Pestology Blog
BugBytes LIVE Episode at Pestworld 2025 Orlando
Fairfax, VA – November 1, 2025
BugBytes recorded our third LIVE episode at PestWorld 2025! In this live episode, the team covered new research on mosquito host-seeking behavior, the latest advances in termite baiting, and novel stored product pest management techniques! We're joined by a live audience as our guest judges this episode!
Featured Article Summaries
Mosquito Threat Avoidance
Visual Threat Avoidance While Host Seeking by Aedes aegypti Mosquitoes
Your mission, should you choose to accept it, is simple: Obtain blood from a host organism so that you will have the protein available to make eggs. This message will self destruct in five seconds.
Okay, so maybe mosquito females don’t get a tiny little tape-recorded message prior to seeking out a host, but it is still quite a dangerous mission for them to undertake. Hosts have several means of evading mosquitoes, with swatting arguably coming up at number one. So, how do mosquitoes know that we’re coming? It turns out, the visual threat is a bigger cue than we may have realized.
The purpose of this study was to examine not only the intricacies of the behavior of the mosquito in response to a threatening shadow, but also to nail down the molecular underpinnings of how mosquitoes are able to detect visual threats. Aedes aegypti, or the Yellow Fever Mosquito, were placed in a cage with a camera to watch their movements. A cue of human odor and temperature was placed on one side of the cage. Onto this side of the cage, the researchers projected moving shadows in various light settings and recorded their behavior. 
Unsurprisingly, the researchers found that mosquitoes attempting to find a host were interrupted by a visual threat, in this case, a shadow. However, the researchers did note that the speed of the shadow greatly influenced the takeoff behavior and interruption of the mosquitoes searching for a host. However, even in the slowest shadow test, the mosquitoes were still likely to take off, with only 30% of the tested mosquitoes remaining stationary. Also unsurprisingly, the visual threat does not stave off the mosquitoes form an area, with many of them returning to their host seeking behavior following a passing shadow. They additionally tested these responses in males and non-host seeking females for a sucrose cue, and they too, take flight at the sign of danger in the form of a shadow.
The researchers also tested the responses of the mosquitoes to the shadows in different lighting conditions and found that mosquitoes were able to avoid the shadows in low-light conditions, suggesting that the Aedes visual acuity may be better than previously thought. This led the researchers to consider what genes may be assisting the mosquitoes in terms of recognition of a visual threat. Using CRISPR Cas-9, a methodology for editing specific genes within an organism, the researchers created mutant mosquitoes that featured tweaks to the TRP, Op1, and Op2 genes. TRP corresponds to the rhabdomeres, which is the light-sensitive part of photoreceptor cells in the eye, and the Op genes correspond to the rhodopsins, which are proteins that assist in how those photoreceptor cells work. The researchers discovered that the trp mutant mosquitoes were no longer sensitive to the movement of the shadows in high-light conditions but could still sense the shadows in low-light conditions. Alternately, the mutant mosquitoes that featured defects in both op1 and op2 were not able to sense the movement of shadows in low-light conditions but could sense the movement of the shadows in high-light conditions. This means that there are multiple genes at work in the tiny photoreceptor cells of Aedes aegypti that are contributing to their ability to recognize a potential visual threat.
Understanding the biology and behavior of Aedes aegypti in how they respond to visual threats could potentially be a brand-new means of mosquito management. Not only does it help us understand their takeoff behavior in response to a visual threat, but it also provides context on how things are functioning in those little eyeballs of theirs. Not to mention, this research could provide a springboard for new innovations utilizing shadows as mosquito repellents. This could be our mission, should we choose to accept it.
Article by Laura Rosenwald, BCE
References
Geoff T. Meyerhof, Pratik Dhavan, Summer Blunk, Allison Bourd, Ramandeep Singh, Avinash Chandel, Craig Montell, Visual threat avoidance while host seeking by Aedes aegypti mosquitoes, Cell Reports, Volume 44, Issue 4, 2025, 115435, ISSN 2211-1247, https://doi.org/10.1016/j.celrep.2025.115435.
Stored Product Pest Management
Direct Lethality and Time-delayed Sublethal Effects of Multiple Types of Insecticide Netting Against Stored Product Insects
Stored product pests are responsible for huge economic losses of our food supply. Insect infestation is estimated to be responsible for 20-30% loss of the world’s cereal. (Grain that is, not just your breakfast food). Within this, movement of pests and dispersal is a huge challenge in IPM. Aka keeping these pests contained and stopping them from contaminating other sources.
The use of LLINs is a logical next step in preventing insect movement amongst stored products. LLIN, long lasting insecticide-incorporated netting is part of many different kinds of IPM plans, you may think of mosquito netting, or you may have heard of using this for bed bugs. It is also used a lot in the agricultural space.
Many researchers over the years took this idea and wanted to see if they could apply it to stored product pests. This paper is a closer look at one of those studies. The researchers here looked at commonly used insecticides for these nets against the red flour beetle and the lesser grain borer.
We know from other recent research that LLINs can be effective on other stored product pests and has had direct lethal and sub-lethal effects such as reduced reproduction in succeeding generations and reduced dispersal. but specifically in this paper they wanted to know the direct lethality effects for the red flour beetle and lesser grain borer and how the LLINs effected their mobility after exposure and other sub-lethal effects. They chose these two insects because the red flour beetle is an external feeder, a strong walker but weak flier and mostly confined to food facilities. Whereas the lesser grain borer is the opposite as an internal feeder, a strong flier, and can disperse long distances. So they were able to look at these polar opposite bugs to see how the nets would work across a diversity of stored product pests.
They treated the pests with three different types of nettings in their own trials. Carifend alpha cypermethrin, d-Terrance deltamethrin, and etofenprox. They also had an untreated control netting. To assess the direct lethality, the beetles were exposed to the netting for 5, 60, or 120 minutes on netting in petri dishes and then they evaluated their conditions as alive, affected, or dead immediately, after 1 day, 3 days, and one week. To be clear, alive beetles were able to right themselves after being flipped and moving with normal speed whereas affected was shown to have “sluggish or drunken movements” unable to right themselves or twitching. And well, dead was dead.
Based on this, the next part of the experiment was baseline mobility post exposure. They needed to establish what the movement patterns were like immediately after exposure. With the alive adults, they tracked the movements of the bugs on either just filter paper, or the different types of netting, or untreated netting. They watched them with a bird eye view style camera over one hour. The program used Ethovision to track the beetle movements over time and find the total distance and speed of them. then they checked this mobility again after 3 days.
To compare the sub lethal movements, the exposed beetles were assessed again for movement with the Ethovision software camera after 3 days post exposure. The sublethal effects were greatest after the three days rather than immediately post exposure so that means it can take a few days for the netting to affect the beetles. The sublethal effects were not as severe when the beetles were only exposed to the netting for a few minutes. 
Overall, it seemed that deltamethrin and alpha cypermethrin were similar in their efficacy against the lesser grain borer but deltamethrin was better against the red flour beetle. But that both are still effective and can be used for direct lethality and sublethal effects.
These results show us that the netting works against two very different stored product pests which is likely to mean it will be effective on other pests on the spectrum between these. It is a promising idea to use the netting against these pests in food commodities in our efforts to protect the world food supply. This gives us insights on methods to be used that will work for preventing the dispersal and ultimately contamination of more food sources which of course ties into all PMP’s mission to protect public health, food, and property.
Article by Ellie Sanders, BCE
References
Sabita Ranabhat, Jennifer Abshire, Avery James, Deanna S Scheff, Georgina V Bingham, Kun Yan Zhu, William R Morrison, Direct lethality and time-delayed sublethal effects of multiple types of insecticide netting against stored product insects, Journal of Economic Entomology, Volume 118, Issue 3, June 2025, Pages 1419–1430, https://doi.org/10.1093/jee/toaf059
Listen to the Episode!
Have questions or feedback for the BugBytes team? Email us at training@pestworld.org, we'd love to hear from you!
