The characteristic response of domestic cats to plant iridoids allows them to gain chemical defense against mosquitoes

ネコのマタタビ反応の謎を解明 --マタタビ反応はネコが蚊を忌避するための行動だった--. 京都大学プレスリリース. 2021-01-21.Domestic cats and other felids rub their faces and heads against catnip (Nepeta cataria) and silver vine (Actinidia polygama) and roll on the ground as a characteristic response. While this response is well known, its biological function and underlying mechanism remain undetermined. Here, we uncover the neurophysiological mechanism and functional outcome of this feline response. We found that the iridoid nepetalactol is the major component of silver vine that elicits this potent response in cats and other felids. Nepetalactol increased plasma β-endorphin levels in cats, while pharmacological inhibition of μ-opioid receptors suppressed the classic rubbing response. Rubbing behavior transfers nepetalactol onto the faces and heads of respondents where it repels the mosquito, Aedes albopictus. Thus, self-anointing behavior helps to protect cats against mosquito bites. The characteristic response of cats to nepetalactol via the μ-opioid system provides an important example of chemical pest defense using plant metabolites in nonhuman mammals

Domestic cat damage to plant leaves containing iridoids enhances chemical repellency to pests

Catnip (Nepeta cataria) and silver vine (Actinidia polygama) produce iridoids with arthropod-repellent effects. Cats rub and roll against these plants, transferring iridoids to their fur that repels mosquitoes. Cats also lick and chew plant leaves during this response, although the benefit of this additional behavior has remained unknown. Here, we show that feline leaf damage substantially increases iridoid emission from both plants while also diversifying iridoids in silver vine. Cats show an equivalent duration of response to the complex cocktail of iridoids in damaged silver vine and to the much higher level of a single iridoid produced by damaged catnip. The more complex iridoid cocktail produced when silver vine is licked and chewed by cats increases mosquito repellency at low concentration. In conclusion, feline leaf damage contributes by releasing more mosquito-repellent iridoids. Feline olfactory and behavioral sensitivity is fine-tuned to plant-specific iridoid production for maximizing the mosquito repellency gained

Assessing the safety and suitability of using silver vine as an olfactory enrichment for cats

Summary: Olfactory enrichment is a strategy that can improve welfare among animals managed in captivity, such as household domestic cats. Catnip (Nepeta cataria) and silver vine (Actinidia polygama) that produce iridoids are used as olfactory enrichments for cats, but little is known about the safety or the best plant resources to use that maximize positive cat responses. We report physiological effects and suitable harvest and drying methods for using silver vine as olfactory enrichment. Continuous exposure of cats to silver vine showed no hallmarks of addictive behavior, while blood indicators of stress and hepatic or renal injury showed no increase in cats stimulated with it. Drying the leaves changed the iridoid profile, enhancing the feline response. In conclusion, dried silver vine leaves are the most suitable resource for developing olfactory enrichment that maximizes feline typical response, which would not result in dependence, stress, or toxicity to the liver or kidneys in cats

Identification of 2-phenylethanol with a rose-like odor from anal sac secretions of the small Indian mongoose (<i>Herpestes auropunctatus</i>)

<p>The small Indian mongoose (<i>Herpestes auropunctatus</i>) is an invasive species in Okinawa and Amami-Oshima, Japan. Major strategies for their eradication have been the use of baited traps, which suffer from decreasing efficiency with declining populations and the bycatch of native animals. To address these concerns, mongoose-specific lures are required. In this study, we aimed to identify species- and/or sex-specific compounds from anal sac secretions of small Indian mongooses. Volatile compounds emitted from male and female mongoose anal sac secretions were analyzed by thermal desorption-gas chromatography-mass spectrometry. In addition to several fatty acids, 2-phenylethanol was identified as a minor compound, which is uncommon in mammalian secretions but a dominant odorant in roses. Female samples emitted higher levels of 2-phenylethanol than male samples did. These findings indicate that 2-phenylethanol is a female-specific volatile compound of anal sac secretions in small Indian mongooses, and it may be useful as an ingredient of mongoose-specific scent lures.</p> <p>2-Phenylethanol is an indicator of female anal sac secretions in small Indian mongooses.</p