Lice evolved with birds and mammals

Parasites are thought to diversify with their host species, but the theory has rarely been tested. Kevin Johnson at the University of Illinois and his colleagues sequenced the genomes of 46 species of lice that parasitise birds or mammals, and two non-parasitic bark lice, and constructed an evolutionary tree. They estimated that parasitic lice first emerged between 90 and 100 million years ago, but didn’t begin to diversify until 66 million years ago – around the time of the dinosaurs’ extinction.

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Ants immunise their young

As I’ve mentioned before, living in a large densely-packed social group, like a city or an ant colony, comes with some drawbacks – perhaps worst of which is the risk of catching a contagious diseases. Earlier this year I wrote about research showing that raider ants treat injured workers’ wounds, helping them to heal. Now, a new study shows that the queen can pass on resistance to diseases she’s encountered, arming her workers against pathogens.

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Sedentary hunter-gatherers domesticated mice

House mice outcompeted their wild relatives to become domesticated as soon as long-term human settlements appeared, some 5000 years before agriculture took hold.

The advent of farming marks a huge change in human populations – a change in diet, social structure and a switch to a more sedentary lifestyle. Agriculture also had a profound impact on wild animals, and is thought to have led to the domestication of many species, from wolves to cattle and chickens. But other species became domesticated accidentally – as humans started storing grain for lengthy periods of time, the house mouse adapted to thrive in this new ecosystem. Now, a new study shows that it was our sedentary lifestyle, not agriculture, that domesticated one of our most prolific pests.

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The first skeletons evolved repeatedly in chalky seas

The first skeletons evolved multiple times independently because of unusually chalky seas, later becoming essential for survival even when chalk became scarce.

Calcium-based skeletons appeared suddenly in the fossil record around 550 million years ago, fundamentally changing the global carbon cycle and introducing a wealth of new predatory strategies to the sea.

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