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Group living can incur both benefits and costs, mediated by different mechanisms. In many gregarious caterpillars, collective use of a network of silk trails is thought to improve foraging. Grouping, i.e., close contact with conspecifics, has been postulated to have both positive (thermoregulation and predator defense) and negative (competition and pathogen transmission) effects. The present experiment distinguishes between silk produced by group members and grouping per se in their effects on growth and development of both early and late larval stadia of the forest tent caterpillar [Malacosoma disstria Hübner (Lepidoptera: Lasiocampidae)] in a laboratory context. For both developmental stadia tested, pre‐established silk trails decreased latency to food finding and hence increased food consumption and growth rate. For younger larvae, pre‐established silk also decreased investment in silk production. Grouping young caterpillars accelerated development at the expense of growth, possibly as a mechanism to avoid intraspecific competition in later larval stadia. In older caterpillars, grouping decreased meal duration, suggesting that competition can indeed occur towards the end of larval development, even in the presence of surplus food. This led to a decrease in growth without any effect on instar duration. The benefits of exogenous silk thus decreased during larval development, whereas the costs associated with crowding increased. Ontogenetic shifts in grouping are common in many taxa: the present study is among the first to provide empirical evidence for an adaptive explanation of observed ontogenetic changes in aggregative behavior. 相似文献
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An evaluation of semi‐automated methods for collecting ecosystem‐level data in temperate marine systems 下载免费PDF全文
Kingsley J. Griffin Luke H. Hedge Manuel González‐Rivero Ove I. Hoegh‐Guldberg Emma L. Johnston 《Ecology and evolution》2017,7(13):4640-4650
Historically, marine ecologists have lacked efficient tools that are capable of capturing detailed species distribution data over large areas. Emerging technologies such as high‐resolution imaging and associated machine‐learning image‐scoring software are providing new tools to map species over large areas in the ocean. Here, we combine a novel diver propulsion vehicle (DPV) imaging system with free‐to‐use machine‐learning software to semi‐automatically generate dense and widespread abundance records of a habitat‐forming algae over ~5,000 m2 of temperate reef. We employ replicable spatial techniques to test the effectiveness of traditional diver‐based sampling, and better understand the distribution and spatial arrangement of one key algal species. We found that the effectiveness of a traditional survey depended on the level of spatial structuring, and generally 10–20 transects (50 × 1 m) were required to obtain reliable results. This represents 2–20 times greater replication than have been collected in previous studies. Furthermore, we demonstrate the usefulness of fine‐resolution distribution modeling for understanding patterns in canopy algae cover at multiple spatial scales, and discuss applications to other marine habitats. Our analyses demonstrate that semi‐automated methods of data gathering and processing provide more accurate results than traditional methods for describing habitat structure at seascape scales, and therefore represent vastly improved techniques for understanding and managing marine seascapes. 相似文献
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Maurício da Fonseca Maria João Jurak Edita Kataja Kim Master Emma R. Berrin Jean-Guy Stals Ingeborg Desmet Tom Van Landschoot Anita Briers Yves 《Applied microbiology and biotechnology》2018,102(23):10091-10102
Applied Microbiology and Biotechnology - Carbohydrate-active enzyme discovery is often not accompanied by experimental validation, demonstrating the need for techniques to analyze substrate... 相似文献
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In the face of demands for researchers to engage more actively with a wider range of publics and to capture different kinds of research impacts and engagements, we explored the ways a small number of environmental researchers use traditional and social media to disseminate research. A questionnaire was developed to investigate the impact of different media as a tool to broker contact between researchers and a variety of different stakeholders (for example, publics, other researchers, policymakers, journalists) as well as how researchers perceive that their use of these media has changed over the past five years. The questionnaire was sent to 504 researchers whose work had featured in a policy-oriented e-news service. 149 valid responses were received (29%). Coverage in traditional media (newspapers, broadcast) not only brokers contact with other journalists, but is a good source of contact from other researchers (n=47, 62%) and members of the public (n=36, 26%). Although the use of social media was limited amongst our sample, it did broker contact with other researchers (n=17, 47%) and the public (n=10, 28%). Nevertheless, few environmental researchers were actively using social media to disseminate their research findings, with many continuing to rely on academic journals and face-to-face communication to reach both academic and public audiences. 相似文献
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A conventional extraction technique of sonication has been compared, in terms of extraction efficiency, extraction time and amount of solvent, with the more novel technique of accelerated solvent extraction for the extraction of kavain from the powdered roots of Piper methysticum (Kava) with acetone. The extracts were analysed using high-performance liquid chromatography with ultra violet detection. The effects of varying solvent volume and extraction time upon the quantity of kavain extracted with sonication, and the effects of varying temperature upon the kavain extraction efficiency by ASE, were investigated. ASE was found to be more efficient with respect to time and solvent volume required; however, a good agreement was found between the kavain concentration obtained using both extraction techniques. 相似文献
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