Morphology and genetics reveal an intriguing pattern of differentiation at a very small geographic scale in a bird species, the forest thrush Turdus lherminieri.

Mobile organisms are expected to show population differentiation only over fairly large geographical distances. However, there is growing evidence of discrepancy between dispersal potential and realized gene flow. Here we report an intriguing pattern of differentiation at a very small spatial scale in the forest thrush (Turdus lherminieri), a bird species endemic to the Lesser Antilles. Analysis of 331 individuals from 17 sampling sites distributed over three islands revealed a clear morphological and genetic differentiation between these islands isolated by 40-50 km. More surprisingly, we found that the phenotypic divergence between the two geographic zones of the island of Guadeloupe was associated with a very strong genetic differentiation (Fst from 0.073-0.153), making this pattern a remarkable case in birds given the very small spatial scale considered. Molecular data (mitochondrial control region sequences and microsatellite genotypes) suggest that this strong differentiation could have occurred in situ, although alternative hypotheses cannot be fully discarded. This study suggests that the ongoing habitat fragmentation, especially in tropical forests, may have a deeper impact than previously thought on avian populations.

Permanent genetic resources added to Molecular Ecology Resources Database 1 December 2011-31 January 2012.

This article documents the addition of 473 microsatellite marker loci and 71 pairs of single-nucleotide polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Barteria fistulosa, Bombus morio, Galaxias platei, Hematodinium perezi, Macrocentrus cingulum Brischke (a.k.a. M. abdominalis Fab., M. grandii Goidanich or M. gifuensis Ashmead), Micropogonias furnieri, Nerita melanotragus, Nilaparvata lugens Stål, Sciaenops ocellatus, Scomber scombrus, Spodoptera frugiperda and Turdus lherminieri. These loci were cross-tested on the following species: Barteria dewevrei, Barteria nigritana, Barteria solida, Cynoscion acoupa, Cynoscion jamaicensis, Cynoscion leiarchus, Cynoscion nebulosus, Cynoscion striatus, Cynoscion virescens, Macrodon ancylodon, Menticirrhus americanus, Nilaparvata muiri and Umbrina canosai. This article also documents the addition of 116 sequencing primer pairs for Dicentrarchus labrax.

Maternal investment of female mallards is influenced by male carotenoid-based coloration.

The differential allocation hypothesis predicts that females modify their investment in a breeding attempt according to its reproductive value. One prediction of this hypothesis is that females will increase reproductive investment when mated to high-quality males. In birds, it was shown that females can modulate pre-hatch reproductive investment by manipulating egg and clutch sizes and/or the concentrations of egg internal compounds according to paternal attractiveness. However, the differential allocation of immune factors has seldom been considered, particularly with an experimental approach. The carotenoid-based ornaments can function as reliable signals of quality, indicating better immunity or ability to resist parasites. Thus, numerous studies show that females use the expression of carotenoid-based colour when choosing mates; but the influence of this paternal coloration on maternal investment decisions has seldom been considered and has only been experimentally studied with artificial manipulation of male coloration. Here, we used dietary carotenoid provisioning to manipulate male mallard (Anas platyrhynchos) bill coloration, a sexually selected trait, and followed female investment. We show that an increase of male bill coloration positively influenced egg mass and albumen lysozyme concentration. By contrast, yolk carotenoid concentration was not affected by paternal ornamentation. Maternal decisions highlighted in this study may influence chick survival and compel males to maintain carotenoid-based coloration from the mate-choice period until egg-laying has been finished.