Search results for "BLA"
showing 10 items of 5738 documents
Community structure affects trophic ontogeny in a predatory fish.
2016
While most studies have focused on the timing and nature of ontogenetic niche shifts, information is scarce about the effects of community structure on trophic ontogeny of top predators. We investigated how community structure affects ontogenetic niche shifts (i.e., relationships between body length, trophic position, and individual dietary specialization) of a predatory fish, brown trout (Salmo trutta). We used stable isotope and stomach content analyses to test how functional characteristics of lake fish community compositions (competition and prey availability) modulate niche shifts in terms of (i) piscivorous behavior, (ii) trophic position, and (iii) individual dietary specialization. …
Age, condition and dominance-related sexual ornament size before and during the breeding season in the black grouse Lyrurus tetrix
2018
Male ornaments function as honest cues of male quality in many species and are subject to intra- and intersexual selection. These ornaments are generally studied during peak expression, however their size outside the breeding season may determine ultimate ornament size and costliness, and as such reproductive success. We investigated whether male black grouse Lyrurus tetrix eye comb size was related to age, condition and measures of male dominance before and during the breeding season. Total combined eye comb size began to increase ~70 d before the start of the breeding season. Adult males (aged ≥ 2 yr old) had consistently larger eye combs than younger males (1 yr old) both before and duri…
Are small protected habitat patches within boreal production forests effective in conserving species richness, abundance and community composition? :…
2021
Abstract Background In boreal zone forest management is changing and degrading forest habitats, which has caused declines in biodiversity. To mitigate these harmful effects in production forests, small-scale habitats with high biodiversity values have been protected within them. These habitats include woodland key habitats, and other small habitat patches protected by voluntary conservation actions. In this systematic review we synthesize the evidence on the value of small protected habitat patches (SPHP) within production forest landscapes for biodiversity. Review question: Are small protected habitat patches within boreal production forests effective in conserving species richness, abunda…
Mechanisms of shrub encroachment into Northern Chihuahuan Desert grasslands and impacts of climate change investigated using a cellular automata model
2016
Arid and semiarid grasslands of southwestern North America have changed dramatically over the last 150 years as a result of woody plant encroachment. Overgrazing, reduced fire frequency, and climate change are known drivers of woody plant encroachment into grasslands. In this study, relatively sim- ple algorithms for encroachment factors (i.e., grazing, grassland fires, and seed dispersal by grazers) are proposed and implemented in the ecohydrological Cellular-Automata Tree Grass Shrub Simulator (CAT- GraSS). CATGraSS is used in a 7.3 km 2 rectangular domain located in central New Mexico along a zone of grassland to shrubland transition, where shrub encroachment is currently active. CATGraS…
Flexible timing of reproductive effort as an alternative mating tactic in black grouse (Lyrurus tetrix) males
2016
Alternative reproductive tactics often take the form of dichotomous behavioural phenotypes. Focusing attention on such obvious dichotomy means that flexible patterns of behaviour within tactics is largely ignored. Using a long-term dataset of black grouse (Lyrurus tetrix) lek behaviours, we tested whether there were fine-scale differences in reproductive effort (lek attendance, fighting rates) and whether these were related to age and phenotype. Yearling males increased their lek attendance and fighting rate to a peak when adult male effort was declining. Adults and yearlings allocated reproductive effort according to their body mass but this was unrelated to differences in timing of effort…
Could male tergal secretions be considered as a nuptial gift in the Madeira cockroach?
2008
International audience; Many male insects provide somatic nuptial gifts that may strongly influence reproductive fitness, ensuring effective copulation or mediating paternal resource benefits in offspring. Although the courtship feeding behaviour on tergal gland secretions has been described in numerous cockroaches, studies on the function of these so-called nuptial gifts are lacking in this group. In this study, we examined, in the Madeira cockroach, Leucophaea maderae, the functional significance of tergal secretions by manipulating their availability on the back of males. We tested whether male tergal secretions function as a form of mating effort, and/or as a form of paternal investment…
Calling behaviour of female Periplaneta americana: Behavioural analysis and identification of the pheromone source
1993
Abstract The site for the production of Periplanone B, one of the components of the female sex pheromone of Periplaneta americana , was localized in glands situated in the genital atrium, and we have called these structures atrial glands. While emitting the sex pheromone, females adopt a characteristic calling posture during which time the atrial glands are exposed. Behavioural assays of males utilizing pentane extracts of various female body parts revealed that atrial gland extracts are highly attractive, and induced more wing-raising behaviour, than any other female body part. GC-MS analyses support these results by revealing that Periplanone B is only present in the atrial glands. We est…
Permanent Genetic Resources added to Molecular Ecology Resources Database 1 December 2009-31 January 2010
2010
4 pages; International audience; This article documents the addition of 220 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Allanblackia floribunda, Amblyraja radiata, Bactrocera cucurbitae, Brachycaudus helichrysi, Calopogonium mucunoides, Dissodactylus primitivus, Elodea canadensis, Ephydatia fluviatilis, Galapaganus howdenae howdenae, Hoplostethus atlanticus, Ischnura elegans, Larimichthys polyactis, Opheodrys vernalis, Pelteobagrus fulvidraco, Phragmidium violaceum, Pistacia vera, and Thunnus thynnus. These loci were cross-tested on the following species: Allanblackia gabonensis, Allanblackia stanerana, Neoceratitis …
Social information use about novel aposematic prey is not influenced by a predator’s previous experience with toxins
2019
Aposematism is an effective antipredator strategy. However, the initial evolution and maintenance of aposematism are paradoxical because conspicuous prey are vulnerable to attack by naive predators. Consequently, the evolution of aposematic signal mimicry is also difficult to explain. The cost of conspicuousness can be reduced if predators learn about novel aposematic prey by observing another predator's response to that same prey. On the other hand, observing positive foraging events might also inform predators about the presence of undefended mimics, accelerating predation on both mimics and their defended models. It is currently unknown, however, how personal and social information combi…
Application of Selected Methods of Black Box for Modelling the Settleability Process in Wastewater Treatment Plant
2017
Abstract The paper described how the results of measurements of inflow wastewater temperature in the chamber, a degree of external and internal recirculation in the biological-mechanical wastewater treatment plant (WWTP) in Cedzyna near Kielce, Poland, were used to make predictions of settleability of activated sludge. Three methods, namely: multivariate adaptive regression splines (MARS), random forests (RF) and modified random forests (RF + SOM) were employed to compute activated sludge settleability. The results of analysis indicate that modified random forests demonstrate the best predictive abilities.