Chewing lice richness and occurrence in non-breeding shorebirds in Paracas, Perú

Chewing lice often appear benign; however, they can also negatively impact their hosts. We know little about seasonal and spatial variation in the exposure, acquisition, or loss of these putative ectoparasites by shorebirds. Here we provide the first description of chewing lice richness and occurrence from seven shorebird species captured in the Paracas National Reserve, Perú. We summarize seasonal patterns of abundance, and test for relationships between parasite numbers and shorebird body condition. We collected 160 ectoparasite specimens of the families Menoponidae and Philopteridae from 108 shorebirds and classified them into four genera and at least nine species. The Philopteridae family showed higher prevalence (62%), richness, and number of host species (seven parasitic species being hosted by seven shorebird species) than the Menoponidae (prevalence = 49%; two parasitic species in five host species). Among species, Actornithophilus umbrinus, found on all four Calidris species, had the highest number of hosts, while A. pediculoides and all the Philopteridae species were only found on a single host. Lunaceps actophilus had the highest prevalence, mean intensity, and mean abundance of infection, being found on 64% of the Sanderlings Calidris alba. Sanderlings hosted the highest abundance of lice, whilst Semipalmated Sandpipers C. pusilla had the highest richness. In Sanderlings, we found an apparent, but not statistically significant, decrease in parasite loads through the nonbreeding season. Sanderling body condition varied with capture period, but we found no significant relationship between body condition and total parasites within each time period or in pooled analysis by date. Paracas appears to be a site at which shorebirds maintain or possibly slightly shed the loads of chewing lice rather than acquire them; these low parasite loads do not appear to negatively affect body condition.