First ‘Louse’ on Mammals Possibly Started Out as Parasite; How Do Lice Spread to Other Animals?

New research recently showed that the first "louse" to take up dwelling on a mammalian host likely began as the birds' parasite.

A EurekAlert! report said that host-jumping tens of millions of years back started the long link between lice and mammals, setting the stage for their coevolution and providing more opportunities for the lice to spread to other animals, mammals, in particular.

This study compared the genomes and genomes and the family trees of lice and their mammalian hosts. The initiative revealed that the two trees share a lot of parallel branches and twigs.

The researchers reported those branching points; the site one mammal group started diverging into new forms, frequently echoed in the lice's genomes that parasitized such mammals.

Lice in Afrotheria

In this paper published in the Nature Ecology and Evolution journal, the researchers used data from genome sequencing to show that a major newly recognized group of mammalian lice, including human lice, originated on Afrotheria's common ancestor.

Afrotheria is a group of mammals, mainly of African distribution, including hyraxes, elephants, and shrews, among others, according to principal research scientist Kevin Johnson, an ornithologist at the Illinois Natural History Survey who led the research with Jorge Doña, a Marie Curie, a post-doctoral researcher at the Universit of Illinois Urbana-Champaign and the University of Granada, Spain.

The said lice then continued colonizing other major groups of mammals through host switching.

The Chewing and Sucking Lice

Lice fall under two groups according to their habits. One group belongs to the chewing lice that munch on secretions or skin. While sucking, lice are piercing the skin to consume the blood of their hosts, said Johnson. Both lice types feed on mammals, although sucking lice are exclusive to mammals.

Recent studies on genomes showed that sucking lice are closely related to groups of chewing lice that feed as well on mammals, and each of the major groups within this newly identified lineage takes place on at least one Afrotheria member, the researchers wrote.

That study proposed that members of Afrotheria were the original mammalian hosts of lice; Doña and Johnson expanded the genomic sampling of mammalian louse genomes to include more lice linked to Afrotheria and compared the mammals' evolutionary history, including their lice.

The study suggested that Afrotheria members were the original mammalian hosts of lice. They specifically included lice from hyraxes and elephant shrews.

Mammalian Lice

The researchers analyzed that the lice of elephants and elephant shrews were found to be the most ancient in the group of sucking and chewing lice that fed on mammals.

According to Johnson, this presents that these mammalian lice began in this odd group of African mammals and switched to other mammals following that.

How switching from birds to mammals was unusual, added Johnson. The researchers discovered that this occurred just a few times, in Madagascan lemurs, South American rodents, and some marsupials, for instance.

However, a similar TurniseSoir News report said that once lice learned how to feed on mammals, they could jump more easily from one mammal species to another and possibly have more opportunities.

Related information about coevolution is shown in Michael Flood's YouTube video below:

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