Search results for "PPI"
showing 10 items of 7396 documents
Harvest‐induced evolution and effective population size
2016
Much has been written about fishery-induced evolution (FIE) in exploited species, but relatively little attention has been paid to the consequences for one of the most important parameters in evolutionary biology-effective population size (N-e). We use a combination of simulations of Atlantic cod populations experiencing harvest, artificial manipulation of cod life tables, and analytical methods to explore how adding harvest to natural mortality affects N-e, census size (N), and the ratio N-e/N. We show that harvest-mediated reductions in N-e are due entirely to reductions in recruitment, because increasing adult mortality actually increases the N-e/N ratio. This means that proportional red…
The effects of data collection and observation methods on uncertainty of social networks in wild primates
2020
International audience; In social species, network centralities of group members shape social transmission and other social phenomena. Different factors have been found to influence the measurement of social networks, such as data collection and observation methods. In this study, we collected data on adults and juveniles and examined the effect of data collection method (ad libitum sampling vs. focal animal sampling) and observation method (interaction—grooming; play—vs. association—arm‐length; 2 m; 5 m proximities—) on social networks in wild vervet monkeys. First, we showed using a bootstrapping method, that uncertainty of ad libitum grooming and play matrices were lesser than uncertaint…
World-wide variation in Drosophila melanogaster sex pheromone: behavioural effects, genetic bases and potential evolutionary consequences
1996
0016-6707 (Print) Journal Article Research Support, Non-U.S. Gov't; In Drosophila melanogaster, male wing vibration, a key element of courtship behaviour, is most efficiently induced by a female-specific contact pheromone cis, cis 7,11 heptacosadiene (7,11 HD), which is the main mature female cuticular hydrocarbon in the CS laboratory strain. A study of 63 strains from around the world revealed that flies from Sub-Saharan Africa and the Caribbean are unique in showing low levels 7,11 HD and high levels of the position isomer 5,9 HD. This difference maps to chromosome III, perhaps indicating a simple genetic control of the 7,11 HD:5,9 HD ratio. Females from strains with high levels of 7,11 H…
Elevated oxidative stress in pied flycatcher nestlings of eumelanic foster fathers under low rearing temperatures
2019
Striking variation in melanin coloration within natural populations is likely due to the different fitness outcomes of alternative phenotypes in varying environmental conditions. There are two types of melanin: eumelanins yield blackish hues, whereas pheomelanins yield reddish hues. The production of eumelanins requires low levels of glutathione (GSH), which is the most important intracellular antioxidant, whereas the production of pheomelanins requires high levels of GSH. We investigated the oxidative status of male pied flycatchers (Ficedula hypoleuca) with different degrees of melanin coloration under different temperatures during the nestling period. Moreover, we assessed the oxidative …
Diet and trophic niche of the invasive signal crayfish in the first invaded Italian stream ecosystem.
2021
The occurrence of the signal crayfsh Pacifastacus leniusculus in the Valla Stream was the frst established population of this invasive species recorded in an Italian stream ecosystem. We evaluated the seasonality of diet and trophic niche of invasive signal crayfsh in order to estimate the ecological role and efects on native communities of the stream ecosystem. We studied the diferences in food source use between sexes, life stages and seasons using carbon and nitrogen stable isotope analyses. To supplement stable isotope analyses, we evaluated food source usage using traditional stomach content analysis. We tested the hypothesis that juveniles have a diferent diet, showing diferent trophi…
Cultivating for the Industry: Cropping Experiences with Hypericum perforatum L. in a Mediterranean Environment
2021
Hypericum perforatum is an intensively studied medicinal plant, and much experimental activity has been addressed to evaluate its bio-agronomical and phytochemical features as far. In most cases, plant material used for experimental purposes is obtained from wild populations or, alternatively, from individuals grown in vases and/or pots. When Hypericum is addressed to industrial purposes, the most convenient option for achieving satisfactory amounts of plant biomass is field cultivation. Pot cultivation and open field condition, however, are likely to induce different responses on plant’s metabolism, and the obtained yield and composition are not necessarily the same. To compare these manag…
Differences in the growth cycle ofRuppia cirrhosa(Petagna) Grande in a Mediterranean shallow system
2014
Ruppia cirrhosa growth cycle was analysed in a southern Mediterranean shallow system throughout 1 year. We examined the temporal variation in R. cirrhosa cover percentage, shoot density, biomass, leaf length, no. flowers m-2 and no. fruits m-2 in two groups of pond characterized by differences in some environmental parameters. Ponds were comparable for salinity and temperature but they differed for other environmental parameters such as water depth, level of suspended organic matter and chlorophyll a (CHL a). Biological parameter values were higher in B ponds, characterized by lower values of water depth, suspended organic matter and CHL a. A seasonal trend for all considered biological par…
Agro-ecological benefits of faba bean for rainfed Mediterranean cropping systems
2017
This paper reviews the main results from a set of experiments carried out in a semiarid Mediterranean environment during the past 25 years on faba bean (<em>Vicia faba</em> L.), a crop traditionally grown in southern Italy and Sicily under rainfed conditions. These experiments focused on the residual effects of faba bean on subsequent crop(s) and assessment of the nitrogen (N) balance during the crop cycle, paying attention to both the environmental release of N (losses via volatilisation and denitrification) and estimates of N2 fixation as influenced by tillage system, intercropping, and presence/absence of mycorrhizal inoculum. Faba bean relied on N2 fixation more than other g…
Rhizosphere Bacterial Networks, but Not Diversity, Are Impacted by Pea-Wheat Intercropping
2021
International audience; Plant-plant associations, notably cereal-legume intercropping, have been proposed in agroecology to better value resources and thus reduce the use of chemical inputs in agriculture. Wheat-pea intercropping allows to decreasing the use of nitrogen fertilization through ecological processes such as niche complementarity and facilitation. Rhizosphere microbial communities may account for these processes, since they play a major role in biogeochemical cycles and impact plant nutrition. Still, knowledge on the effect of intecropping on the rhizosphere microbiota remains scarce. Especially, it is an open question whether rhizosphere microbial communities in cereal-legume i…
Transcriptome and proteome analysis of Pinctada margaritifera calcifying mantle and shell: focus on biomineralization
2010
Abstract Background The shell of the pearl-producing bivalve Pinctada margaritifera is composed of an organic cell-free matrix that plays a key role in the dynamic process of biologically-controlled biomineralization. In order to increase genomic resources and identify shell matrix proteins implicated in biomineralization in P. margaritifera, high-throughput Expressed Sequence Tag (EST) pyrosequencing was undertaken on the calcifying mantle, combined with a proteomic analysis of the shell. Results We report the functional analysis of 276 738 sequences, leading to the constitution of an unprecedented catalog of 82 P. margaritifera biomineralization-related mantle protein sequences. Component…