A new species of shrike (Laniidae: Laniarius) from Somalia, verified by DNA sequence data from the only known individual

A new species of bush-shrike is described on the basis of the only known individual. The bird was captured in a disturbed Acacia thicket near the town of Bulo Burti by the Shabeelle River in central Somalia. Believed to represent a species near extinction, the bird was kept alive, studied in captivity and then released. The type material comprises moulted feathers, blood samples and DNA extracted from feather quills. For comparison, DNA from other bush-shrikes was obtained from old museum skins and three live birds. Comparisons of base sequences from the cyt-b gene of mitochondrial DNA support the judgement that the bird represents a full species and is not a colour morph or hybrid of examined taxa. This procedure confirms that, in situations where collecting is not desirable, tissue from live individuals can be used to define taxa, and for comparisons with DNA from museum specimens of other taxa.     

A seasonal census of phenolics, fibre and alkaloids in foliage of forest trees in Costa Rica: some factors influencing their distribution and relation to host selection by Sphingidae and Saturniidae

The foliage of 80 species common in the Santa Rosa National Park, Costa Rica, has been analysed for content of total phenolics, condensed tannins, acid detergent fibre and water. Wherever possible analyses were performed at three stages in the life cycle of the leaf: young but fully expanded (coinciding with the beginning of the rainy season); middle-aged (two months later); and old (six months later). A comparison of the three age classes showed no significant change in the levels of phenolics or fibre as leaves aged but water content decreased significantly. A comparison of deciduous and evergreen species in the sample showed that the latter group had leaves with a significantly higher fibre content at all three sampling times, most particularly at the beginning of the rainy season, but other measures were not significantly different. Alkaloids were much more common in the foliage of deciduous species and it was observed that their distribution differed significantly from that of total phenolics and condensed tannins. It is suggested that the interaction that occurs between many tannins and alkaloids would be liable to reduce the defence capability of both classes of compounds if they occurred together.
High levels of defoliation occur in the early rainy season (third to tenth weeks) due to larvae of moths of the Sphingidae and Saturniidae. A comparison of investigated tree species that host larvae of these two taxa shows a striking dichotomy. Species that are selected by Sphingidae tend to be relatively deficient in levels of phenolics but are more likely to contain alkaloids, and probably other small toxic molecules. Saturniidae, on the other hand, appear to prefer host-species rich in phenolics but poor in alkaloids.     

Mechanism of Senescence Induction by Silicone Oil

The physiological basis for senescence symptoms induced by spraying attached primary leaves of bean plant (Phaseolus vulgaris L. cv. Brittlewax) with silicone oil emulsions was investigated. It was found that chlorophyll levels declined significantly between 24 and 48 h after spraying, whereas neither protein levels nor respiration rates were affected over a 7-day period. Rates of photosynthesis and reducing sugar levels in silicone-sprayed leaves were however significantly reduced after 1 and 24 h respectively. These responses were obtained using plants grown under low stress controlled environment conditions. By contrast, leaves on greenhouse plants did not senesce in response to silicone sprays. A possible mechanism of silicone oil action based on selective leaf penetration and inhibition of photosynthesis is postulated.     

Genetic Analysis in Wood-Decaying Fungi I. Genetic Variation and Evidence for Allopatric Speciation in Pleurotus ostreatus using Phenoloxidase Zymograms and Morphological Criteria

Using electropherograms (zymograms) of the phenoloxidase laccase and characteristics of mycelial growth and fruit body production, a distinct morphological and biochemical differentiation of two geographically isolated (allopatric) populations of the wood-rotting basidiomycete Pleurotus ostreatus became evident. No limitation in their outbreeding ability was observed, however. A specific secretory mechanism for an extracellular laccase, genetically different in the two geographical races, could be detected. An approximately 1: 1 segregation of this laccase band in the F₁ generation indicates that specific secretion of this enzyme is controlled by one gene only, Different degrees of genetic variation as shown by differences in the respective laccase spectra were found in the two geographical races. Only one enzyme band out of nine multiple laccases was found to be specific for fruit bodies. The value of zymograms for chemotaxonomic purposes, for the understanding of microevolution and for determination of genetic variation in fungi is critically discussed.     

The role of Greater Yellow-headed Vultures Cathartes melambrotus as scavengers in neotropical forest

The scavenging activities of Greater Yellow-headed Vultures Cathartes melambrotus were studied in the Amacayacu National Park, Colombia. This species is the most abundant vulture in the area and is usually the first species to locate a carcass, both in open clearings and inside the forest. The birds use olfaction to locate food. Vultures located 63% of provided carcasses, while mammalian scavengers found only 5%. Greater Yellow-headed Vultures were displaced when feeding by both Turkey Vultures Cathartes aura and King Vultures Sarcorhamphus papa .     

Assessment of the Sustainability of Wolverine Harvest in British Columbia,Canada

ABSTRACT Wolverines (Gulo gulo) are distributed across much of northern and western Canada and Alaska, USA, and they extend south into the mountainous western United States. Wolverines occur in most regions of British Columbia, Canada, with the highest population densities occurring in the interior mountainous areas. Wolverine populations in British Columbia have been primarily managed to provide a sustainable harvest for trappers and hunters. We used spatially based population estimates, population vital rate data, and spatially based harvest data to evaluate the sustainability of wolverine harvest (trapping and hunting) from 1985 to 2004. The median annual provincial wolverine harvest from 1985 to 2004 was 172 wolverines per year ( = 174.8), which was less than the median simulated estimate of provincial recruitment (195.9 wolverines/yr; = 209.7). Harvests in individual population units ranged from 0 to 280 over the 20-year period. Spatially, wolverine harvest was likely to have been unsustainable in 15 of the 71 population units with wolverines, and it was likely to have been sustainable in the remaining population units. Harvest in 5 of the other 56 population units was marginally sustainable and thus of potential management concern. To improve harvest management of wolverines in British Columbia, wildlife managers should focus on improved data collection and monitoring at a provincial scale, and they should work with trappers and hunters at regional scales to address issues specific to individual population units. Further research is required to improve the reliability of wolverine vital rate and population data.     

Interaction between chemical and tactile cues in mayfly detection of stoneflies

• 1 Sediments and eleven species of rooted submerged aquatic macrophytes were sampled from twenty-five lakes in southern Quebec to examine species patterns in metal content.
• 2 Linear regression models relating the content of metals in the macrophytes to their sediments demonstrated that the isoetoid (Eleocharis acicitlaris, Eriacaulon septangulare, Isoetes sp. and Sagittaria graminae) and the non-isoetoid species had different plant-sediment relationships. Canopy-forming (Myriophyllum spicatum, Potamogeton amplifalius, P. crispus and P. perfoliatus) and understory species (Elodea canadensis, P. robbinsii and Vallisneria americana) had similar linear regression model slopes, but the understory species had significantly higher intercepts, indicating higher plant metal contents for a given sediment metal concentration.
• 3 We grouped species by their biomass density (biomass (kg)/height (m)), a measure of the packing of the plant canopy, and averaged values for each metal, thereby producing one model per group. Comparison of the models by analysis of covariance revealed no significant differences in metal content. However, the canopy-forming species that occurred in monospecific and mixed species stands (M. spicatum and P. amplifolius) had significantly higher metal content for a given sediment metal content when an understory was present.
• 4 These results show that sediment metal content explains the largest proportion of variation in plant metal content across all sites and species. Deviations from what would be predicted by the most general model are not related to large-scale differences in sediment geochemistry, but to the physical structure of the weedbed within geochemically similar sediments.

     

How many SNPs are enough?

Since the days of allozyme analysis, we have been enamored with the idea that if we just had enough polymorphic mendelian loci, we could gauge the inbreeding level of individuals by measuring heterozygosity and simultaneously measure the degree of genetic relatedness between pairs of individuals. Given Mendel’s Laws, we have always known that we would need numerous independently segregating loci to achieve any reasonable degree of accuracy. Santure et al. (2010, this issue) use a 771 marker SNP panel to assess heterozygosity levels and to assess pairwise relatedness, and compare both with theoretical expectations obtained from a carefully recorded pedigree of a zebra finch breeding colony, as a function of increasing numbers of SNP markers. They also compare the SNP results with those from a 20‐locus microsatellite panel, showing that adding SNPs to a fairly large microsatellite panel improves accuracy, but given an existing panel of 125 SNPs, little is to be gained by adding microsatellites. They show that the accuracy available for estimating individual levels of inbreeding is somewhat limited. They also show that the average pairwise relatedness measures bracket pedigree relationship very nicely, but the variances for individual pairs remain substantial, even with a very large panel.     

Experimental and phylogenetic evidence for floral mimicry in a guild of fly-pollinated plants

Mimicry, as an adaptive explanation for the resemblance between organisms, is not always readily distinguishable from, inter alia , coincidence, shared ancestry, or convergent evolution. We tested the hypothesis that two rare South African orchid taxa Brownleea galpinii ssp. major (nectar-producing) and Disa cephalotes ssp. cephalotes (non-rewarding) are mimics of the nectar-producing flowers of a relatively common species, Scabiosa columbaria (Dipsacaceae), with which they always occur sympatrically. Flowers of the orchids were apparently unscented and had similar dimensions and almost identical spectral reflectance to the flowers of Scabiosa . The orchids were pollinated exclusively by long-proboscid flies (Tabanidae and Nemestrinidae) that feed mainly on nectar in Scabiosa flowers. Choice experiments showed that these flies did not discriminate between the orchids and Scabiosa when alighting on their flat-topped inflorescences. However, flies were not attracted to related orchids dissimilar to Scabiosa , or to inflorescences of B. galpinii that had been artificially reconstructed in the shape of a spike, rather than a flat-topped capitulum. A phylogenetic analysis showed traits that give the orchids a resemblance to Scabiosa , such as a flat-topped inflorescence and cream floral colouration with dark spots and short spurs, to be mostly apomorphic features, and therefore likely to be relatively recent adaptations for mimicry. We caution that the term mimic should not be applied to species whose resemblance to another species is due entirely to plesiomorphic traits that, in all likelihood, evolved prior to the ecological association.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 80 , 289–304.