Protocalliphora or bird blowflies are a blow fly genus containing many species which are obligate parasites of birds. The larvae suck the blood of nestlings and are found in the nests of birds. The genus is affected by Wolbachia

Wolbachia

Wolbachia is a genus of bacteria which infects arthropod species, including a high proportion of insects , as well as some nematodes. It is one of the world's most common parasitic microbes and is possibly the most common reproductive parasite in the biosphere...

bacteria and it has been suggested that horizontal gene transfer

Horizontal gene transfer

Horizontal gene transfer , also lateral gene transfer , is any process in which an organism incorporates genetic material from another organism without being the offspring of that organism...

 may have led to the difficulty in separating species of Protocalliphora through DNA fingerprinting, with several species possessing identical mtDNA Cytochrome oxidase I

Cyclooxygenase

Cyclooxygenase is an enzyme that is responsible for formation of important biological mediators called prostanoids, including prostaglandins, prostacyclin and thromboxane. Pharmacological inhibition of COX can provide relief from the symptoms of inflammation and pain...

sequences.

They sometimes feed inside the nostrils of nestling birds and destroy the tissue at the base leading to reduced growth of the upper mandible and the young growing with "shovel-beaks".