267 - From Russia with Parasites

·1 hr 3 min·5 clips

How does a parasite make a rat lose its fear of cat urine, leading to fatal attraction?

The episode begins with hosts Ryan and Kelly Wienersmith introducing the theme 'From Russia with Parasites' and their guest Misha Gopko, a PhD student at the Severtsov Institute of Ecology and Evolution in Moscow. Misha's research focuses on parasite manipulation, where parasites alter host behavior to enhance their own transmission. He explains the concept using the extended phenotype theory by Richard Dawkins. A key example discussed is Toxoplasma gondii, which makes rats lose their aversion to cat urine, increasing predation. Misha's own system involves the trematode Diplostomum pseudospathaceum, which has a three-host life cycle: snails, fish, and birds. In fish, the parasite lodges in the eye lenses, potentially causing vision deterioration. Through experiments with rainbow trout, Misha found that immature parasites reduce fish activity and depth preference to avoid predators, while mature parasites increase activity and surface swimming to attract bird predators. He also discusses pilot studies showing that when both immature and mature parasites are present, the mature ones dominate behavior. The conversation delves into mechanisms, suggesting chemical signaling beyond just cataracts, and hints at costs of manipulation where parasites may sense population density within the eye. Misha shares future research directions, including predation on free-living parasite stages by mussels and climate change impacts on parasite ecology. The hosts interject with a segment on what they're drinking, featuring water and home fermentation projects, and later read listener feedback. The episode concludes with plugs for Kelly's upcoming book 'Soonish' and Ryan's audio essay on outdoors imposter syndrome.

As heard by us

A warm, wandering science chat where vodka etymology and pineapple fermentation turn everyday details into odd little facts.

Episode 267 starts with Ryan and Kelly Wienersmith circling the heat in the DMV and Houston before wandering into the strange sound of phrases like "learn them" and "itch it." The appeal is less a tidy argument than the way their back-and-forth keeps opening little doors: a…

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Why you'd press play

Press play when you want vodka etymology, pineapple fermentation, and easy banter about usage quirks like learning, itching, and scratching.

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