Pestology Blog

We’re learning that spotted lanternfly (SLF) honeydew is turning out to be an all-you-can-eat buffet for a wide range of insects looking to score some easy carbohydrates. And a new publication out of Virginia Tech adds a new pest group to that list that should get every PMP's attention: mosquitoes. 

Mosquitoes need sugar to survive, fly, and reproduce. They're known to be opportunistic about where that sugar comes from, feeding on nectar, fruit, and honeydew from insects such as aphids. So, when researchers doing fieldwork in Lynchburg, Virginia noticed swarms of mosquitoes hanging around trees of heaven loaded with SLF honeydew, they figured it was worth testing whether the mosquitoes were actually feeding on it. 

Over two months in fall 2024, the team trapped mosquitoes near SLF-infested trees of heaven and ran a two-step test on each one. First, they ran a simple color-change assay that checked whether a mosquito had recently fed on sugar at all. Then, for the ones that tested positive, the researchers used SLF-specific DNA barcoding (essentially fishing out trace lanternfly DNA left behind in the honeydew) to confirm whether that sugar meal specifically came from SLF honeydew or some other source. 

Of the 303 mosquitoes collected, which spanned 7 different species including invasive Aedes albopictus and Ae. japonicus, about 1 in 4 (24.8%) tested positive for recent sugar feeding. Of those sugar-fed mosquitoes, 13.3% came back positive for SLF DNA, confirming they'd specifically been feeding on lanternfly honeydew. That included both invasive species like Ae. albopictus and native Aedes and Culex species. That’s an important details because it suggests this honeydew feeding isn't just a quirk of one species, it's a shared opportunity multiple mosquitoes are taking advantage of. 

Of all the information to come out of this study, the timing is what makes this observation interesting. SLF honeydew production peaks in the fall, right around the same window when female mosquitoes of many species are shifting away from blood-feeding and ramping up sugar-feeding to build reserves in preparation to overwinter. That overlap raises the possibility that SLF infestations could be giving local mosquito populations an extra nutritional boost right when they need it most to survive the winter, a connection the authors say deserves additional follow up. 

Another interesting finding in this study was in the chemistry of the SLF honeydew. SLF honeydew's scent is dominated by compounds including isoamyl acetate, which also happens to be a major component of banana scent known to attract Ae. aegypti. That shared chemical signature may explain how mosquitoes are able to sniff out this unfamiliar sugar source even in places where both the lanternfly and the mosquito are themselves invasive newcomers. 

While this was a preliminary study, it gives us one more data point showing how an SLF infestation can ripple outward, potentially impacting other pest species in ways that aren't always obvious.  

The authors even tease the idea of a shared trap strategy that could target both SLF and sugar-seeking mosquitoes using the same lure chemistry. It's early, but it's a reminder that these two high-profile invasive pests may be more connected on the ground than most people realize. 

When it comes to talking about the work that we do as pest management professionals, there has always been a bit of an odd man out. Almost all of the major pests that we deal with as pest management professionals have some connection to public health… except termites. Don’t get me wrong, the damage that they can cause to property can be extremely significant and it’s nothing to sneeze at. Although… a new study out of Taiwan suggests that maybe the termites are the reason why we’re sneezing in the first place. 

Allergens are substances that an immune system recognizes as a threat and generates a response by the body in the form of sneezing, itching, hives, and the list goes on. Pests, such as rodents, bed bugs, and cockroaches are common sources of allergens that have been linked to increased allergic responses as well as asthma. In the past five years, 9 new allergens (for a total of 20!) just from the American Cockroach alone have been added to the list of allergen nomenclature that is approved by both the World Health Organization and the International Union of Immunological Societies.  

But let’s pause for a minute and remember which group was recently described as taxonomically related to cockroaches… any guesses? That’s right- termites. The researchers hypothesized that due to the close relationship between termites and cockroaches there may be some similarities between their abilities to make our immune systems go haywire.  

Using Formosan subterranean termites and Asian subterranean termites along with American cockroaches as a comparison, the researchers extracted allergens for testing. The researchers also separately tested the alates, workers, and soldiers of each termite species. The researchers then went through a battery of tests including skin prick tests on humans, detection assays, immunoblotting assays, and sequencing of the termite allergens found in this study.  

The researchers first began by comparing the cross-reactivity of termites versus cockroaches. In other words, were there allergens that cockroaches are known to have that termites also share? Turns out yes! There are shared allergens between cockroaches and termites which could trigger immune responses in humans. This includes two of the major allergen players: tropomyosin and arginine kinase. In addition, the researchers also noted that some of these allergens were only expressed in alates, and were not expressed in the workers and soldiers.  

Looking at the human reaction of the allergens in this study, out of the 16 people who volunteered who had a history of exposure to termites, 8 featured a positive skin reaction in an allergen test of Formosan subterranean termites and 6 featured a positive skin reaction in an allergen test of Asian subterranean termites.  

Through further immunological studies, the researchers were able to determine the specific amino acid sequences of these substances based on how the body was reacting, and found three suspects: Copt f 7, Copt f 9, and Copt f 3. They were then able to sequence these allergens and found that Copt f 7, the termite version of tropomyosin, had a 99-100% similarity with American cockroach and German cockroach tropomyosin and an 80-83% similarity with shrimp and mite tropomyosin. Copt f 9, or the termite arginine kinase, shared a 98% similarity with the cockroach versions and an 83-91% similarity with the shrimp and mite versions. Copt f 3, which was the hemocyanin-like protein was the most unique to termites, as it only shared 57-61% similarity in make-up to the cockroach versions. The researchers were able to conclude that these allergens are all extremely similar, and therefore likely induce the same kind of allergic reactions.  

Overall, this study provided clear and convincing evidence that termites are, and should be, considered as a public health pest that may be an indoor allergen source. These researchers identified at least three new allergens that termites can release into the environment, and ones that we know share similarities to allergens that have already been well-documented.  Truly nothing to sneeze at.