A natural repellent for felids
20 September 2021 – News
Felids display a typical behavioral response associated to the sniffing of specific plants, such as catnip and silver vine. This reaction is well-known and includes licking and chewing the plants, face and head rubbing against the plants, and rolling over on the ground. However, the neurophysiological mechanism and biological function associates is still uncertain – the aim of this study was to uncover them.
Both plants contain bioactive iridoid compounds. It is known that catnip has nepetalactone and, the authors found, nepetalactol is the major component of silver vine that elicits this behavior.
In this investigation, various studies were performed to evaluate felids response to bioactive iridoids. Both laboratory cats and free-range feral cats were used. When compared to placebo, cats that commonly respond to these plants (positive responders), have shown to be more likely to exhibit face rubbing and rolling towards nepetalactol-impregnated filter paper than towards the control-paper. When evaluating the response to different bioactive iridoids, nepetalactol (silver vine) and nepetalactone (catnip) induced more prolonged reactions than other iridoids.
It was also demonstrated that the mu-opioid system is involved in the induction of the feline behavioral response: not only nepetalactol increased plasma mu-endorphin levels in cats, but also pharmacological inhibition of mu-opioid receptors suppressed the classic rubbing response. Additionally, the authors suggest that cats might have acquired specific olfactory receptor(s) that detect nepetalactol and other iridoids emitted from some plants with high sensitivity.
Another interesting conclusion was that rubbing and rolling response against silver vine leaves allows the transfer of nepetalactol to cats’ face and head fur, functioning as a repellent against A. albopictus (a mosquito species). As such, nepetalactol may be a new natural candidate repellent to help reduce mosquito problems in human society.
Uenoyama, R., Miyazaki, T., Hurst, J. L., Beynon, R. J., Adachi, M., Murooka, T., Onoda, I., Miyazawa, Y., Katayama, R., Yamashita, T., Kaneko, S., Nishikawa, T., & Miyazaki, M. (2021). The characteristic response of domestic cats to plant iridoids allows them to gain chemical defense against mosquitoes. Science advances, 7(4), eabd9135. https://doi.org/10.1126/sciadv.abd9135