Avian malaria is a vector transmitted disease caused by Plasmodium and recent studies suggest that variation in its prevalence across avian hosts is correlated with a variety of ecological traits. Here we examine the relationship between prevalence and diversity of Plasmodium lineages in southeastern Amazonia and: (1) host ecological traits (nest location, nest type, flocking behaviour and diet); (2) density and diversity of avian hosts; (3) abundance and diversity of mosquitoes; and (4) season. We used molecular methods to detect Plasmodium in blood samples from 675 individual birds of 120 species. Based on cytochrome b sequences, we recovered 89 lineages of Plasmodium from 136 infected individuals sampled across seven localities. Plasmodium prevalence was homogeneous over time (dry season and flooding season) and space, but heterogeneous among 51 avian host species. Variation in prevalence among bird species was not explained by avian ecological traits, density of avian hosts, or mosquito abundance. However, Plasmodium lineage diversity was positively correlated with mosquito abundance. Interestingly, our results suggest that avian host traits are less important determinants of Plasmodium prevalence and diversity in southeastern Amazonia than in other regions in which they have been investigated.

Neotropical Entomology 36(6): 960-965 (2007) Abundance and Aggregation Egg of Aedes aegypti L. and Aedes albopictus (Skuse) (Diptera: Culicidae) in the North PALAVRAS-CHAVE: Ecologia de vetores, armadilha de oviposição, dengue, espécie invasora, mosquitoAedes aegypti L. e Aedes albopictus (Skuse) são espécies exóticas e simpátricas, a primeira com longo histórico de ocorrência no Brasil e a segunda com introdução notifi cada em 1986 (Forattini 1986). Ae. aegypti é considerada o único vetor do arbovírus da dengue e da dengue hemorrágica nas Américas. Ae. albopictus não possui papel relevante como vetor de arbovírus para o Brasil, porém experimentalmente mostrou-se capaz de infectar-se e transmitir o vírus DEN-2 da dengue (Castro et al. 2004). Podemos, no entanto, indicar que ambas as espécies exercem hematofagia no ambiente antrópico, sendo a primeira encontrada mais frequentemente no ambiente intradomiciliar e a segunda no ambiente extra-domiciliar (Gomes et al. 2005).As duas espécies podem coexistir na mesma região e utilizam criadouros de características semelhantes. Colonizam rapidamente locais onde as condições são favoráveis para sua proliferação e, embora as fêmeas não percorram grandes distâncias, sua dispersão é rápida dependendo da disponibilidade de sítios para oviposição (Forattini 2002, Braks et al. 2003, Lounibos 2002.No monitoramento das populações de mosquitos são utilizadas armadilhas para ovos (ovitrampas). Estas permitem determinar a dispersão geográfi ca, densidade, freqüência, ocupação, dominância e sazonalidade, porém não permitem quantificar o número de fêmeas que utilizarão essas

Determining the roles of host ecology and geography on the distribution of parasites is an important aim in disease ecology. However, this is extremely challenging for vector transmitted pathogens due to complex host-vector-parasite interactions. Here, we assess community turnover of birds, ornithophilic mosquitoes and Plasmodium parasites at different dimensions of diversity (taxonomic, functional and phylogenetic). We test if rivers can act as a geographic barrier to bird, mosquito and Plasmodium communities, and analyze the relationship among community turnover of these biological groups. We compiled two published datasets on bird, mosquito and Plasmodium communities collected in seven localities across the Tapajós river in southern Amazonia. We calculated the community turnover of bird, mosquito and Plasmodium communities, and identified the effect of river margin on community composition by comparing observed values with null models. Mantel tests were used to examine the different turnover dimensions within this host-vector-parasite system. Bird communities on the same riverbank were more similar, whereas bird phylogenetic turnover between riverbanks was more dissimilar than expected by chance. Neither mosquito nor Plasmodium turnover showed significant turnover between riverbank margins. We found a positive correlation between bird community turnover, both taxonomic and functional, and mosquito community turnover. Bird community taxonomic turnover was also positively related to Plasmodium community phylogenetic turnover. Our results suggest that geographic barriers created by the Tapajós river affect bird community assembly but do not constrain mosquito and Plasmodium distributions. Additionally, bird communities may play a key-role in the community dynamics of mosquito vectors and Plasmodium parasites.

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