Philopterids

Philopteridae is a large and diverse family of chewing lice (Phthiraptera) that are obligate ectoparasites of birds. These tiny insects, also known as feather lice, are found on virtually every species of bird worldwide. Their primary food source is feather material, though some species may also consume skin debris. Philopterids exhibit a high degree of host specificity, meaning a particular species of louse is often adapted to live on only one or a few closely related bird species. This specialization has led to a remarkable evolutionary radiation within the family, mirroring the diversity of their avian hosts.

The life cycle of philopterids consists of three stages: egg, nymph, and adult. The eggs are laid on the feathers of the host bird and hatch into immature nymphs. These nymphs molt several times before reaching adulthood. Adult philopterids are wingless and flattened, with strong legs adapted for clinging to feathers. Their mouthparts are designed for chewing and scraping. Transmission between birds typically occurs through direct contact, such as during preening or nesting. While generally not considered harmful to healthy birds, heavy infestations can cause feather damage, irritation, and in some cases, anemia, particularly in young or weakened individuals. Studies of philopterids provide valuable insights into avian evolution, host-parasite interactions, and biogeography.