Bird diversity patterns in Neotropical temperate farmlands: The role of environmental factors and trophic groups in the spring and autumn

Productivity, habitat heterogeneity and environmental similarity are of the most widely accepted hypotheses to explain spatial patterns of species richness and species composition similarity. Environmental factors may exhibit seasonal changes affecting species distributions. We explored possible changes in spatial patterns of bird species richness and species composition similarity. Feeding habits are likely to have a major influence in bird–environment associations and, given that food availability shows seasonal changes in temperate climates, we expect those associations to differ by trophic group (insectivores or granivores). We surveyed birds and estimated environmental variables along line‐transects covering an E‐W gradient of annual precipitation in the Pampas of Argentina during the autumn and the spring. We examined responses of bird species richness to spatial changes in habitat productivity and heterogeneity using regression analyses, and explored potential differences between seasons of those responses. Furthermore, we used Mantel tests to examine the relationship between species composition similarity and both the environmental similarity between sites and the geographic distance between sites, also assessing differences between seasons in those relationships. Richness of insectivorous birds was directly related to primary productivity in both seasons, whereas richness of seed‐eaters showed a positive association with habitat heterogeneity during the spring. Species composition similarity between assemblages was correlated with both productivity similarity and geographic proximity during the autumn and the spring, except for insectivore assemblages. Diversity within main trophic groups seemed to reflect differences in their spatial patterns as a response to changes between seasons in the spatial patterns of food resources. Our findings suggest that considering different seasons and functional groups in the analyses of diversity spatial pattern could contribute to better understand the determinants of biological diversity in temperate climates.     

Cytogenetic and molecular characterization of morphologically variable Sisyrinchium micranthum (Iridaceae) in southern Brazil

Sisyrinchium micranthum is native to southern Brazil and shows a wide range of morphological variation in this region. This study was performed to compare individuals of this species in terms of traits such as morphology, chromosome number, meiotic behaviour, pollen viability and genetic diversity using inter simple sequence repeat markers. First, general morphological aspects were evaluated and plants were classified into three morphological categories (CI, CII and CIII) to analyse the cytogenetic and genetic data. Three chromosome numbers corresponding to three ploidies were found: 2n = 2x = 16, 2n = 4x = 32 and 2n = 6x = 48. All morphological types showed regular meiotic behaviour and high meiotic index values and pollen viability. CII is the most frequent in southern Brazil. The most common haploid chromosome number, n = 8, has not been reported previously in this species. The percentage of polymorphic loci ranged from 6.45 to 61.29% for each accession. Molecular and cytogenetic analyses indicate that some S. micranthum accessions may have more than one ploidy. This study represents the first effort to characterize this taxonomically complex species based on cytogenetic and genetic aspects. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169 , 350–364.     

Inbreeding depression in Vriesea gigantea,a perennial bromeliad from southern Brazil

Inbreeding depression is a reduction of fitness in the progeny of closely related individuals and its effects are assigned to selfing or biparental inbreeding. Vriesea gigantea is a self‐compatible bromeliad species distributed in the Brazilian Atlantic rainforest and habitat destruction and fragmentation and collection have decreased the natural populations. We aim to describe the occurrence of inbreeding depression (δ) in three natural populations of V. gigantea and to correlate this phenomenon with previous studies of fertility, genetic diversity, population genetic structure, gene flow, mating system and seed dispersal in this species. Fifty‐four adult plants were sampled and 108 flowers were used for pollination treatments (selfing, outcrossing and control). For adult plants, we analysed plant and inflorescence height, flower numbers and seed set. In the progenies, evaluated parameters included seed germination and seedling survival rate. The results indicated low to moderate levels of inbreeding depression in V. gigantea (δ = 0.02 to 0.39), in agreement with molecular data from a previous study. Vriesea gigantea populations tolerate some degree of inbreeding, which is consistent with previous results on fertility, mating system, genetic diversity and gene flow. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169 , 312–319.     

Phylogenetic analysis of Micrathena and Chaetacis spiders (Araneae: Araneidae) reveals multiple origins of extreme sexual size dimorphism and long abdominal spines

The phylogenetic relationships amongst the New World spiny orb‐weaving spiders Micrathena and Chaetacis were assessed through parsimony and Bayesian analyses of morphological characters. A total of 146 characters was scored for ten outgroup taxa and 37 Micrathena and four Chaetacis species. The results indicate that Chaetacis nests within Micrathena and we propose Chaetacis as a junior synonym of Micrathena. Twelve subgeneric species groups of Micrathena are recognized and diagnosed. Species with extremely long spines evolved at least eight times in the genus and we suggest that this may be related to antipredator defences. Micrathena is primitively sexually monomorphic and extreme sexual size dimorphism has arisen at least six times in the genus. Most of these events are because of enlargement of the female in relation to the ancestral size, although in two cases sexual dimorphism was attained through male reduction, adding more data to the ‘giant females’ vs. ‘dwarf males’ controversy. The genus is probably of South American origin and has repeatedly invaded Central and North America. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 14–53.     

Permian bryophytes of Western Gondwanaland from the Paraná Basin in Brazil

Abstract: This study involves bryophyte fossils from the Teresina Formation (Permian–Guadalupian) collected in the Rio Preto Quarry in the state of Paraná, southern Brazil. Two new genera are proposed, with two new species: Capimirinus riopretensis sp. nov. and Yguajemanus yucapirus sp. nov. C. riopretensis sp. nov. included a lateral sporophyte that was organically attached to a gametophyte and is thus one of the oldest pleurocarpous fossils known today. This discovery provides clear evidence of the evolution of mosses during the Permian, because an acrocarpous moss from this period was also found in India. The preservation of such a fragile structure demonstrates that no prefossilization displacement took place and that the sediments accumulated in a low‐energy, fresh‐water environment, similar to a lake fed by rain, and isolated from the direct influence of the sea. Campimirinus riopretensis may be placed within the earlier pleurocarps, and Yguajemanus yucapirus sp. nov. may belong to the Bryalean families. However, we were not able to place neither of these species in any existing family today.     

Effects of hydration conditions on the stroma inclusion of some CAM chloroplasts

Abstract The tubular protein inclusion of the chloroplasts of some CAM plants was found to maintain its normal pattern of accumulating by day and dissolving at night when the hydration state of the chloroplasts was reversed by promoting influx of water during the day and efflux of water during the night. Morphometric study of the chloroplast inclusion of Sedum telephium supports our suggestion that the behaviour of the aggregate of tubules is independent of the water content of the chloroplasts.     

Differential protein expression in the midgut of Culex quinquefasciatus mosquitoes induced by the insecticide temephos

Mosquitoes are vectors for pathogens of malaria, lymphatic filariasis, dengue, chikungunya, yellow fever and Japanese encephalitis. Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) is a known vector of lymphatic filariasis. Its control in Brazil has been managed using the organophosphate temephos. Studies examining the proteins of Cx. quinquefasciatus that are differentially expressed in response to temephos further understanding of the modes of action of the insecticide and may potentially identify resistance factors in the mosquito. In the present study, a comparative proteomic analysis, using 2‐dimensional electrophoresis coupled with matrix‐assisted laser desorption/ionization (MALDI) time of flight (TOF)/TOF mass spectrometry, and bioinformatics analyses were performed to identify midgut proteins in Cx. quinquefasciatus larvae that were differentially expressed in response to exposure to temephos relative to those in untreated controls. A total of 91 protein spots were differentially expressed; 40 were upregulated and 51 were downregulated by temephos. A total of 22 proteins, predominantly upregulated, were identified as known to play a role in the immune response, whereas the downregulated proteins were involved in energy and protein catabolism. This is the first proteome study of the midgut of Cx. quinquefasciatus and it provides insights into the molecular mechanisms of insecticide‐induced responses in the mosquito.     

Life history and production of Agapetus quadratus (Trichoptera: Glossosomatidae) in a temporary, spring-fed stream

1. The life history and trophic basis of production of the caddisfly grazer Agapetus quadratus were studied in the torrent Gorg Blau, a spring‐fed stream on the island of Majorca that dries annually during summer. 2. Quantitative random samples were taken every 2–3 weeks during an annual surficial flow period, from November 2000 to mid‐July 2001. Instars of field‐collected larvae were determined by measurements of head width and pronotum length, and the sex of all pupae was determined to study sexual dimorphism and sex ratio. 3. Stage‐frequency histograms suggested a trivoltine population, with an average cohort time of 4 months. Larval development was asynchronous, with continuous growth and overlapping generations. Recruitment peaks were identified in mid‐November, early March and late June, indicative of winter, spring and summer generations. On average, females were larger than males and the mean sex ratio was 2 : 3 (females : males). Population densities and biomasses derived from the field data were used to calculate production and turnover rate. 4. Annual production of A. quadratus in the torrent Gorg Blau (4.80 g dry mass m^?2 year^?1) was the highest ever reported for the genus, being comparable with that estimated for some insects with rapid development and multiple cohorts. 5. Estimates of production of A. quadratus were combined with foregut content analysis to estimate the fraction of total production derived from the principal food sources: algae and organic detritus. Algae supported a major proportion of the production of this grazer. 6. The low density of predators characteristic of many temporary streams, and the small amplitudes in discharge and temperature during most of the wet period that characterise the spring habitats might allow high levels of grazer production in this particular Mediterranean stream.