Despite prolonged association in closed populations,an intertidal predator does not prefer abundant local prey to novel prey

The diets of predators should reflect interactions between their behavioural and anatomical constraints and the availability and accessibility of prey, although feeding preferences may also reflect adaptation to locally abundant prey, particularly in closed populations. On the south‐east coast of Australia, the whelk Haustrum vinosum (Lamarck, 1822) and its prey communities provide a model system in which to test the effect of variation in prey availability on diet and dietary preferences. Haustrum vinosum is a direct developing species, forming effectively closed populations, with the potential for local adaptation at local and regional scales. Here we show that populations of whelks east and west of a biogeographical barrier encounter different prey assemblages, and have different feeding patterns and apparent prey preferences. We then use a prey choice experiment to test for evidence that H. vinosum from three populations west of the barrier display an inherent preference for its most frequently encountered western prey species, the mussel Brachidontes rostratus (Dunker, 1857), over a novel prey, the barnacle Tesseropora rosea (Krauss, 1848). We detected no prey preference within any population, suggesting past association with B. rostratus did not influence prey selection. Our data support the hypothesis that predators with limited dispersal and high population differentiation are able to maintain flexible generalist foraging patterns, even when they encounter novel prey. © 2013 The Linnean Society of London     

First captive breeding of the imperial parrot (Amazona imperialis)

We describe the rearing and development of the first imperial parrot (Amazona imperialis) hatched and raised in captivity. A single egg was hen-incubated for 28 days, and the chick was parent-fed for ～14 days, after which it was removed for hand-rearing. Similar to wild, parent-reared imperial nestlings, the chick developed fully within 12 weeks, weaning at 540 g body weight. Endangered and endemic to Dominica, the imperial is a vital flagship for oceanic rainforest conservation. Chronicling the neonatal development of A. imperialis helps illuminate the natural history of this enigmatic species, whose secretive nesting habits and low population density have frustrated a detailed understanding of its ecology and reproduction.     

Consequences of pre-dispersal damage by insects for the dispersal and recruitment of mangroves

Herbivores may enhance plant recruitment, but such positive interactions may be overlooked in favour of obvious negative effects of herbivory on propagules. My objective was to determine whether larval insects that feed and develop within fruit of the mangrove Avicennia marina act as mutualist herbivores by increasing the dispersal of propagules without affecting their viability and emerging successfully as adults following dispersal of the propagule by water. Surveys revealed that frugivory is common throughout the mangrove forest, and fruit had up to six exit holes where larvae had emerged as adults. Larval insects did not affect the flotation of propagules with pericarps, a thin structure that provides buoyancy for dispersal by water. In contrast, after simulating germination by removing the pericarp, the majority of propagules with three exit holes floated on average for 20 h longer than those without exit holes, which sank immediately. Based on this evidence that frugivory could increase the dispersal potential of propagules, I predicted that propagules consumed by larval insects should disperse farther than undamaged propagules, and this was tested by quantifying the potential viability of propagules stranded on beaches at increasing distances (up to 20 km) from mangrove forests. Flies and moths emerged as adults after being transported tens of kilometres within mangrove propagules, revealing a novel mode of dispersal. Proportionally fewer potentially viable propagules were supplied to beaches at increasing distances from mangrove forests, however, indicating that larval insects negatively affect recruitment and are thus not acting as mutualist herbivores. Nevertheless, when transported back to the mangrove forest, seedlings established from propagules damaged by larval insects and stranded on beaches. Therefore, although frugivory does not preclude mangrove recruitment, its negative effects in the pre-dispersal environment may be intensified with increasing dispersal distance, thus limiting the long-distance supply of propagules and recruitment of mangroves.     

<Emphasis Type="Italic">Pichia stipitis</Emphasis> xylose reductase helps detoxifying lignocellulosic hydrolysate by reducing 5-hydroxymethyl-furfural (HMF)

Background  

Pichia stipitis xylose reductase (Ps-XR) has been used to design Saccharomyces cerevisiae strains that are able to ferment xylose. One example is the industrial S. cerevisiae xylose-consuming strain TMB3400, which was constructed by expression of P. stipitis xylose reductase and xylitol dehydrogenase and overexpression of endogenous xylulose kinase in the industrial S. cerevisiae strain USM21.     

Reduced natural selection associated with low recombination in Drosophila melanogaster

Synonymous codons are not used equally in many organisms, and the extent of codon bias varies among loci. Earlier studies have suggested that more highly expressed loci in Drosophila melanogaster are more biased, consistent with findings from several prokaryotes and unicellular eukaryotes that codon bias is partly due to natural selection for translational efficiency. We link this model of varying selection intensity to the population-genetics prediction that the effectiveness of natural selection is decreased under reduced recombination. In analyses of 385 D. melanogaster loci, we find that codon bias is reduced in regions of low recombination (i.e., near centromeres and telomeres and on the fourth chromosome). The effect does not appear to be a linear function of recombination rate; rather, it seems limited to regions with the very lowest levels of recombination. The large majority of the genome apparently experiences recombination at a sufficiently high rate for effective natural selection against suboptimal codons. These findings support models of the Hill-Robertson effect and genetic hitchhiking and are largely consistent with multiple reports of low levels of DNA sequence variation in regions of low recombination.