Pestology Blog
Argentine Ants, House Mice, and Asian Tiger Mosquitoes
Fairfax, VA – October 1, 2026
In this month's episode, the team covers new research on baiting options for Argentine ants, management solutions for house mice, and new range distribution information for the Asian tiger mosquito. We're joined by special guest, Olivier Roy of Maheu Protection Parasitaire in Quebec, Canada.
Featured Article Summaries
Argentine ant
Behavioral Effects of Low Concentrations of Boric Acid and Thiamethoxam Baits on Laboratory Colonies of the Argentine Ant
Ants are frequently rated as one of the most difficult pests to manage by pest management professionals. This is often thanks to both their biology and resilience. But arguably one of the major factors that makes ants so tricky to manage is their behavior. Yet, most studies concerning management of ants simply focus on if product going to be sufficient to kill the ants. But as many pest management professionals know, the story is not always that simple.
This study decided to examine the behavior of how ants react to low doses of two common ant bait ingredients- thiamethoxam and boric acid. And they decided to examine this in one of the most notorious invasive species in both urban and agricultural environments- the Argentine ant.
The researchers set up thirty colonies and assigned them to a treatment that was served in a 25% sucrose solution: a low-dose of boric acid, a low-dose of thiamethoxam, or the sucrose solution alone, which acted as the control. The researchers took measurements of the location of the ants over the next three days post application of the bait. The researchers found that ants treated with boric acid featured a higher density of ants staying near the nest, while the ants treated with thiamethoxam were more likely to be outside of the nest area. In terms of numbers, ants treated with thiamethoxam increased their activity outside the nest by 862.3%, meaning that the majority of the colonies were out and about following consumption of that product.
The researchers additionally performed measurements on individual ants. Measurements of individual ants included total distance traveled, and also included time spent in light and dark areas in the measurement arena. There was no difference in the amount of distance traveled between treatments, but ants that had been treated with thiamethoxam spent more of their time in the light compared to the control and boric acid treated ants.
The researchers point out that these differences are likely due to the way both chemicals work. Boric acid affects the guts and the excretion systems of insects. Therefore, with the toxic effect on their guts, the colony may be less willing to forage and therefore stay closer to the nest. Boric acid has also been known to disrupt water regulation in Florida carpenter ants, so Argentine ants could also be trying to conserve moisture as best they can by aggregating in the nest.
Thiamethoxam, however, is a neurotoxin that affects the nervous system of insects by causing overstimulation of certain receptors that eventually leads to paralysis. In the case of the Argentine ants, it appears that low doses of this neurotoxin result in elevated activity outside of the nest and reduced nest cohesion. In addition, it also appears that thiamethoxam may disrupt light-avoidance behavior as well.
Not only does this study assist with how we should approach making bait formulations for ant management, but it also provides clues as to how these common ant bait ingredients affect the colonies behaviorally. This is especially pertinent in ants, as they will share the bait with the rest of the colony through trophallaxis, or more affectionately, sharing their food. This means that not every ant will receive the same dose of the product in the ant bait. This could provide some explanation for why some ant colonies appear to become more active post-baiting, and more importantly, allows pest management professionals to provide more context for your client as to why they may see a spike in activity post-treatment.
Article by Laura Rosenwald, MS, BCE
References
House Mice
Eco-friendly Strategies for Controlling House Mice and Overcoming Trap-shyness
The house mouse is a prolific pest that most folks probably don’t even realize is invasive. They are found across the world in a wide variety of habitats and are pests of human structures. These rodents contaminate food commodities, spread diseases, and destroy property, meaning PMPs are tasked with managing them.
Managing a mouse infestation is a difficult task in part because of the intelligence and social behavior of mice. Mice often will avoid traps. The researchers wanted to test what could be done about this in this experiment asking whether a simple environmental change like disguising the traps could make mice keener on accessing them.
Mice can be neophobic, meaning afraid of new things. This may cause them to avoid traps or bait stations simply because it is a newly introduced item in their environment. Traps can be a tough sell for mice who aren’t too sure about new items. On the flip side, mice can also learn when things are dangerous, so if one mouse gets caught in a trap, they may learn to avoid it. Basically, the mice are pretty darn smart.
In this experiment, they selected three large chain stores which had reported house mouse issues. These were stores that sold a variety of items including groceries and daily essentials. They got a baseline for the mouse population by using a formula that used food consumption over time based on how much food mice usually eat. For context, store 1 had 300 mice to start, store 2 had 230, and store 3 had 260. So there was a LOT of mice.
There was a dry bait which was peanuts, and there was a wet bait which was cucumbers. They had 4 phases of the experiment with the traps. The traps were Faragir live traps which are plastic bait boxes. Anyways, the first phase was pre control which was before anything was put out, pre trap shyness, which was the first phase when traps were initially introduced and shyness wouldn’t have happened yet; post trap shyness, which was after the mice have become familiar with the traps and shyness has begun; and finally post camouflage trap which was when the camouflaged traps, covered in mud were introduced to avert the trap shyness.
For each phase of the experiment, the amount of bait taken was measured daily. The food consumption followed as expected for the initial phases with most food being consumed
in that pre control phase, slightly less consumed during the pre trap shyness phase because of course the bait box made it harder to get to the food compared to it just being available. After trap shyness set in, food consumption dropped dramatically by about half.
The number of mice caught was evidence of this shyness as well. With initial pre shyness, they caught about half the total population then when shyness set in, they caught only about 10% of remaining mice. Then everything changed with camouflage. The food consumption when down a bit, as we know there are less mice now. But the traps caught 8-10 times the mice from the shyness phase. To summarize, new traps caught about half the mice. After the mice learned the traps were scary, only about 10% of the remaining got caught, then with camouflage, the catch increased dramatically, catching most of the rest of the mice.
Recall they were also looking at bait type, and they saw that the peanuts yielded more consistent numbers compared to the cucumber. This is not to say that every mouse prefers peanuts over cucumber, but it highlights that the type of bait itself can be critical in the effectiveness of baiting.
By the end of the experiment, the food consumption was greatly decreased which proves that the trapping reduces rodent damage, and the camouflage on the traps made the mice much more comfortable with them and trapping was very successful compared to the shyness.
In the context of this paper, the authors highlight this as an example of a chemical free option since it was a live catch bait only trap but i think that one could take this a few steps further and eventually do a study on rodenticide baited traps with camouflage too.
Ellie Sanders, BCE
ECO-FRIENDLY STRATEGIES FOR CONTROLLING HOUSE MICE AND OVERCOMING TRAP-SHYNESS
Authors: Samira Hajialiloo bonab, Gholamhossein Moravvej, Roohollah Siahsarvie
Journal: Journal of Animal and Plant Sciences (JAPS)
ISSN: 1018-7081 (Print), 2309-8694 (Online)
Volume: 36 Issue: 2 Pages: 341-347
Year: 2026
DOI: https://doi.org/10.36899/JAPS.2026.2.0029
URL: https://doi.org/https://doi.org/10.36899/JAPS.2026.2.0029
Publisher: Pakistan Agricultural Scientists Forum
Asian Tiger Mosquitoes
Continued Range Expansion of Aedes albopictus (Diptera: Culicidae) in Iowa, United States
The Asian tiger mosquito, Aedes albopictus, is a highly invasive mosquito species that first showing up in the US back in 1985. Since then, this mosquito has successfully hitchhiked its way to every continent on the planet except Antarctica. It became a household name back around 2016 during the Zika virus outbreak, but it’s also a competent vector of several other globally threatening diseases including dengue and chikungunya.
Monitoring the range expansion of Ae. albopictus across North America has played an important role in our vector surveillance and control efforts. The main limiter for the norther range expansion of this species in the US has been temperature, and for years the going assumption was that Iowa's cold climate would be the dividing line. But a new update from Iowa State University suggests otherwise.
Aedes albopictus wasn’t really on Iowa’s surveillance radar until the Zika outbreak prompted more states to launch a targeted invasive Aedes surveillance initiative nationwide. That effort turned up established populations in 3 Iowa counties between 2016 and 2020. This most recent study picked up where that left off, covering 5 more years of trapping (2021 to 2025) across 19 counties, using a mix of G-Sentinel traps, Gravid Aedes traps (GATs), and equipment originally deployed for West Nile virus surveillance.
Their results showed the Asian tiger mosquito’s foothold in Iowa had more than tripled since the 2020 dataset was published. Aedes albopictus was detected in 11 counties, with established populations likely present in 10 of them. That's up from the original 3 counties identified in 2017. The one outlier, Woodbury County, was written off as a probable one-time introduction since researchers only turned up a single mosquito across multiple years of trapping.
Of the 11 Iowa counties identified in this paper, it’s thought that Polk County likely served as an introduction point for the Asian tiger mosquito. Polk County (home to Des Moines) has had a known population since 2017, with all early detections clustered within a 3-mile radius of a tire recycling facility. It’s thought that this served as an important introduction point for the species in Iowa given the affinity Aedes albopictus have for used tires as a preferred oviposition (or egg laying) site, and the role that used tires have played in ferrying Aedes albopictus and Aedes aegypti eggs around the globe. By 2025, positive sites in Polk County had doubled from 4 to 8, including detections more than 15 miles from that original hotspot.
The authors also give a shout out to citizen science for catching populations that a limited surveillance program could otherwise miss. In 2022, two separate Scott County residents reported unusual mosquito activity around their homes; when the state supplied them with Gravid Aedes traps to investigate, the follow-up trapping confirmed the county's population, something years of official surveillance through 2020 had failed to pick up.
The continued expansion of this species and other arthropod disease vectors across all of North America is something that should have everyone’s attention. While the incident rate of mosquito borne disease in the US isn’t as high as many other countries around the world, we’re not immune. Locally acquired dengue transmission cases in Florida, California, and Texas have become an annual occurrence over the last 5 years. And new states are being added to the list, with Virginia recording the first ever documented case of locally acquired dengue just this August.
So where does the professional pest management industry fit in with all this? PMPs are working in neighborhoods and commercial outdoor spaces every day, completing services in the preferred habitat for Ae. albopictus every day. Our industry is uniquely positioned as a front line of defense against these backyard breeding mosquitoes through our professional backyard management programs. Additionally, service professionals can serve as an early warning system for new introductions, much like professionally trained citizen scientists, delivering important early surveillance data when new or unknown mosquitoes are encountered in the field.
Article by Mike Bentley, PhD, BCE
References
Christopher H Lee, David R Hall, Ryan C Smith, Continued range expansion of Aedes albopictus (Diptera: Culicidae) in Iowa, United States, Journal of Medical Entomology, Volume 63, Issue 2, April 2026, tjag052, https://doi.org/10.1093/jme/tjag052
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