Search results for "quotation"
showing 10 items of 18815 documents
Effects of multiple stressors on the dimensionality of ecological stability
2021
Abstract Ecological stability is a multidimensional construct. Investigating multiple stability dimensions is key to understand how ecosystems respond to disturbance. Here, we evaluated the single and combined effects of common agricultural stressors (insecticide, herbicide and nutrients) on four dimensions of stability (resistance, resilience, recovery and invariability) and on the overall dimensionality of stability (DS) using the results of a freshwater mesocosm experiment. Functional recovery and resilience to pesticides were enhanced in nutrient‐enriched systems, whereas compositional recovery was generally not achieved. Pesticides did not affect compositional DS, whereas functional DS…
Extended haplodiploidy hypothesis
2019
P.R., M.P., and H.H. were supported by Academy of Finland (grant 258385 to M.P., grant 135970 to H.H., and 252411 to the Centre of Excellence in Biological Interactions), P.R. also by the Royal Society Newton International Fellowship, and H.H. also by the Kone Foundation. Evolution of altruistic behavior was a hurdle for the logic of Darwinian evolution. Soon after Hamilton formalized the concept of inclusive fitness, which explains how altruism can evolve, he suggested that the high sororal relatedness brought by haplodiploidy could be why Hymenopterans have a high prevalence in eusocial species, and why helpers in Hymenoptera are always female. Later it was noted that in order to capitali…
A possible link between parasite defence and residual reproduction
2007
Life-history theory centres around trade-offs between current and future reproduction, but we have little understanding of how such trade-offs are mediated. We supplementary fed Ural owls (Strix uralensis) during the nestling period and quantified parents' current and future life-history components as well as their physiological health by monitoring haematocrit, leucocyte profile, intra- and extracellular blood parasites. Feeding led to reduced parental effort but did not improve offspring viability, male parasite defence, or parental survival. Intracellular leucocytozoan infection was reduced in fed females which lasted to the following year's reproductive season (carry-over effect), when …
Male health status, signalled by courtship display, reveals ejaculate quality and hatching success in a lekking species.
2010
8 pages; International audience; Summary 1. The information content of secondary sexual traits and the benefits gathered by choosy females are at the heart of sexual selection theory. Indicator models of sexual selection assume that secondary sexual traits reflect the phenotypic/genetic quality of their bearers and that females gather benefits from choosing these high-quality males. 2. Here, we tested the idea that courtship display reflects the health status in a bird species with a lek-based mating system, the houbara bustard (Chlamydotis undulata undulata). A group of males was treated with the lipopolysaccharide (LPS) of the cell wall of the bacterium Escherichia coli during the seasona…
The Bruce effect revisited: is pregnancy termination in female rodents an adaptation to ensure breeding success after male turnover in low densities?
2017
Pregnancy termination after encountering a strange male, the Bruce effect, is regarded as a counterstrategy of female mammals towards anticipated infanticide. While confirmed in caged rodent pairs, no verification for the Bruce effect existed from experimental field populations of small rodents. We suggest that the effect may be adaptive for breeding rodent females only under specific conditions related to populations with cyclically fluctuating densities. We investigated the occurrence of delay in birth date after experimental turnover of the breeding male under different population composition in bank voles (Myodes glareolus) in large outdoor enclosures: one-male–multiple-females (n = 6 p…
Sex-specific variation in the onset of reproduction and reproductive trade-offs in a boreal small mammal
2014
In seasonal environments, the optimal onset of reproduction plays a major role in defining the reproductive success of an individual. Environmental cues, like day length, weather conditions, and food, regulate the initiation and termination of the breeding season. Besides the interspecific variation in response to environmental cues, it has been suggested that due to different selection pressures, females and males can have different responses to environmental stimuli. However, this phenomenon has gained relatively little consideration, and the physiological mechanism behind these differences is not well known. Here, we report how two different environmental cues, variability of temperature…
Evolutionary conservation advice for despotic populations: habitat heterogeneity favours conflict and reduces productivity in Seychelles magpie robins
2010
Individual preferences for good habitat are often thought to have a beneficial stabilizing effect for populations. However, if individuals preferentially compete for better-quality territories, these may become hotspots of conflict. We show that, in an endangered species, this process decreases the productivity of favoured territories to the extent that differences in productivity between territories disappear. Unlike predictions from current demographic theory on site-dependent population regulation (ideal despotic distribution), we show that population productivity is reduced if resources are distributed unevenly in space. Competition for high-quality habitat can thus have detrimental con…
Effect of ozone treatment on the microstructure, chemical composition and sensory quality of apple fruits
2018
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research commissioned by Agricultural services co-operative society ‘AUGL¸ NAMS’ has been conducted within framework ‘The research of fruit storage technologies’ funded by State program ‘Competence Centre for Food in Latvia’.
Coupling transcriptomics and behaviour to unveil the olfactory system of Spodoptera exigua larvae
2020
AbstractChemoreception in insects is crucial for many aspects related to food seeking, enemy avoidance, and reproduction. Different families of receptors and binding proteins interact with chemical stimuli, including odorant receptors (ORs), ionotropic receptors (IRs), gustatory receptors (GRs), odorant binding proteins (OBPs) and chemosensory proteins (CSPs). In this work, we describe the chemosensory-related gene repertoire of the worldwide spread pest Spodoptera exigua (Lepidoptera: Noctuide) focusing on the transcripts expressed in larvae, which feed on many horticultural crops producing yield losses. A comprehensive de novo assembly that includes reads from chemosensory organs of larva…
Introducing water frogs - Is there a risk for indigenous species in France?
2007
The ecological success of introduced species in their new environments is difficult to predict. Recently, the water frog species Rana ridibunda has raised interest, as different genetic lineages were introduced to various European countries. The aim of the present study was to analyze the potential invasiveness of R. ridibunda and assess the risk of replacement for indigenous water frog species. The investigation of over 700 water frogs from 22 locations in southern France and four locations in Spain shows that the competition with indigenous species is mainly limited to a particular habitat type, characterized by high-oxygen and low-salinity freshwater. The competitive strength of R. ridib…