1. Interspecific competition influences which, how many and where species coexist in biological communities. Interactions between species in different trophic levels can mediate interspecific competition; e.g. predators are known to reduce competition between prey species by suppressing their population sizes. A parallel phenomenon may take place in host-parasite systems, with host defence medi...

Background Alpacas (Vicugna pacos), earlier named Lama pacos, belong to the family Camelidae of which there are 7 living species. Four are native to South America and of those four two are domestic species, the alpaca (Vicugna pacos) and the llama (Lama glama) and two are wild, the vicuña (Vicugna vicugna) and the guanaco (Lama guanicoe). These species are often referred to as the New World cam...

1. For iteroparous organisms life-history theory predicts a trade-off between current and future reproduction, and therefore the evolution of host responses to current parasite infestation that will maximize lifetime reproductive success. The parasite-induced variation in reproductive success is thus not the net result of parasite infestation alone, but the parasite-mediated outcome of optimal ...

Fifty-eight white-necked ravens (Corvus cryptoleucus) were examined for ectoparasites. Brueelia afzali and Philopterus ocellatus osborni were the most abundant mallophagans while Colpocephalum fregili and Myrsidea interruptus were the least common. The white-necked raven is listed as a new host for P. ocellatus osborni. Host sexual selection is indicated by statistical treatment of data obtaine...