Nutrients in fruits as determinants of resource tracking by birds

Fruit pulp is an important source of nutrients for many bird species. Fruit-eating birds use a variety of strategies to cope with changes in the availability of fruits, exhibiting a remarkable ability to track resources. We assessed the role of nutrient availability in the fruiting environment as a factor driving resource tracking by fruit-eating birds. Fruit consumptionby the four most common frugivorous species in a 6-ha plot in the Southern Yungas montane forest of Argentina was assessed. We determined the content of selected nutrients (soluble carbohydrates, proteins, phenols, ascorbic acid and essential minerals) in 22 fruiting plant species eaten by birds, and measured fruit-frugivore interactions and the availability of nutrients and dry fruit pulp mass over 2 years. There was strong temporal covariation in the availability of the selected nutrients in fruits across the study period. Similarly, the availability of nutrients in the fruiting environment co-varied with pulp mass. Fruit consumption by the four commonest bird species and theabundance of most species were positively associated with nutrient availability and dry pulp mass. Nutrient availability was a good predictor of temporal fruit tracking by three of the four commonest frugivores. Despite large differences in particular nutrient concentrations in fruits, overall nutrient (and pulp) quantity in the fruiting environment played a greater role in fruit tracking than did the nutritional quality of individual fruits.While overall nutrient availability (i.e. across fruit) and total pulp mass were important determinants of fruit tracking, we suggest that plant species-specific differences in fruit nutrient concentration may be important in short-term foraging decisions involved in fruit choice and nutritional balance of birds.Fil: Blendinger, Pedro Gerardo. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Giannini, Norberto Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Zampini, Iris Catiana. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; ArgentinaFil: Ordóñez, Roxana Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Torres, Sebastián. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; ArgentinaFil: Sayago, Jorge E.. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales E Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; ArgentinaFil: Ruggera, Román Alberto. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Isla, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentin

Comparison between <i>A</i>. <i>fraterculus (A</i>. <i>f)</i> and <i>A</i>. <i>ludens (A</i>. <i>l)</i> polytene chromosome maps.

<p>Lines connecting the chromosomes indicate sections with similar banding pattern and horizontal arrows show the relative orientation between them. C indicates the centromere. Asterisks indicate the transposition of a specific region between the two species.</p

Estimating functions for repeated measures with incidental parameters

Estimating functions, Incidental parameters, Neyman–Scott problem, Repeated measures, Structural parameters,