关键词： Aeorestes   Dasypterus   Hawaiian hoary bat   Lasiurus   molecular phylogenetics   tree bats  

摘要： This study reports the phylogenetic relationships of 13 species of lasiurine bats using 4 loci from mitochondrial and Y-chromosomal DNA. Our results support a sister taxon relationship between the red and hoary bats, with the yellow bats being more distantly related. Several taxonomic revisions are suggested based on the results of this study. We support the recognition of 3 separate genera: Lasiurus (red bats), Dasypterus (yellow bats), and Aeorestes (hoary bats, including A. egregius which groups more closely to the hoary bats than its traditional placement with the red bats). We recognize L. frantzii as a distinct species and recognize L. blossevillii salinae as a subspecies rather than species. We elevate 3 previously recognized subspecies of A. cinereus to specific status. The phylogeography of the endangered Hawaiian hoary bat is studied in detail, and hoary bats are found to have undergone multiple invasions of the Hawaiian Islands from North America over its evolutionary history. We also report the presence of 2 species of Aeorestes on the Hawaiian Islands where only one previously had been known.

关键词： FOREST ecology   PLANT species diversity   PLANT resistance to insects   PLANT growth   TREE farms  

摘要： Tree diversity is an important driver of forest ecosystem functioning, hypothesised to enhance tree growth and resistance to herbivores. To test this, we assessed the relative importance of tree species richness and functional diversity on tree height growth and insect herbivore damage across three tree diversity experiments in Finland, France and Germany, established within the last fifteen years. These experiments encompass species richness gradients from monocultures up to five species mixtures, with compositions drawn from a pool of eleven tree species. Tree height growth and total insect herbivory were evaluated at both the tree species and forest plot scales. Trees in mixtures tended to grow taller, but on average received more insect herbivory relative to monocultures. Gradients of tree species richness or functional diversity had only weak impact on the magnitude of these effects. Community weighted means of specific leaf area alone captured diversity effects on tree height growth, with stronger positive effects of diversity in mixtures with high community SLA. Tree species-specific responses were highly variable. No species significantly benefited both in terms of increased growth and reduced herbivory when grown in mixtures. More species showed positive height growth responses in mixed assemblages, but only the two exotic conifers experienced associational resistance to herbivores. This large-scale study shows that tree height growth in young forest plantations tends to be higher in species mixtures than in monocultures, but incremental increases in functional diversity have, at best, weak marginal growth benefits. Moreover, there appear to be contrasting effects at forest plot versus individual species scales. Thus, while some species show lower herbivore damage in mixtures, this is not a consistent trend and contrasts the higher overall damage in mixtures observed at the forest plot scale. To improve both tree growth and resistance to herbivores in tree

关键词： Potassium salts of fatty acids   Organic almond production   Prunus dulcis   Hemiptera   Tingidae  

摘要： Monosteira unicostata (Mulsant & Rey) (Hemiptera: Tingidae) is an important pest of almond trees in the Mediterranean region requiring alternative control methods for organic farming. Kaolin and potassium salts of fatty acids combined with thyme essential oil (PSTEO) have shown high efficacy for the control of this insect in laboratory assays. Field studies were conducted during two consecutive years to test the feasibility of these products applied at the maximum field recommended concentrations to control this pest and other arthropods that damage almond trees. In 2009, two kaolin applications reduced the abundance of M. unicostata approximately by half, whereas in 2010, identical applications reduced the abundance by a third. This produced a damage reduction of 26 and 11 %, respectively. Concerning PSTEO, a 40 % reduction in M. unicostata abundance was obtained in 2009, producing a 14 % damage reduction, whereas no significant effect was observed in 2010. The effect of the treatments on M. unicostata was only observed at the lower part of the trees. Other phytophagous arthropods of almond trees, such as Cicadellidae, Aphididae, Bryobia rubrioculus (Scheuten) (Acari: Tetranychidae) and Phyllonorycter corylifoliella Hubner (Lepidoptera: Gracillariidae), were also negatively affected by kaolin treatments, but PSTEO had no effect on herbivorous arthropods other than M. unicostata. Kaolin could be useful to control M. unicostata in the field, but repeated applications might be required to achieve good tree coverage and pest control. PSTEO appears more limited in its efficacy.

关键词： Bottom-up versus top-down effects   Functional divergence   Functional evenness   Functional richness   Spatial heterogeneity   Termitaria  

摘要： Spatially heterogeneous habitats often promote woody plant species and functional diversity (FD). Ungulate herbivory can have the opposite effect. Across the globe, the type and intensity of herbivory is changing, as domestic livestock replace wild ungulates, which are increasingly confined to protected areas. Despite recognition of the importance of FD for ecosystem functioning, the interactive effect of soil-related fine-scale heterogeneity and larger-scale ungulate herbivory on woody plant FD is little-known. In miombo woodland of Zimbabwe, we investigated (1) how bottom-up fine-scale heterogeneity created by Macrotermes termitaria interacts with top-down effects of herbivore foraging-guilds on woody plant FD;and (2) whether browsing combined with grazing impacts FD more than grazing alone. The three different herbivore treatments (grazing, combined browsing-and-grazing, and exclusion) had been maintained for 50 years. We surveyed 10 termite mound-matrix plots within three sites per treatment. We assessed woody plant traits and FD across treatments (herbivore feeding-guild) and position (mound or woodland-matrix), and interactive effects between these. Woody plant FD was greater on mounds, and lowest overall with browsing-and-grazing. Specific traits were associated with position (e.g. palatability was greater for mounds), and treatment (e.g. spinescence increased with grazing). Long-term enclosure of ungulate herbivores (browsing-and-grazing, and grazing alone) decreased woody FD, but this was mitigated by termitaria. The novel finding is that at regional scales, mounds can enhance woody plant FD despite the impacts of herbivory. At broader scales encompassing the miombo system, potential exists for mounds to stabilise woody plant FD from livestock-induced impacts.

关键词： fire   herbivory   Mali   savannah   tree harvest   West Africa  

摘要： Theory and empirical evidence for the impacts of fire and herbivory in savannahs is well established - they are top-down disturbances that maintain savannahs in disequilibrium states away from potential tree cover. In African savannahs, the demand for fuelwood is extremely high, so tree harvest likely also has an impact, both directly and indirectly, on tree cover, density and biomass. Many savannah trees resprout vigorously from the base after harvest. However, harvested trees regenerate as saplings susceptible to fire and browsing, so harvest may have important demographic consequences. Here, we report the effects of tree harvest, and its interaction with fire and herbivory, on savannah dynamics by analysing woody regrowth following a harvest in arid Sahelian and mesic Guinean savannahs in Mali, West Africa. Tree harvest resulted in an overall reduction in wood production per tree compared to growth in nonharvested trees. Regrowth, either biomass or height, did not differ among fire and herbivory treatments. Our results suggest that the resprouting abilities that savannah trees have evolved to cope with frequent fire are essential for surviving tree harvest and subsequent disturbance. In these savannahs, regrowth is rapid enough in the first growing season to escape the impact of dry season fires.

关键词： PREDATORY animals   FICTION  

关键词： Polysaccharide   Anacardiaceae   Diarrheal models   Cholera   Castor oil  

摘要： Ethnopharmacological relevance: Anacardium occidentale L. (Anacardiaceae) is commonly known as the cashew tree. It is native to tropical America and extracts of the leaves, bark, roots, chestnut net and exudate have been traditionally used in northeast Brazil for the treatment of various diseases. The exudate of the cashew tree (cashew gum) has been exploited by locals since ancient times for multiple applications, including the treatment of diarrheal diseases. Aim of the study: The primary aim of the present study is to evaluate the antidiarrheal activity of cashew gum (CG), a complex heteropolysaccharide from the exudate of the cashew tree, using various models. Materials and methods: The antidiarrheal activity of cashew gum (CG) against acute diarrhea was investigated using the castor oil-induced diarrhea model. The effects of CG on gastrointestinal transit and castor oil- and PGE(2)- induced enteropooling were also examined in rodents. In addition, the effect of CG against secretory diarrhea was investigated using a model of fluid secretion in cholera toxin-treated intestinal closed loops in live mice. Results: Cashew gum (30, 60, and 90 mg/kg, p.o.) showed a significant (P <0.05-0.01) antidiarrheal effect in rats with castor oil-induced diarrhea, inhibiting the total amount of stool and diarrheal stools. The 60 mg/kg dose of CG exhibited excellent antidiarrheal activity and significantly reduced the severity of diarrhea (diarrhea scores) in rats. CG (60 mg/kg) significantly (P < 0.05) decreased the volume of castor oil- and PGE(2)-induced intestinal fluid secretion (enteropooling). In addition, similar to loperamide (standard drug, 5 mg/kg, p.o.), CG treatment reduced the distance traveled by a charcoal meal in the 30-mm gastrointestinal transit model by interacting with opioid receptors. In cholera toxin-induced secretory diarrhea, CG (60 mg/kg) significantly inhibited the intestinal fluid secretion and decreased Cl- ion loss in the cholera toxin treated isola

关键词： browsing megaherbivores   compounded disturbances   context-dependent responses   contingency   controlled burning   ecosystem engineers   habitat facilitation   keystone species   large mammalian herbivores   transiently synergistic indirect effects  

摘要： Disturbance is a crucial determinant of animal abundance, distribution and community structure in many ecosystems, but the ways in which multiple disturbance types interact remain poorly understood. The effects of multiple-disturbance interactions can be additive, subadditive or super-additive (synergistic). Synergistic effects in particular can accelerate ecological change;thus, characterizing such synergies, the conditions under which they arise, and how long they persist has been identified as a major goal of ecology. We factorially manipulated two principal sources of disturbance in African savannas, fire and elephants, and measured their independent and interactive effects on the numerically dominant vertebrate (the arboreal gekkonid lizard Lygodactylus keniensis) and invertebrate (a guild of symbiotic Acacia ants) animal species in a semi-arid Kenyan savanna. Elephant exclusion alone (minus fire) had negligible effects on gecko density. Fire alone (minus elephants) had negligible effects on gecko density after 4months, but increased gecko density twofold after 16months, likely because the decay of fire-damaged woody biomass created refuges and nest sites for geckos. In the presence of elephants, fire increased gecko density nearly threefold within 4months of the experimental burn;this occurred because fire increased the incidence of elephant damage to trees, which in turn improved microhabitat quality for geckos. However, this synergistic positive effect of fire and elephants attenuated over the ensuing year, such that only the main effect of fire was evident after 16months. Fire also altered the structure of symbiotic plant-ant assemblages occupying the dominant tree species (Acacia drepanolobium);this influenced gecko habitat selection but did not explain the synergistic effect of fire and elephants. However, fire-driven shifts in plant-ant occupancy may have indirectly mediated this effect by increasing trees' susceptibility to elephant damage. Our findings

关键词： animal model   cardiac transplantation   Chinese tree shrews   xenograft rejection   xenotransplantation  

摘要： Since -1,3-galactosyltransferase knockout (GalT-KO) pigs became available, there has been an increasing interest in non-Gal natural antibody (nAb)-mediated xenograft rejection. To better understand mechanisms of non-Gal nAb-mediated rejection, a simple small animal model without gene manipulation would be extremely valuable. Here, we tested whether the Chinese tree shrew (CTS), which is a small-sized mammal that is phylogenetically close to primates, could serve as a model for discordant xenograft rejection. MethodsStudy 1: Expression of -Gal antigens in hearts and kidneys of CTSs and rats was assessed by IB4 lectin binding. Presence of anti-Gal and anti-non-Gal IgM and IgG nAb in CTS sera was tested by FACS using Gal+ and GalTKO PBMC as well as BSA-ELISA. Study 2: Rat hearts were transplanted into CTS recipients (group 1, n = 7), and CTS hearts were transplanted in rats [n = 10;seven received no immunosuppression (group 2) and three received FK506 + leflunomide (group 3)]. ResultsStudy 1: Both CTSs and rats had -Gal expression in hearts and kidneys. ELISA showed CTSs do not have anti-Gal nAb, and flow cytometry indicated CTSs have anti-non-Gal IgM and IgG nAb in serum. Study 2: Rat hearts in CTSs were uniformly rejected within 35 mins, while CTS hearts in rats continued beating until day 5 without immunosuppression, and up to day 8 with immunosuppression. ConclusionRat-to-CTS heart transplantation is a discordant xenotransplant model, CTS-to-Rat heart transplantation is a concordant xenotransplant model. CTSs are valuable small animals to study mechanisms and strategies to avoid non-Gal nAb-mediated xenograft rejection.

关键词： Herbivores   Insect-plant relationships   Plant diversity   Plant genetics   Tree growth  

摘要： [ Although the effects of plant diversity on herbivores are contingent upon herbivore traits and the source of plant diversity (e.g. intra-and interspecific), most studies have analyzed these effects separately. We compared the effects of genotypic diversity of big-leaf mahogany Swietenia macrophylla with that of tree species diversity on two specialist caterpillars (Hypsipyla grandella stem borers and Phyllocnistis meliacella leaf miners) and three generalist leafhoppers (Cicadellidae) feeding on mahogany in a large-scale (7.2 ha) forest diversity experiment in southern Mexico. The experiment consisted of fifty-nine 21 x 21-m plots, with 64 tree saplings each (3-m spacing between plants). Plots were either mahogany monocultures or species polycultures of four species (including mahogany) and - within each of these two plot types - mahogany was represented by either one or four genotypes. Throughout a five-month period, beginning six months after planting, we measured mahogany growth and monitored herbivore and predator (spider) abundance. We found no effect of mahogany genotypic diversity on either specialist caterpillars or generalist leafhoppers, and this result was consistent across levels of tree species diversity. In contrast, species diversity had significant effects on both specialists but neither of the generalist herbivores. Specifically, species diversity lowered H. grandella attack at the middle of the sampling season, but increased attack at the end of the season, whereas P. meliacella abundance was consistently reduced. Such effects were not mediated by effects of species diversity on plant growth (of which there were none), but rather through resource heterogeneity. Diversity did not influence spider abundance. This study is one of few to directly compare sources of plant diversity, and uniquely compares such effects among herbivores with contrasting life histories (e.g. diet breadths). Overall, we demonstrate that plant species diversity effects outw