Search results for "Predator"
showing 10 items of 349 documents
Replacement of fishmeal with corn gluten meal in feeds for juvenile rainbow trout (Oncorhynchus mykiss) does not affect oxygen consumption during for…
2017
Abstract We compared oxygen consumption (MO 2 , mg/kg/h) of c. 80 g rainbow trout ( Oncorhynchus mykiss ) in an intermittent-flow swim respirometer at 15 °C. Before the tests the fish were grown in flow through tanks (15 °C) with either fishmeal (FM) or corn gluten meal (CGM) based diets (c. 52% protein) for a period of 3–4.5 months. Ten individuals from both treatment groups were fasted for 48 h before the swim test, which consisted of 18 loops of 210 s over three different periods: acclimation period (6 loops at 0.5 body lengths per s, BL/s), exercise period (8 loops at increased speed from 1 to 2.5 BL/s with recovery loops at 0.5 BL/s), and a recovery period (four loops at 0.5 BL/s). We …
Unexpected diversity in socially synchronized rhythms of shorebirds.
2016
The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment1,2,3,4. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions1,5, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators6,7,8,9,10. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring)6,7,8,9,11. The behavioural rhythms that em…
The protective value of a defensive display varies with the experience of wild predators
2019
AbstractPredation has driven the evolution of diverse adaptations for defence among prey, and one striking example is the deimatic display. While such displays can resemble, or indeed co-occur with, aposematic ‘warning’ signals, theory suggests deimatic displays may function independently of predator learning. The survival value of deimatic displays against wild predators has not been tested before. Here we used the mountain katydid Acripeza reticulata to test the efficacy of a putative deimatic display in the wild. Mountain katydids have a complex defence strategy; they are camouflaged at rest, but reveal a striking red-, blue-, and black-banded abdomen when attacked. We presented live kat…
Trematode cercariae as prey for zooplankton: effect on fitness traits of predators.
2019
AbstractRemoval of parasite free-living stages by predators has previously been suggested an important factor controlling parasite transmission in aquatic habitats. Experimental studies of zooplankton predation on macroparasite larvae are, however, scarce. We tested whether trematode cercariae, which are often numerous in shallow waters, are suitable prey for syntopic zooplankters. Feeding rates and survival of freshwater cyclopoids (Megacyclops viridis, Macrocyclops distinctus), calanoids (Arctodiaptomus paulseni), cladocerans (Sida crystallina) and rotifers Asplanchna spp., fed with cercariae of Diplostomum pseudospathaceum, a common fish trematode, were studied. In additional long-term e…
Citations and metrics of journals discontinued from Scopus for publication concerns: the GhoS(t)copus Project
2020
Background: Scopus is a leading bibliometric database. It contains a large part of the articles cited in peer-reviewed publications. The journals included in Scopus are periodically re-evaluated to ensure they meet indexing criteria and some journals might be discontinued for 'publication concerns'. Previously published articles may remain indexed and can be cited. Their metrics have yet to be studied. This study aimed to evaluate the main features and metrics of journals discontinued from Scopus for publication concerns, before and after their discontinuation, and to determine the extent of predatory journals among the discontinued journals. Methods: We surveyed the list of discontinued jo…
Outside-host predation as a biological control against an environmental opportunist disease
2017
Abstract Environmentally growing opportunist pathogens are a common threat to human health and food production. Due to environmental growth of the pathogen, these diseases are difficult to control with disinfectants and antibiotics. Thus, there is a need for sustainable and effective control methods against environmentally growing opportunist diseases. Predation is often a major limiting factor in the outside host environment. Here we propose that it could be used in the biological control of these diseases. We introduce a novel epidemiological model for environmentally growing opportunists combining pathogen growth within-host (SI model) and outside-host into classical predator-prey model.…
Plēsonīgo cenu jēdziens Latvijas konkurences tiesībās
2015
Plēsonīgo cenu stratēģijas realizēšana Latvijas doktrīnā līdz šim nav apskatīta. Lielākā problēma, kas saistīta ar plēsonīgajām cenām, ir plēsonīgo cenu piemērošanas nošķiršana no ikdienišķas biznesa prakses. Eiropas Savienības doktrīnā un Eiropas Savienības Tiesas praksē ir nostiprināti dažādi kritēriji, meklējot risinājumu iepriekš minētajai problēmai. Autors pētījuma gaitā analizē plēsonīgo cenu jēdzienu, kā arī Eiropas Savienības Tiesas praksi un tās piedāvātos kritērijus plēsonīgo cenu piemērošanas identificēšanai. Tāpat darba gaitā autors salīdzina Konkurences padomes nolēmumos nostiprinātos kritērijus ar Eiropas Savienības Tiesas praksi. Darbā, cita starpā, autors analizē arī Amerika…
Effects ofBacillus thuringiensisCry1Ab and Cry3Aa endotoxins on predatory Coleoptera tested through artificial diet-incorporation bioassays
2009
AbstractTraditional approaches to studying the effects of genetically modified (GM) crops on beneficial insects involve either field assays, comparing insect population levels between control and GM crops or tritrophic bioassays with contaminated insects – usually larvae or eggs of Lepidoptera – as preys. Here, we report the results of a bioassay using an artificial diet, suitable for predatory Coleoptera, to supplyBacillus thuringiensis(Bt) solubilized Cry1Ab and Cry3Aa as well as trypsin-activated Cry1Ab toAtheta coriariaandCryptolaemus montrouzieriadults and young larvae ofAdalia bipunctata. Water, solubilization buffer and trypsin-treated solubilization buffer were used as controls. In …
Does predation maintain eyespot plasticity in Bicyclus anynana?
2004
The butterfly Bicyclus anynana exhibits phenotypic plasticity involving the wet-season phenotype, which possesses marginal eyespots on the ventral surface of the wings, and the dry-season form, which lacks these eyespots. We examined the adaptive value of phenotypic plasticity of B. anynana in relation to the defence mechanisms of crypsis and deflection. We assessed the visibility differences between spotless and spotted butterflies against backgrounds of brown (dry season) or green (wet season) leaves. Spotless butterflies were highly cryptic and less predated by adult bird predators than were spotted ones when presented against brown leaf litter. However, the advantage of crypsis disappea…
Do properties and species of weed seeds affect their consumption by carabid beetles?
2019
International audience; Seed predators are an integral part of agroecosystems, where they can reduce the populations of weeds. The preference of predators for seeds and the observed predation rate may be affected by the properties of seeds (e.g. taxonomy, chemical composition, physical defence). In this work, we focused on seed consumption of Taraxacum officinale Web. and Stellaria media (L.) Vill., from France and the Czech Republic, by three species of ground beetle that are seed predators (Coleoptera: Carabidae): Poecilus cupreus (L.), Pterostichus melanarius (Illiger) and Anchomenus dorsalis (Pontoppidan). The seed species were offered in arenas, simultaneously, under three different ex…