1. Individual variation in the trade-off between self-maintenance and offspring quality was assessed in tree swallows, Tachycineta bicolor , by manipulating reproductive effort while simultaneously immunochallenging breeding females. 2. An experimental manipulation of parental effort was conducted by creating broods of, on average, three, five and eight nestlings. Breeding females were immunoch...

Please cite this article in press as: Lutermann grey mouse lemurs, Animal Behaviour (2010 Animals spend a substantial proportion of their lives resting and consequently the choice of a sleeping site can dramatically affect an individual's fitness. Sleeping sites have been implicated in predator defence and thermoregulation and their distribution can affect breeding and social systems in small m...

Background The genus Eucalyptus is the most important planted tree to the Brazilian economy. Besides being a source of timber, its wood pulp is mostly used for papermaking. There is a considerable interest in its genetic improvement due to the economic importance of the gender to forestry companies. The time required to obtain ideal populations, after selective breeding, is a limiting factor of...

Point Pelee National Park in southwestern Ontario, Canada--a major migratory route and vital breeding area for many birds--has localized areas of organochlorine (OC) contamination from the 1950s and 1960s. During 2002, we investigated the effect of tissue OC contaminant levels on the physiology and growth of nestling tree swallows (Tachycineta bicolor). Polychlorinated biphenyl (PCB) contaminat...

Maikop Experiment Station of VIR maintains and studies the richest genetic diversity primitive East Asian apple-tree species, including sections Docyniopsis C.C. Schneid. Sorbomalus Zabel. In addition, research covers species Gymnomeles Koehne section, more advanced in evolutionary development, which, addition to Siberia Far East, are also spread China, Mongolia other regions Asia. The collecti...

In anurans, circulating levels of androgens influence certain secondary sexual characteristics that are expressed only during the breeding season. We studied the contractile properties of external oblique muscles (used to power sound production) in a species of North American gray tree frog, Hyla chrysoscelis, during the breeding season and also in testosterone-treated captive males and females...

Rediscovered in the wild twenty years ago, the breeding biology of wild Blue-throated Macaws remains largely unexplored, yet is essential to its effective conservation and recovery. Here, we analyse reproductive parameters in an intensively managed wild population of Blue-throated Macaws, providing the first data on the breeding biology of this critically endangered species. During the six-year...

Conservation strategies are urgently needed in Tropical areas for widely used tree species. Increasing numbers of species are threatened by overexploitation and their recovery might be poor due to low reproductive success and poor regeneration rates. One of the first steps in developing any conservation policy should be an assessment of the reproductive biology of species that are threatened by...