Have you ever wished for a natural way to keep pesky ticks at bay? Researchers at the University of Massachusetts Amherst might just have the answer! Their exciting discovery about the unique properties of donkey skin secretion could pave the way for a revolutionary tick repellent that’s both effective and environmentally friendly.

At the heart of this research is the notorious Ixodes scapularis—better known as the deer tick. This little pest is responsible for transmitting serious diseases like Lyme disease, making tick repellents more crucial than ever. Currently, most repellents are made with chemicals like DEET, which can be effective but not always ideal for everyone.
As Stephen Rich, a microbiologist at the Massachusetts Center of Excellence in Vector-borne Diseases, noted, many people are on the hunt for more natural alternatives. Enter (E)-2-octenal, a compound secreted by donkeys that has been shown to successfully repel these troublesome ticks. Eric Siegel, a lead researcher and doctoral student, explained that different ticks have unique feeding habits, often depending on their hosts.
What makes this donkey secretion stand out is its allomone properties—chemical signals that influence the behavior of different species. Previous research indicated that horses are often prey for ticks, but by masking their scent with (E)-2-octenal, the ticks are thrown off and do not recognize horses as suitable hosts anymore!
In laboratory experiments, the research team demonstrated that ticks could be effectively deterred from moving to areas where (E)-2-octenal was applied. Surprisingly, it was found to be as effective, if not more so, than traditional repellents like DEET. This discovery even revealed that male deer ticks reacted more strongly to the compound than females—an interesting twist in the story!
One of the heartwarming aspects of this study is that four high school students contributed to the research. During a summer program, they were hands-on in setting up preliminary experiments, showcasing the importance of youth involvement in science. Their collaboration with seasoned researchers not only enriched their experience but also demonstrated the power of teamwork.
Now, as the researchers collaborate with Gearjump Technologies, they’re excited about the potential applications of (E)-2-octenal. Beyond creating a tick repellent for humans, the aim is to develop a product that could also help manage deer populations—making this discovery beneficial for both nature and our communities.
As Siegel pondered, could the future hold an environmentally friendly solution to dissuade ticks from invading our outdoor spaces? With ongoing research, we just might find out!
More information:
Eric L. Siegel et al, Exploiting a natural instance of vertebrate-posed chemical aposematism for tick bite prevention: Repellency of Ixodes scapularis with (E)-Oct-2-enal, PLOS ONE (2025). DOI: 10.1371/journal.pone.0317975
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