60 research outputs found

    Dispersal of individuals of the flightless grassland ground beetle, Carabus hungaricus (Coleoptera: Carabidae), in three populations and what they tell us about mobility estimates based on mark-recapture

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    Knowledge of the dispersal ability of endangered species is crucial for developing effective, evidence-based conservation policies. Due to their limited dispersal abilities and specific habitat requirements, insects are among the animals most threatened by habitat fragmentation. We studied three populations of the highly endangered species of ground beetle, Carabus hungaricus, at three sites in Central Europe (Hungary and Czech Republic) using mark-release-recapture (MRR). The total catch of 574 pitfall traps set at the three sites was 6255 individuals. Depending on the site, the percentage recaptured was 13–32%. average and maximum distance moved by individuals of both sexes at each of the sites ranged between 47–132 and 207–1104 m, respectively. The probability of the movements following an inverse power function (IPF) for the two sexes did not differ, but did differ among sites. Probability of dispers- ing for distances >100 m differed by an order of magnitude between sites, most likely because of differences in how the samples were collected. Despite the fact that individual beetles are able to move over distances in the order of kilometres, the high fragmentation of their habitats is likely to prevent them from colonizing most uninhabited habitat patches. Therefore, the conservation of this threatened ground beetle could be improved by adopting and implementing a policy of assisted dispersal. Our results from three study sites also provide an interesting illustration of the variability in the estimates of the probability of dispersal obtained using MRR

    Protection from herbivores varies among ant genera for the myrmecophilic plant Leea aculeata in Malaysian Borneo

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    Some plants use food bodies to attract ants that then provide protection from herbivory. A brief report from 1898 describes the myrmecophilic plant Leea aculeata Bl. as bearing food bodies on its young shoots, which accumulate when they are not harvested by ants. However, ant efficacy in deterring herbivores and consequences for herbivory rates remain unknown. Here we investigate (1) which ant taxa patrol these plants and whether they remove significant numbers of food bodies, (2) if these ants attack herbivores, and (3) if any anti-herbivore activity correlates negatively with herbivory. We found that a diverse community of ants patrolled young L. aculeata shoots and removed food bodies (1.2 food body per cm2 per 24 h), with food bodies accumulating when ants are experimentally excluded. Attack rates on surrogate herbivores (termite baits) differed among ant genera, with Crematogaster and Lophomyrmex being most active. Although herbivory did not differ among ant genera, herbivory was greater when ants took a longer time to detect herbivores and recruit fellow ants, providing evidence for the mutualism of L. aculeata with ants. However, the variation in protection among ant genera raises questions regarding the stability of this mutualism in the face of exploitation by ants

    Extracellular vimentin is sufficient to promote cell attachment, spreading, and motility by a mechanism involving N-acetyl glucosamine-containing structures

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    Vimentin intermediate !laments form part of the cytoskeleton of mesenchymal cells, but under pathological conditions often associatedwith in ammation, vimentin !laments depolymerize as the result of phosphorylation or citrullination, and vimentin oligomers are secreted or released into the extracellular environment. In the extracellular space, vimentin can bind surfaces of cells and the extracellular matrix, and the interaction between extracellular vimentin and cells can trigger changes in cellular functions, such as activation of !broblasts to a !brotic phenotype. The mechanism by which extracellular vimentin binds external cell membranes and whether vimentin alone can act as an adhesive anchor for cells is largely uncharacterized. Here, we show that various cell types (normal and vimentin null !broblasts, mesenchymal stem cells, and A549 lung carcinoma cells) attach to and spread on polyacrylamide hydrogel substrates covalently linked to vimentin. Using traction force microscopy and spheroid expansion assays, we characterize how different cell types respond to extracellular vimentin. Cell attachment to and spreading on vimentin-coated surfaces is inhibited by hyaluronic acid degrading enzymes, hyaluronic acid synthase inhibitors, soluble heparin or N-acetyl glucosamine, all of which are treatments that have little or no effect on the same cell types binding to collagen-coated hydrogels. These studies highlight the effectiveness of substratebound vimentin as a ligand for cells and suggest that carbohydrate structures, including the glycocalyx and glycosylated cell surface proteins that contain N-acetyl glucosamine, form a novel class of adhesion receptors for extracellular vimentin that can either directly support cell adhesion to a substrate or !ne-tune the glycocalyx adhesive properties

    Gap felling as a forest harvesting method in boreal forests : responses of carabid beetles (Coleoptera, Carabidae)

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    In order to study the ecological effects of logging combined with mechanical soil preparation, we sampled carabid beetles with pitfall trapping in nine spruce-dominated stands in central Finland in 1995–1998. Three of the stands were left intact as controls. Three 1600-m2 openings per stand were logged in the winter 1995–1996 into six stands. In three of these stands, light soil preparation was applied. Logging affected the species assemblages, but soil preparation per se had no clear effects. Open-habitat species increased in abundance in the openings one year after logging, but catches of generalist species in the different treatments did not differ from each other. A forest species, Calathus micropterus, was least abundant in the prepared openings. The amounts of logging residue, exposed mineral soil and aggregated humus, as well as the abundance of red wood ants, significantly explained variation in carabid assemblages
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