with rodents.

David Marshall of Arizona Pest Squad tells a similar story: He called the health department when a customer whose home was crawling with rats refused to acknowledge the dangers of allowing these rodents to live and breed there.

“He had a serious infestation in his attic, and live rats stuck to glueboards throughout the house,” Marshall explains. “I explained to him the health dangers to his children and himself, as well as their neighbors. He didn’t take it seriously until a representative from the health department showed up. It took a court order to get the place cleaned up.”

Unfortunately, these stories (Tupperware aside) aren’t that unusual. Many people simply don’t understand the health implications of rats and other rodents. Only 28 percent of the PMPs PCT surveyed for last year’s State of the Rodent Market report, sponsored by Bell Laboratories, believe that the public understands that rodents can carry human disease, only 18 percent say that people recognize that rodent hairs and feces can contaminate food, and a mere 12 percent report that the public views rodents as a source of allergens and asthma triggers.

Educating customers is always a responsibility for PMPs. In the case of rodents, communicating the dangers is paramount to public health and safety.

Despite their considerable impacts on human health, the food supply and physical/structural damage, urban rats are under studied. In fact, most of the published literature on rats dates back to the mid-1900s. In recent years, however, rodent researchers across the globe are starting to take a closer look at these pests that thrive in human environments. In November 2017, five articles were published that examine the biology, ecology and evolution of rats. Here are some takeaways:

Genomics Shift in Urban Environments

An article published in Science by Marc Johnson and Jason Munshi-South highlights the role that urban environments play in the evolution of wildlife, and how an understanding of evolution can help mitigate pest problems. For example, cities can isolate populations by creating barriers to movement such as busy streets that are dangerous to cross. As a result, rats and other urban wildlife can be clustered into groups of closely related organisms. By understanding gene flow in these populations, we can learn about the actual area that a cluster of rats occupies, whether it’s a single building or a whole city block. This information is important for management since eliminating rats from one food establishment may have little impact on the population that can quickly re-infest the site from nearby areas.

NYC Rats Arrived in the 1700s — Then Closed the Doors

Having taken samples of rats across the entire island of Manhattan, Matt Combs and others found that all NYC rats share an evolutionary relationship with rats from Great Britain and France. This makes sense based on the trading history between the colonies and Europe in the 1700s. What’s surprising is the lack of genetic evidence for rat introductions from any other part of the globe. This suggests that New York City rats have repelled or killed all rats that arrived at the port of New York since the 1700s! In ecology, this is known as biotic resistance, where an existing group of organisms is able to repel invading ones.

Rat Populations are Patchy in Urban Areas

Several studies show that rats are not found throughout urban areas, but are instead found in “hot spots.” This is likely due to the availability of environmental conditions that favor rats, such as the presence of food, water and shelter. Research by Laura Angley and others showed nearby rat colonies could be genetically different, while rats further apart in comparable habitats showed some similarity. Is it possible that rat genomics lead to habitat preferences? That some rats prefer to live in housing, some in parks and others in commercial buildings?

Another finding in NYC was that rat populations greater than 0.87 miles (1400m) apart were genetically distinct. Based on the data, it seems that a small number of rats may move between these populations occasionally, but not enough to keep them genetically related. Most interesting and comical, uptown rat populations have limited breeding contact with downtown populations. While the Internet has enjoyed plenty of “Uptown Girl” parodies based on this result, the best explanation for this finding is that the midtown area serves as a buffer against rat movement. This could be due to differences in suitable habitat, pest management efforts or the availability of food resources.

Rodent-Borne Disease is Patchy in Urban Areas

Just as rat populations are patchy in urban environments, rodent-borne disease is also found in hot spots. Amy Peterson and others showed that rats in New York City and New Orleans are host to multiple species of Bartonella; a group of bacterial pathogens that cause fever and associated symptoms in people. But the occurrence of Bartonella in rats depended on the exact site where they were collected, and in New Orleans on the species of rat that was collected. (New Orleans is home to both Norway rats and roof rats.) Similarly, the paper by Angley and others found an uneven distribution of rodent pathogens in New York. These researchers noted some populations had a very high percentage of infected rats, and that rats from those sites were host to a greater diversity of pathogens and ectoparasites. Importantly, both studies state that the patchy occurrence of rodents and disease means that human health risks are unknown and can only be determined with more thorough sampling.

Rats are Really Difficult to Study

As someone who has conducted rodent research, I can tell you rats are hard to study. They are secretive, live in areas where access is difficult, nest underground, are nocturnal and are likely to be killed before we can study them. Unlike wildlife in other settings, urban rats are not easily tracked with radio telemetry or Global Positioning System (GPS) because of interference from buildings and hard surfaces. In a recent study by Kaylee Byers and others from The Vancouver Rat Project (www.vancouverratproject.com), they rediscovered this difficulty in trying to track movement of rats. The researchers “chipped” 14 rats with GPS tags that could either remote-download or store movement data. Unfortunately, the researchers were not able to obtain data from the devices, and when they recaptured three of the rats, the tags had been removed. The researchers said, “The ecology of Norway rats interferes with the effective use of GPS tags in urban settings.”

MORE QUESTIONS THAN ANSWERS.

Urban rodents have plagued cities around the world throughout recorded history, and efforts to eliminate them come in waves. In some cases this is based on financial resources, or the result of political campaigns, as described in Robert Sullivan’s book, “Rats.” The recent use of genomics to understand migration patterns of rats across the globe and at smaller spatial scales gives us new insight into their complex and secretive lives. Yet we are faced with more questions than answers about the risks they pose to human health and how best to manage rodents at large spatial scales.

Matt Frye is community IPM extension educator at Cornell University New York State IPM Program, and can be contacted at mfrye@gie.net.

When hearing the words “Deader Than Dead Tour,” a person might conjure images of a strange sort of Grateful Dead revival or perhaps a tour of a new death metal band. But, when seeing the actual Sentricon System Deader Than Dead Tour main act — the Coroner’s Caddy, a 17-foot hearse with a 100-pound replica of a deceased termite on the rooftop — feelings of curiosity and intrigue surely would be summoned by people in the area.

WHAT IN THE WORLD? The Sentricon system team had the idea to create a giant termite model, attach it to the roof of a hearse, and then tour six cities across 12 states in 26 days during peak termite swarm season in March and April. There were a few goals for this clever termite awareness tour, in addition to kicking off during the National Pest Management Association’s termite awareness week (March 11-17).

Brooklynne Dalton, urban pest marketing communications manager, Corteva Agriscience, said the tour helped support Certified Sentricon Specialists — companies that are qualified to install and service the Sentricon system — with their marketing and education efforts to homeowners on the importance of preventive termite control and the value that the Sentricon system provides by eliminating the entire colony, including the queen. While on the road, the tour participants focused on “gathering and sharing success stories [from pest management professionals and homeowners], encouraging proactive treatment and elevating the threat that termites pose,” says Dalton.

TAKING OFF. Plenty of planning and preparation were involved to make a success out of this unique, educational road show. The Sentricon system marketing team worked closely with Sentricon territory managers to plan and map out the tour. A few Certified Sentricon Specialists were a bit skeptical at first, but the “overwhelming majority were supportive of the idea. You have to break through the clutter in today’s market and make people do a double-take,” explains Dalton. And, speaking of double-takes, she says that since every good tour has a tour bus, or a symbol of the tour, the hearse with a 7-foot dead termite on top really captured the message of this expedition.

Dubbed the Coroner’s Caddy, the 17-foot hearse was purchased, and the 100-pound, 7-foot termite replica was fabricated by a Milwaukee-area company in a five-week process using foam, wires, epoxy and then paint to reflect a real-life but giant termite. The Coroner’s Caddy drew “quite a few looks as we were driving across the 12 states,” Dalton says. As a result, the tour gained great momentum. The hearse was eye-catching and started conversations about termite awareness and the threat that termites pose. Plus, the vehicle’s visual component helped to, Dalton says, “pique the interest of people not directly involved in the pest control industry.”

TOUR STOP RESULTS. In addition to raising awareness about the threat that termites pose, at each tour stop, Certified Sentricon Specialists were given the opportunity to interact with customers and the community. The Coroner’s Caddy made six official stops on the following dates at these locations:

• 3/16/18: Cayce, S.C., at Home Pest Control
• 3/20/18: Metairie, La., at Terminix Service Company
• 3/22/18: Mobile, Ala., at Arrow Exterminators
• 3/29/18: Lubbock, Texas, at D’s Pest Control
• 4/04/18: Manhattan, Kansas, at American Pest Management
• 4/10/18: Cincinnati, Ohio, at Scherzinger Pest Control

At the fifth stop in Manhattan, Kansas, Travis Aggson, executive vice president/Associate Certified Entomologist, American Pest Management, found the timing of the tour and the excitement and hype for termite awareness week to be beneficial to the Deader Than Dead Tour stop at his company. “Every year we try and bring awareness of termites during the swarm season to the communities we serve,” using radio ads, social media and public outreach events, he says. But, this year the tour using a 17-foot hearse with a giant termite attached created a huge buzz.

American Pest Management hosted an entire day dedicated to the event. The company visited a local elementary school for a “good bug versus bad bug” presentation. And, there was a barbecue for more than 100 guests, counting the city’s mayor, and with invitations to members of the local Builders Association, Realtor Association and Chamber of Commerce. The regional television station featured a story on the news as well.

“Our main objective was to create awareness, [and] we feel this event started our heavy pest pressure season off with a bang,” Aggson says.

At the sixth and final stop of the tour, Eric Scherzinger, vice president of sales and marketing, Scherzinger Pest Control, admits that there were some initial hesitations about participating in the Deader Than Dead Tour due to how a “big termite on top of a hearse” might be perceived. But, the reservations were countered with marketing awareness, people taking pictures with the Coroner’s Caddy (“not something you see every day,” says Scherzinger) and the entire event generated lots of conversations. All of the news agencies in Cincinnati had been contacted and visited, and given themed cookies decorated with the Deader Than Dead Tour logo.

The hearse also drove to a special reception for the National Apartment Association to generate additional termite protection awareness. Scherzinger said the tour “was definitely worth it. It ended up being really neat.”

Editor’s Note: The following article appeared in Mike Merchant’s blog, “Insects in the City,” which can be found at insectsinthecity.blogspot.com. The blog offers readers news and commentary about the urban pest management industry and is excerpted here with permission of the author.

After identifying an unusual insect for a homeowner recently, the thank you email ended with a bang. Because I was able to quickly identify her pest, which her PMP had incorrectly insisted was a “bee,” she concluded, “[I guess] it’s best I change pest control companies.”

Ouch...I hate to hear that.

Admittedly the insect was an obscure critter. I’m guessing that not one in 100 pest management professionals has ever heard of a chalcid (CHAL-sid) wasp before. But chalcid wasps are common natural enemies of many insect pests. Identified by their small size and giant hind femurs, the Chalcididae family makes up one of the dozen or so “parasitoid” wasp families within the bee/wasp/ant order Hymenoptera.

A FASCINATING INSECT. Parasitoid wasps are certainly one of the most fascinating and wonderful, yet horrifying, of all creatures. So seemingly cruel in its behavior, theologians and biologists argued over the last 200 years whether the mere existence of insects like the ichneumon wasp (a cousin of the chalcid wasp) served as proof against the Christian belief in a loving Creator-God.*

Photo courtesy Texas A&M AgriLife Extension

Parasitoids are parasite-like predators. Like a parasite, they grow up feeding on or in a single host. But unlike true parasites, which weaken but rarely kill, parasitoids invariably kill their hosts. Parasitoids begin their lives as an egg laid by their mother on a soft part of a host’s anatomy. Upon hatching the parasitoid larva burrows into the body cavity of its host and begins feeding. The larva knows instinctively to begin with the non-essential parts, prolonging the life of its victim as long as possible. Eaten alive from the inside, ultimately the host dies. Ugh.

It does sound cruel, but parasitoids are also one of nature’s most effective population control agents. Without them, crops would vanish under billions of caterpillars. Flies would breed unchecked. Even spiders would be more abundant than they already are. Parasitoid wasps possess some of the world’s sharpest “noses” (actually antennae), able to sniff out prey even when the prey are vanishingly rare. They are also smart, with some species recently being trained to sniff out illicit drugs and even bombs on the battlefield. Gardeners and farmers especially reap the benefits of parasitoid services every day.

Admittedly, we in structural pest control don’t have many chances to encounter parasitic insects in our daily work. Most parasitoid wasps live peacefully out of sight in the natural world, ill at ease in our indoor environments. Occasionally, though, parasitoid wasps make an appearance in a home or business. For this reason, it’s a good idea for PMPs to know something about these insects.

The species of chalcid wasp my homeowner encountered “swarming” in her attic this spring appeared identical to other similar wasp pictures I’ve received recently. These turned out to be Brachymeria podagrica, a parasitoid (primarily) of flies. Their presence indoors suggests that the source could have been a dead animal full of fly larvae somewhere in the home — a theory backed up in this case by the homeowner’s report of a foul stench several days before the little wasps appeared in the attic. Likely they were drawn to the smell of the carcass in search of their blow fly hosts.

ACCIDENTAL INVADERS. When one, or a few, unusual insects show up overnight in a structure, they are often called “accidental invaders.” Accidental invaders are chance occurrences, when an insect or spider accidentally enters through an open door or window, or unsealed crack. Such accidental entries occur on a regular basis in residential accounts but usually with a variety of arthropods. But when several (or dozens) of the same kind of insect appear inside a home, or when the same insects show up over many days, it usually means something is afoot. Insects always have a story to tell, and they never lie.

Chalcid wasps are not likely to enter an account over and over by accident. If you find chalcids indoors, get a sample and have them identified. Brachymeria podagrica suggests the possibility of wildlife or rodents; however, other species of Brachymeria and other species of chalcids are known to parasitize beetle or moth larvae and might be evidence of a stored product pest infestation.

And remember, if you’re ever unsure of the identification of an insect, don’t hesitate to bring it to your in-house entomologist (if you have one), or send it to your state university or other reputable insect ID authority. And don’t just call something strange a “bee” unless you know for sure that it is.

*An interesting discussion of the ichneumon wasp controversy can be found in Stephen Jay Gould’s essay on “Non-moral Nature” in the book “Hen’s Teeth and Horse’s Toes.” 

The author is an entomology specialist for Texas AgriLife Extension.