Effects of glyphosate herbicide on soil and litter macro-arthropods in rainforest: Implications for forest restoration

Summary    Ecological restoration activities, including reforestation, often involve the use of herbicides for the removal of weedy plant cover. Little is known, however, about the effects of herbicides on assemblages of non-target organisms that colonize restored patches. We describe a field experiment to investigate effects of glyphosate herbicide (Roundup® Biactive™) on rainforest-associated soil- and litter-dwelling macro-arthropods. Our experimental protocol differed in two ways from other ecotoxicological studies of herbicides. First, we applied herbicide at a rate considerably greater than the manufacturer's recommended maximum in order to simulate worst-case scenarios that may occur in the practice of forest restoration. Second, our field experiment was carried out under dense canopy cover with sparse understorey vegetation, so that indirect impacts caused by the loss of existing vegetation were eliminated. Paired herbicide-treated and control plots were created within five rainforest remnants on the Maleny plateau of subtropical eastern Australia. Macro-arthropods were collected using litter extraction before, approximately 3 days after, and 3 months after herbicide application. Responses of arthropods were analysed at two levels of taxonomic resolution: 'coarse' arthropods (arthropods sorted to Order/Class), and ant species. Our results suggest that the use of glyphosate herbicide formulated as Roundup® Biactive™ is suitable for the control of unwanted plants in rainforest restoration sites as it appears to have minimal impact on assemblages of soil and litter macro-arthropods or at least those typical of intact rainforest.     

The insect assemblage in water filled tree-holes in a European temperate deciduous forest: community composition reflects structural,trophic and physicochemical factors

(1) A study of the metazoan community occurring in water-filled tree-holes in southern Germany has been performed to determine the relationships among the key species of arthropods found within the community and a range of structural, physical and chemical factors, using multivariate techniques. (2) Four animal species were sufficiently common to allow identification of the preferred environments for their larvae. The aedine mosquito, Aedes geniculatus, prefers shallow open tree-holes with relatively little leaf litter even though these may represent less permanent water-bodies. The scirtid beetle, Prionocyhon serricornis, occurs in larger, deeper holes with greater amounts of leaf litter and a more predictable aquatic environment, although open water is not a requisite. Larvae of the orthocladiine chironomid, Metriocnemus cavicola, favours shallow more open tree-holes with higher litter content but with sufficient open water to ensure an adequate oxygen supply. The eristaline syrphid, Myatropa florea, favours shallow, open tree-holes with low litter content. (3) There is no evidence that interspecific interactions affect the distribution or abundance of any of these species. (4) The autecological results are discussed in light of those available for phytotelm dwellers elsewhere. The food-web overall may be interpreted as so simple that it is driven by ‘bottom-up’ environmental factors with no part played by those community-level ‘top-down’ processes that may be adduced for more complex, multi-trophic level webs occurring elsewhere. No “processing chain commensalism” could be found in the arthropod community of the temperate German deciduous tree-hole dwellers. Handling editor: K. Martens     

Steroidal saponins from the roots of Asparagus racemosus

Five steroidal saponins, shatavarins VI-X, together with five known saponins, shatavarin I (or asparoside B), shatavarin IV (or asparinin B), shatavarin V, immunoside and schidigerasaponin D5 (or asparanin A), have been isolated from the roots of Asparagus racemosus by RP-HPLC and characterized by spectroscopic (1D and 2D NMR experiments) and spectrometric (LCMS) methods.     

Drivers of moth species richness on tropical altitudinal gradients: a cross-regional comparison

Aims We examine the role of species–area relationships (SARs), climatic parameters and phylogeny in shaping the altitudinal species richness patterns of moths. With respect to SARs, we investigate whether habitat heterogeneity is a probable mechanism for mediating area effects. We investigate the consistency of patterns by comparing several discrete regions. Location Nine mountainous regions in tropical Asia and the Malay Archipelago. Methods Presence‐only records for 292 species of the Lepidopteran family Sphingidae were used to measure interpolated species richness in 200‐m altitudinal bands. Species richness was correlated with area measures, which were calculated from both two‐dimensional map projections and three‐dimensional digital elevation models (DEMs). We used data simulations of homogeneous communities to test for effects of sample (i.e. habitat) heterogeneity as a mechanism causing SARs. Species richness patterns were compared among regions and between the two major sphingid clades, and were related to regional climatic characteristics. Results The area of altitudinal bands was a strong (statistical) explanation of species richness, particularly if area was calculated from three‐dimensional DEMs, but SARs often over‐predict species richness in lowland areas. There was no evidence for habitat heterogeneity as a mechanism of altitudinal SARs (tested for Borneo only). Species richness patterns varied considerably between the nine regions, which may, as an alternative to SARs, be explained by climatic differences such as (temperature) seasonality. Phylogenetic clades differed in species richness patterns exhibited. Main conclusion SARs provide strong empirical explanations for (regional) altitudinal patterns of species richness, but lack of evidence for the most likely mechanism cautions against a priori ‘corrections’ of species richness data for area. Furthermore, SARs are often not a sufficient explanation for the drop in species richness towards lowlands. Climate, or other collinear variables, may offer alternative explanations for altitudinal SARs. More research is needed to understand the mechanisms for SARs in an altitudinal context in order to evaluate their importance in the face of parameter collinearity.     

Phylogeny and Biogeography of Hawkmoths (Lepidoptera: Sphingidae): Evidence from Five Nuclear Genes

Background

The 1400 species of hawkmoths (Lepidoptera: Sphingidae) comprise one of most conspicuous and well-studied groups of insects, and provide model systems for diverse biological disciplines. However, a robust phylogenetic framework for the family is currently lacking. Morphology is unable to confidently determine relationships among most groups. As a major step toward understanding relationships of this model group, we have undertaken the first large-scale molecular phylogenetic analysis of hawkmoths representing all subfamilies, tribes and subtribes.

Methodology/Principal Findings

The data set consisted of 131 sphingid species and 6793 bp of sequence from five protein-coding nuclear genes. Maximum likelihood and parsimony analyses provided strong support for more than two-thirds of all nodes, including strong signal for or against nearly all of the fifteen current subfamily, tribal and sub-tribal groupings. Monophyly was strongly supported for some of these, including Macroglossinae, Sphinginae, Acherontiini, Ambulycini, Philampelini, Choerocampina, and Hemarina. Other groupings proved para- or polyphyletic, and will need significant redefinition; these include Smerinthinae, Smerinthini, Sphingini, Sphingulini, Dilophonotini, Dilophonotina, Macroglossini, and Macroglossina. The basal divergence, strongly supported, is between Macroglossinae and Smerinthinae+Sphinginae. All genes contribute significantly to the signal from the combined data set, and there is little conflict between genes. Ancestral state reconstruction reveals multiple separate origins of New World and Old World radiations.

Conclusions/Significance

Our study provides the first comprehensive phylogeny of one of the most conspicuous and well-studied insects. The molecular phylogeny challenges current concepts of Sphingidae based on morphology, and provides a foundation for a new classification. While there are multiple independent origins of New World and Old World radiations, we conclude that broad-scale geographic distribution in hawkmoths is more phylogenetically conserved than previously postulated.     

Size-Class Effect Contributes to Tree Species Assembly through Influencing Dispersal in Tropical Forests

We have investigated the processes of community assembly using size classes of trees. Specifically our work examined (1) whether point process models incorporating an effect of size-class produce more realistic summary outcomes than do models without this effect; (2) which of three selected models incorporating, respectively environmental effects, dispersal and the joint-effect of both of these, is most useful in explaining species-area relationships (SARs) and point dispersion patterns. For this evaluation we used tree species data from the 50-ha forest dynamics plot in Barro Colorado Island, Panama and the comparable 20 ha plot at Bubeng, Southwest China. Our results demonstrated that incorporating an size-class effect dramatically improved the SAR estimation at both the plots when the dispersal only model was used. The joint effect model produced similar improvement but only for the 50-ha plot in Panama. The point patterns results were not improved by incorporation of size-class effects using any of the three models. Our results indicate that dispersal is likely to be a key process determining both SARs and point patterns. The environment-only model and joint-effects model were effective at the species level and the community level, respectively. We conclude that it is critical to use multiple summary characteristics when modelling spatial patterns at the species and community levels if a comprehensive understanding of the ecological processes that shape species’ distributions is sought; without this results may have inherent biases. By influencing dispersal, the effect of size-class contributes to species assembly and enhances our understanding of species coexistence.     

不同胁迫预处理提高水稻幼苗抗寒性期间蛋白质的变化

水稻(Oryza sativa L.)幼苗经盐、热激和冷三种不同胁迫预处理均提高了幼苗的抗寒性。与未预处理苗相比,在处理后、低温伤害后和常温下恢复2d的三个时期,不同胁迫预处理苗的可溶性和热不稳定蛋白含量变化趋势甚为相似,但热稳定蛋白含量变化则各有异同。SDS-PAGE图谱分析显示,不同胁迫预处理提高水稻幼苗抗寒性时,其可溶性蛋白、热稳定和热不稳定蛋白组成变化亦各有异同。除诱导出共有的新多肽外,还各自诱导出特有的新多肽。结果表明,植物对不同胁迫的交叉适应存在一定的共同机理,但亦可看出植物对同一种环境胁迫似乎不是以同一的机理去适应。