The Widow's (and Everyone Else's) Mite

Mites are tiny relatives of spiders. One species, Domodex folliculorum, looks like a tiny dachsund and lives on the skin of 90% of humans (https://www.theguardian.com/science/2022/jun/22/tiny-mites-demodex-folliculorum-parasites-gene-loss). Domodex folliculorum feeds on sebum, a fatty secretion from our skin pores. These tiny beasts emerge at night, to mate on our foreheads, noses and nipples. Genome sequencing of Domodex folliculorum has revealed, however, that this mite has a smaller repertoire of proteins than is seen any other invertebrate. Domodex folliculorum's progressive loss of genes (you need a gene for each protein that is produced), suggests an evolutionary 'dead end' with potential extinction for our tiny companions.