For a lesson in euphoria, look no further than a house cat twined around a twig of silver vine. When offered a snipping of the plant, which contains chemicals similar to the ones found in catnip, most domesticated felines will purr, drool and smoosh their faces into its intoxicating leaves and stems, then zonk out in a state of catatonic bliss.
But the ecstatic rush might not be the only reason felines flock to these plants, new research suggests. Compounds laced into plants like silver vine and catnip might also help cats ward off mosquitoes.
Other papers have pointed to the insect-deterring effects of catnip and similar plants. But the new study, published recently in the journal Science Advances, is the first to draw a direct link between the plants and their protective effects on cats.
“It’s a really interesting observation, that such a well-known behavior could be having this unappreciated benefit for cats,” said Laura Duvall, a mosquito researcher at Columbia University in New York who wasn’t involved in the study.
Catnip and silver vine contain iridoids, a suite of chemicals that seem to potently tickle pleasure circuits in cats.
To pinpoint the evolutionary roots of this plant-feline connection, a team of researchers led by Masao Miyazaki, a biochemist and veterinary scientist at Iwate University in Japan, corralled a menagerie of cats — some domestic, some wild — and monitored their responses to an iridoid extracted from silver vine.
Presented with scraps of paper dosed with iridoid, most of the cats initiated a ritualized rolling and rubbing.
The researchers next rubbed silver vine iridoids on the heads of several house cats, or allowed the felines to apply the substance themselves, and placed the animals within reach of dozens of thirsty mosquitoes. The insects nipped at the faces of unanointed cats, but largely snubbed the felines that had gone gaga for the vines.
The new findings suggest that cats, which can contract heartworm infections from mosquito bites, might also glean some medicinal benefits from their botanical tussles, said Mikel Delgado, a cat behavior expert at the University of California, Davis who wasn’t involved in the study.
In a one-off experiment, Miyazaki slathered his arm with iridoids and stuck it in a mosquito cage. The insects steered clear — but feasted on an untreated limb. “We hope to use it for humans in the future,” he said.
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