We evaluated and compared these alternative feeding behaviors in relation to feeding kinematics and the shape of the mouth with high-speed digital imaging. VX-770 We tested the hypotheses that (1) L. labyrinthicus tadpoles use functionally different feeding kinematics when feeding on alternative food sources and (2) that the jaw sheaths of L. labyrinthicus tadpoles deform less during filter-feeding and substrate grazing compared with more common tadpoles not so specialized for macrophagous

carnivory. Our results show that filtering and scraping feeding behaviors differ significantly in both kinematics and shape of the mouth. During filter-feeding, tadpoles display longer gape cycles and attain a narrower maximum gape earlier in the cycle compared

with substrate grazing. Jaw deformation during opening and closing phases of the gape cycle is more pronounced during grazing on firm substrates. This deformation contributes to the achievement of a wider maximum gape during feeding. These differences appear to reflect behavioral adjustments by the tadpoles to maximize food intake. Feeding in tadpoles BMS-777607 concentration of L. labyrinthicus is not restrained by their typical carnivorous morphology. On the contrary, L. labyrinthicus tadpoles seem to be opportunistic feeders able to obtain nutrients from a variety of food sources by using different feeding strategies. “
“Patterns of infection and prevalence result from complex interactions between hosts and parasites, the effects of which are likely to vary by species. We investigated the effects of age, sex and season on the likelihood of individual infection, and the effects of host population size, sex ratio and age structure on parasite prevalence. We capitalized on data from a

long-term study of yellow-bellied marmots Marmota flaviventris potentially infected with fecal–orally transmitted intestinal Acetophenone parasites (Ascaris sp., Eimeria spp. and Entamoeba sp.), ectoparasitic fleas Thrassis stanfordi, and a flea- and louse-transmitted blood parasite Trypanosoma lewisi. Patterns of individual- and group-level infection varied widely by parasite. Yearlings were more likely to be infected with Tr. lewisi and Ascaris. Yearlings were also slightly more likely than adults to have Eimeria, but female yearlings had higher infection levels than female adults, while male yearlings had lower infection levels than male adults. Entamoeba infection decreased as the season progressed. Adults and males were more likely to be infected with Th. stanfordi. Ascaris prevalence increased with colony size. There were no significant relationships between colony size and prevalence of Entamoeba, Tr. lewisi, Eimeria or Thrassis. There was a small, but significant positive correlation between male-biased sex ratio and prevalence of fleas. The host population’s age structure affected the prevalence of infection of Ascaris and Eimeria.