Background: The forests of the upper Amazon basin harbour some of the world's highest anuran species richness, but to date we have only the sparsest understanding of the distribution of genetic diversity within and among species in this region. To quantify region-wide genealogical patterns and to test for the presence of deep intraspecific divergences that have been documented in some other neotropical anurans, we developed a molecular phylogeny of the wide-spread terrestrial leaflitter frog Eleutherodactylus ockendeni (Leptodactylidae) from 13 localities throughout its range in Ecuador using data from two mitochondrial genes (16S and cyt b; 1246 base pairs). We examined the relation between divergence of mtDNA and the nuclear genome, as sampled by five speciesspecific microsatellite loci, to evaluate indirectly whether lineages are reproductively isolated where they co-occur. Our extensive phylogeographic survey thus assesses the spatial distribution of E. ockendeni genetic diversity across eastern Ecuador.

Anthropogenic hybridization in wildlife has been identified as one of the main causes of genetic homogenization, highlighting the need for identification and evaluation of populations at risk. Relocation of wildlife for game management purposes is a widespread practice that may promote the admixing of genetically different populations, subspecies or species. We undertook a large-scale study on the Iberian Peninsula to assess the extent of hybridization in red-legged partridge Alectoris rufa populations, which have been subject to extensive restocking of farm-reared individuals. Using a polymerase chain reaction-restriction fragment length polymorphism technique to assess the prevalence of individuals with mtDNA from other species, we examined samples of A. rufa from museum specimens (229), extant wild populations (955) and game farms (530). We found widespread occurrence of chukar partridge Alectoris chukar mtDNA lineages in samples obtained from game farm partridges (63% of game farms) and from wild partridges (45% of populations), but no allochthonous mtDNA lineages were found in museum partridges. We also found that the probability of occurrence and the number of partridges with allochthonous lineages was higher in localities where recent restocking had occurred. In addition, investigation of trends in bag records and the numbers of game farms over the past 30 years suggests that the general decline of wild populations has been accompanied by an increase in game farm facilities. These results suggest that supplemental stocking practices are threatening the integrity of the wild population gene pool. We recommend that rural development policies and associated wildlife management programs focused on maintaining high stock densities for hunting also need to consider the impact of game management on the genetic integrity of game populations.

Summary1. Sex differences in testosterone levels and sex-biased sensitivity to testosterone are the basis of some ideas postulated to account for sex-linked environmental vulnerability during early life. However, sex variation in circulating testosterone levels has been scarcely explored and never manipulated at post-natal stages of birds in the wild. 2. We measured and experimentally increased circulating testosterone levels in nestling Eurasian kestrels Falco tinnunculus . We investigated, possible sexual differences in testosterone levels and the effect of this hormone on growth (body mass and tarsus length) and cell-mediated immunity in males and females. We also explored testosterone effects on rump coloration, a highly variable melanin-based trait in male nestlings. We analysed data on circulating testosterone levels of nestlings in 15 additional bird species. 3. Increased levels of testosterone tended to negatively affect body condition, reduced cell-mediated immune responses in male and female nestlings and also diminished the expression of grey rump coloration in male nestlings. No sex differences were observed in testosterone levels in either control or increased testosterone group nestlings, and no interactions were found between sex and treatment. However, male nestlings showed a lower cell-mediated immune response than females in both groups. 4. Our results indicate first, that a high level of testosterone in all nestlings in a brood entails costs, at least in terms of immunity, coloration and probably growth. Secondly, sex differences in post-natal cell-mediated immunity, and consequently in the capacity to prevent diseases, cannot be explained by sex differences in circulating testosterone levels. Finally, by comparing published data at an interspecific level, contradictory sex patterns in circulating testosterone levels have been found, supporting the idea that circulating testosterone might not be a proximate factor causing sex-dependent vulnerability in bird species.