"Body lice" refers to tiny insects that live on human bodies and feed on blood. They can cause itching and discomfort and are often found in unclean or crowded living conditions. Full definition
Most species of body lice infest only one species of bird host, whereas each wing lice species generally infests several species of bird. (sciencemag.org)
Re # 2: [If human body lice studies are confirmed as indicating that not a single human wore clothing, not even animal skins, as recently as 169,000 years ago, then the average temperature globally must have been considerably warmer...] (realclimate.org)
Christopher Harbison and Dale Clayton, evolutionary biologists at the University of Utah in Salt Lake City, wondered whether another bug, the parasitic hippoboscid fly, could explain how body lice get around more. (sciencemag.org)