Bacterial degradability of an intrafeather unmelanized ornament: a role for feather‐degrading bacteria in sexual selection?

The impact of feather‐degrading bacilli on feathers depends on the presence or absence of melanin. In vitro studies have demonstrated that unmelanized (white) feathers are more degradable by bacteria than melanized (dark) ones. However, no previous study has looked at the possible effect of feather‐degrading bacilli on the occurrence of patterns of unmelanized patches on otherwise melanized feathers. The pied flycatcher Ficedula hypoleuca Pallas, 1764 is a sexually dimorphic passerine with white wing bands consisting of unmelanized patches on dark flight feathers. These patches are considered to be a sexually selected trait in Ficedula flycatchers, especially in males, where the patches are more conspicuous (larger and possibly whiter) than in females. Using in vitro tests of feather bacterial degradation, we compared the degradability of unmelanized and melanized areas of the same feather for 127 primaries collected from the same number of individuals in a population breeding in central Spain (58 males and 69 females). In addition, we also looked for sex differences in feather degradability. Based on honest signalling theory and on the fact that there is stronger sexual selection for males to signal feather quality than in females, we predicted that unmelanized areas should be more degradable by bacteria than melanized ones within the same feather, and that these unmelanized areas should also be more degradable in males than in females. We confirmed both predictions. Microstructural differences between cross‐section dimensions of unmelanized and melanized barbs, but not differences in the density of barbs within unmelanized and melanized areas of feathers in males and females, could partly explain differences in degradability. This is the first study to show differences in bacterial degradability among markings on the same feather and among unmelanized feather patches between males and females as predicted by sexual selection theory. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 409–419.     

Damage caused by mistletoe Misodendrum punctulatum Banks Ex Dc. on architecture and radial growth of Nothofagus pumilio (Poepp. et Endl.) Krasser forests of southern Chile

Parasitic plants rely completely or partially on host plant, namely holoparasitic or hemiparasitic, respectively. The effect of parasitism on host plants is not fully known. Misodendrum punctulatum (Misodendraceae) is the most common hemiparasite species in the southernmost forests of Chile and Argentina, and it has been identified as an important sanitary problem in forestry. In this study we evaluated the M. punctulatum effect on growth rates and architecture of pure Nothofagus pumilio (Nothofagaceae) forests in southern South America (52°10′S; 71°55′W). We established three plots of 30 × 30 m, and 10 cores were extracted from diameter at breast height (d.b.h. = 1.3 m) from living trees in each plot, using increment borers. Tree rings were measured, and anova was used to compare the annual growth rate of both infected and uninfected N. pumilio. The results showed that N. pumilio trees severely infected by M. punctulatum reduce growth rates in contrast with uninfected individuals (P < 0.05). Besides, trees with high‐infection levels evidenced deterioration in its architecture, showing asymmetric and suppressed canopies, according to ad hoc numerical indexes. This study provides a starting point to understand the parasite–host relationship in the Patagonian forests of southern Chile.     

The genus Huperzia (Lycopodiaceae) in the Azores and Madeira

The taxonomy and nomenclature of the genus Huperzia Bernh. in the Azores and Madeira have been reviewed. Plants collected in the Azores and Madeira were characterized morphologically. The independence between two endemic species common to Madeira and the Azores Islands –Huperzia suberecta (Lowe) Tardieu and Huperzia dentata (Herter) Holub – is clearly shown. A clear‐cut morphological separation between these taxa and Huperzia selago (L.) Bernh. ex Schrank & Mart. of continental Europe is established. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 522–533.     

Molecular phylogeny and diversification history of Prosopis (Fabaceae: Mimosoideae)

The genus Prosopis is an important member of arid and semiarid environments around the world. To study Prosopis diversification and evolution, a combined approach including molecular phylogeny, molecular dating, and character optimization analysis was applied. Phylogenetic relationships were inferred from five different molecular markers ( mat K- trn K, trn L- trn F, trn S- psb C, G3pdh, NIA). Taxon sampling involved a total of 30 Prosopis species that represented all Sections and Series and the complete geographical range of the genus. The results suggest that Prosopis is not a natural group. Molecular dating analysis indicates that the divergence between Section Strombocarpa and Section Algarobia plus Section Monilicarpa occurred in the Oligocene, contrasting with a much recent diversification (Late Miocene) within each of these groups. The diversification of the group formed by species of Series Chilenses, Pallidae, and Ruscifoliae is inferred to have started in the Pliocene, showing a high diversification rate. The moment of diversification within the major lineages of American species of Prosopis is coincident with the spreading of arid areas in the Americas, suggesting a climatic control for diversification of the group. Optimization of habitat parameters suggests an ancient occupation of arid environments by Prosopis species.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 621–640.     

Suicidal process,suicidal communication and psychosocial situation of young suicide attempters in a rural Vietnamese community

The study aimed to explore the suicidal process, suicidal communication and psychosocial situation of young suicide attempters in a rural community in Hanoi, Vietnam. Semi-structured interviews were conducted, in a community setting, with 19 suicide attempters aged 15-24 who had been consecutively hospitalized in an intensive care unit. In 12 of 19 cases, the first pressing, distinct and constant suicidal thoughts appeared less than one day before the suicide attempt in question. However, distress and mild, fleeting suicidal thoughts had been present up to six months before the suicide attempt in 16 cases. Five respondents had a suicide plan one to three days before attempting suicide. Altogether, 13 engaged in some form of suicidal communication before their attempt. This communication was, however, difficult for outsiders to interpret. Twelve of the respondents were victims of regular physical abuse and 16 had suffered psychological violence for at least one year before attempting suicide. Eighteen of the respondents used pesticides or raticides in their suicide attempts. None sought advice or consultation in the community despite long-standing psychosocial problems. The strategy of reducing the availability of suicide means (e.g., pesticides or raticides) in Asian countries should be complemented with a long-term suicide-preventive strategy that targets school dropouts and domestic violence, and promotes coping abilities and communication about psychological and social problems as well as recognition of signs of distress and suicidal communication.     

Linking plant functional traits with post‐fire sprouting vigour in woody species in central Argentina

Abstract Sprouting vigour is determined by the plant amount of reserves and intrinsic growth rate of plants. While the first factor has been well studied, the second is far less understood. Although a higher growth rate would imply a higher sprouting vigour, fast‐growing species may have less below‐ground reserves, and thus, a lower sprouting potential. The relative importance of both opposite effects was little explored in the literature. To analyse the influence of growth rate on sprouting vigour, one growth season after a fire we measured plant height of the old (pre‐fire) and new (post‐fire) tissue in 194 individuals of 14 woody species from a woodland in central Argentina. We calculated a mean value of pre‐ and post‐fire height for each species, and obtained from a data‐base potential height at maturity, wood density (WD) and specific leaf area (SLA), as surrogates of intrinsic growth rate. We performed a forward stepwise multiple regression using WD and SLA, together with mean pre‐fire height or potential height as independent variables, and mean post‐fire height (as an indicator of resprout vigour) as the dependent variable. Interactions were also tested. Pre‐fire height, WD and their interaction term were the variables that best explained post‐fire height. We also analysed the relationship between pre‐ and post‐fire size for each species independently by fitting hyperbolic functions. Then we correlated both parameters of the functions to species characteristics (WD, SLA, potential height and mean pre‐fire height). Both parameters of the hyperbolic functions were significantly correlated only with WD, but not with the other species characteristics. All results together indicate that species with low WD (i.e. high potential growth rate) regrow more vigorously than species with high WD when pre‐fire individuals were tall. In contrast, when pre‐fire individuals were small, WD had no influence on sprout vigour. A trade‐off between allocation of biomass to underground reserves and shoot growth seems to be responsible for the patterns obtained. For small individuals, below‐ground reserves seem to play a more important role than inherent growth rate (here measured through WD) in determining the sprouting vigour, while for large individuals, growth rate seems more important than reserves.     

Palaeoecological significance of Barremian ammonite assemblages and facies variations from Southwest Mexico

Analyses of ammonite shell forms of two Barremian stratigraphic sections from Southwest Mexico consist of two well-defined morphotypes: (1) Small uncoiled, mostly leptoceratoid ancyloconic shells of the families Ancyloceratidae and Hamulinidae, and (2) middle-sized involute to moderately evolute oxycone to discocone shells of the family Pulchelliidae. Index taxa allow the recognition of standard ammonite biozones for the Barremian, which permit the relative dating of different processes that occurred through the water column in the environment of deposition. The vertical distribution of ammonite morphotypes and facies suggests changes of the palaeoceanographic and sedimentological conditions that prevailed in the area during Barremian time. Petrologic data, analyses of the organic carbon and carbonate contents of the rocks support the idea that oxygen-deficient bottom waters existed within a shallow marine, tectonically active area with little carbonate deposition during the early early Barremian (upper part of the Taveraidiscus hugii Zone through the base of the Nicklesia pulchella Zone). These conditions in the basin caused a proliferation of middle-water depth ammonites of Morphotype 1 but prevented the abundance of nektobenthic forms of Morphotype 2. Oxic conditions on a more calcareous and open normal marine environment seem to have been reestablished progressively during a transgressive episode from late early-early late Barremian (upper part of the Nicklesia pulchella Zone through the Gerhardtia sartousiana Zone). This environmental setting supported more facies dependent nektobenthic ammonites of Morphotype 2 to flourish within the basin.     

Reproductive ecology of Rhododendron ponticum (Ericaceae) in relict Mediterranean populations

In the southern Iberian Peninsula, Rhododendron ponticum occurs in restricted and vulnerable populations as a Tertiary relict. Population structure and the main phases of the reproductive process were examined in order to shed light on recruitment patterns and limitations. Rhododendron ponticum flowers are self-compatible and attract a diverse array of insects, which are responsible for a considerable number of seeds set in the populations. Nevertheless, only adults form populations, whilst seedlings are scarce and saplings virtually absent (only two juveniles out of 2489 adults sampled). Non-specialized vegetative multiplication by layering was observed. Recruitment failure seems to depend on the scarcity of safe microsites, which are free from drought, for seedling establishment. The observations contrast with R. ponticum 's reputation as an aggressive invader in temperate Atlantic areas. It is proposed that the species shows a variable balance between sexual reproduction and vegetative multiplication depending on environmental conditions. At present, only the latter seems to be prevailing in relict populations in the Iberian Peninsula. This flexible reproductive strategy is also discussed as a mechanism allowing persistence during geological climatic oscillations.  © The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 297–311.     

Mexical plant phenology: is it similar to Mediterranean communities?

The sclerophyllous, evergreen vegetation found in Mexico under tropical climate is named 'Mexical' (MEX) and presents many traits that have been thought to converge under a Mediterranean climate. Flowering phenology is strongly similar across Mediterranean-type ecosystems (MTEs) and this paper investigates MEX plant phenology in this context. The common history of the vegetation and the differences in the climatic conditions experienced by MEX and MTE taxa provide an ideal scenario to infer the relative importance of natural selection and historical constraints in the phenological response of plants to climatic conditions. This study has involved collecting field and bibliographic data on flowering phenology of MEX communities to detect (1) similarities at the community level between MTEs and MEX, (2) similarities between Tertiary and Quaternary taxa in MTEs and MEX, and (3) similarities between congeneric taxa from MEX and MTEs (taxa sharing a common ancestor but having evolved under different climates). Flowering in MEX does not occur mainly in spring, as in MTEs, but in summer, suggesting a response that maximizes water use in the rainy season. Flowering phenology of MEX species differed from their MTE congeneric species, suggesting that even though a common ancestor is shared, environmental pressures have led to different phenological responses in MEX and MTE plants. The flowering season for species that originated in the Tertiary and Quaternary did not differ in MEX, as expected, because of climatic uniformity along the whole time line. In MTEs, flowering differences between Tertiary and Quaternary species were not congruent, suggesting that the balance between the historical constraints and the selective force of the Mediterranean climate is different among the three MTEs, and a particular explanation is needed for each. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 297–303.