of a preventative measure to ward off insects. Additionally, another species of titi monkeys, Plecturocebus cupreus, were seen rubbing their furs with the leaves of Psychotria, whose compounds have antiviral, antifungal, and analgesic properties. Birds More than 200 species of song birds wipe ants, a behaviour known as anting. Birds either grasp ants in their bill and wipe them vigorously along the spine of each feather down to the base, or sometimes roll in ant hills twisting and turning so the ants crawl through their feathers. Birds most commonly use ants that spray formic acid. In laboratory tests, this acid is harmful to feather lice. Its vapour alone can kill them. Some birds select nesting material rich in anti-microbial agents that may protect themselves and their young from harmful infestations or infections. European starlings (Sturnus vulgaris) preferentially select and line their nests with wild carrot (Daucus carota); chicks from nests lined with this have greater levels of haemoglobin compared to those from nests which are not, although there is no difference in the weight or feather development of the chicks. Laboratory studies show that wild carrot substantially reduces the emergence of the instars of mites. House sparrows (Passer domesticus) have been observed to line their nests with materials from the neem tree (Azadirachta indica) but change to quinine-rich leaves of the Krishnachua tree (Caesalpinia pulcherrima) during an outbreak of malaria; quinine controls the symptoms of malaria.<ref>{{cite web| vauthors = Ichida J |publisher=Proceedings of the 104th General Meeting of the American Society for Microbiology|url=http://www.scienceblog.com/cms/node/2776|title=Birds use herbs to protect their nests, BJS, Science Blog, Wed, 2004-05-26|date=2004-05-26}}</ref> Social zoopharmacognosy Zoopharmacognosy is not always exhibited in a way that benefits the individual. Sometimes the target of the medication is the group or the colony. Wood ants (Formica paralugubris) often incorporate large quantities of solidified conifer resin into their nests. Laboratory studies have shown this resin inhibits the growth of bacteria and fungi in a context mimicking natural conditions. The ants show a strong preference for resin over twigs and stones, which are building materials commonly available in their environment. There is seasonal variation in the foraging of ants: the preference for resin over twigs is more pronounced in spring than in summer, whereas in autumn the ants collect twigs and resin at equal rates. The relative collection rate of resin versus stones does not depend on infection with the entomopathogenic fungus Metarhizium anisopliae in