Ectoparasites of small-mammals: determinants of community structure in South American savannah.

This study aimed to assess the contribution of hosts characteristics (rodents and marsupials) in the organization of ectoparasite communities present in woodland patches in western central Brazil. We verified the effect of host species, sex, body mass and vertical strata in addition to the role of seasonality on the ectoparasite composition, richness and abundance. The total sampling effort was 22 032 trap-nights equally distributed in 54 woodland patches. Variance partition and principal coordinate analysis were used to verify the existence of significant relationships between response variables and predictors. As expected, host species was the most important variable in ectoparasite community assembly. The composition, richness and abundance of mites and lice were highly influenced by host species, although higher for mites than for lice. Host body mass had a determining role on the richness and abundance of tick species. Vertical stratification and seasonality had weak influence, while the sex of the host had no influence on the organization of these communities. The results are closely related to the evolutionary characteristics of the species involved, as well as with local environmental characteristics of the study area.

The role of melanism in oncillas on the temporal segregation of nocturnal activity / O papel do melanismo na segregação temporal da atividade noturna do gato-do-mato-pequeno

The occurrence of coat colour polymorphisms in populations may promote the ecological success of species by permitting a wider spectrum of use of different subsets of available resources. We conducted an analysis of temporal segregation by comparing night brightness with nocturnal activity of spotted and melanistic oncillas (Leopardus tigrinus). Melanistic oncillas were more active during bright nights and spotted oncillas and other species were more active during dark nights. Each colour morph occupied a temporal niche outside the confidence interval of the other colour morph, demonstrating the ecological significance of polymorphic colour patterns in this felid species.(AU)

A ocorrência de polimorfismo no padrão de pelagem de populações pode promover o sucesso ecológico das espécies por permitir um amplo espectro de uso de diferentes parcelas de recursos disponíveis. Nós testamos a existência de diferença na segregação temporal do gato-do-mato-pequeno (Leopardus tigrinus), comparando a luminosidade durante períodos de atividade noturna de indivíduos pintados e melânicos. Indivíduos melânicos de gato-do-mato-pequeno foram mais ativos durante noites claras e indivíduos pintados de gato-do-mato-pequeno e outras espécies foram mais ativas durante noites escuras. Cada forma de coloração ocupou um nicho temporal fora do intervalo de confiança do outro, demonstrando a significância ecológica dos padrões de polimorfismo de colorações nesta espécie de felino.(AU)

The role of melanism in oncillas on the temporal segregation of nocturnal activity.

The occurrence of coat colour polymorphisms in populations may promote the ecological success of species by permitting a wider spectrum of use of different subsets of available resources. We conducted an analysis of temporal segregation by comparing night brightness with nocturnal activity of spotted and melanistic oncillas (Leopardus tigrinus). Melanistic oncillas were more active during bright nights and spotted oncillas and other species were more active during dark nights. Each colour morph occupied a temporal niche outside the confidence interval of the other colour morph, demonstrating the ecological significance of polymorphic colour patterns in this felid species.