Search results for " Competition"
showing 10 items of 819 documents
Density‐dependent influence of male characters on mate‐locating efficiency and pairing success in the waterlouse Asellus aquaticus: an experimental s…
2005
Population density is likely to determine the form of competition in which males are engaged for access to females. At low density, scramble competition should be of paramount importance because of the low probability of encounter between males and females. Consequently, sexual selection should favour characters that allow rapid detection of females. Conversely, at high population density, sexual selection should favour attributes that raise the fighting ability of males because of the more frequent contacts between males. These general predictions were tested in this study for the precopulatory mate-guarding isopod, Asellus aquaticus. In this species, male-biased sexual dimorphisms are rep…
Interspecific extrinsic and intrinsic competitive interactions in egg parasitoids
2012
Interspecific competitive interactions can occur either between adult parasitoids searching/exploiting hosts (extrinsic competition) or between parasitoid larvae developing within the same host (intrinsic competition). Understanding how interspecific competition between parasitoids can affect pest suppression is important for improving biological pest control. The purpose of this work was to review both extrinsic and intrinsic competition between egg parasitoid species. These are organisms that are often candidates for biological control programs due to their ability to kill the pest before the crop feeding stage. We first reviewed the literature about interspecific competitive abilities of…
Morphological and molecular evidence for interspecific hybridisation in the introduced African genusCrassocephalum(Asteraceae: Senecioneae) in Asia
2009
Abstract The genus Crassocephalum in Asia, introduced there from Africa, was examined by extensive field work, herbarium studies, analyses of pollen and seed fertility, chromosome counts and ITS and trnL‐F sequencing. We found that Crassocephalum in Asia comprises two species and their interspecific hybrid. The two species are C. crepidioides (Benth.) S. Moore and C. rubens (Juss. ex Jacq.) S. Moore, of which the latter is a new record for Asia (north Thailand). The hybrid between these two species in north Thailand originated from a cross between C. crepidioides (2n = 40) as female and C. rubens (2n = 40) as male parent.
Molecular and Morphological Differentiation of Two Similar Species of Accacoeliidae (Digenea):Accacladocoelium macrocotyleandA. nigroflavumfrom Sunfi…
2014
In a study of 106 sunfish, Mola mola (L.), from Mediterranean waters, 2,731 worms, belonging to 2 congeneric species of accacoeliids, Accacladocoelium macrocotyle (Diesing, 1858) Robinson, 1934 and Accacladocoelium nigroflavum (Rudolphi, 1819) Robinson, 1934 , were collected from the digestive system. It is often difficult to differentiate between these 2 species as they are sympatric and very similar; in fact, according to previous descriptions, the extent of the vitellarium is the only interspecific difference, described as extending posteriorly to the ovary in A. macrocotyle and as anterior to the anterior testis in A. nigroflavum. However, this diagnostic trait is not always valid; more…
Contrasting effects ofWolbachiaon cytoplasmic incompatibility and fecundity in the haplodiploid miteTetranychus urticae
2002
Recent studies on Wolbachia-induced incompatibility in haplodiploid insects and mites have revealed a diversity of cytoplasmic incompatibility (CI) patterns among host species. Here, we report intraspecific diversity in CI expression among four strains of the arrhenotokous mite Tetranychus urticae and in T. turkestani. Variability of CI expression within T. urticae ranged from no CI to complete CI, and included either female embryonic mortality or male conversion types of CI. A fecundity cost attributed to the infection with the high-CI Wolbachia strain was the highest ever recorded for Wolbachia (−80 to −100% decrease). Sequence polymorphism at a 550-bp-portion of Wolbachia wsp gene reveal…
Agonistic and sociable behaviors in the mound-building mice,Mus spicilegus: A comparative study withMus musculus domesticus
2001
Present social organization and mating systems result from selective pressures and ecological conditions but also from proximate interactions between individuals. Many studies report on a polygynous mating system with a social group territoriality in commensal populations of Mus musculus domesticus. However, little is known about the social organization of other Mus species living in outdoor conditions, such as the mound-building mouse Mus spicilegus. Comparative studies between M. m. domesticus and M. spicilegus have already shown behavioral differences in female sexual preferences and paternal care. To study agonistic and sociable interactions and gain insight into the social organization…
The effect of periodic bottlenecks on the competitive ability of Drosophila pseudoobscura lines.
1993
Competition experiments between several Drosophila pseudoobscura strains that were previously subjected to periodic bottlenecks of different sizes and D. willistoni have been carried out. Contrary to previous results with these two species, where stable coexistence was detected, populations of D. pseudoobscura displaced D. willistoni in a few generations. By using a relative fitness measure, the control lines (that had not gone through bottlenecks) outcompeted D. willistoni faster than bottlenecked lines. One of these, corresponding to the minimum possible bottleneck size of one pair, also shows significantly lower relative fitness than the other strains. These results are discussed in rela…
Elezioni 2013: la crisi del "bipolarismo imperfetto" (ed. ampliata e aggiornata)
2015
Questo articolo analizza l'interazione tra sistema elettorale e sistema partitico nel caso italiano confrontando i risultati delle elezioni politiche nel 2006, 2008 e 2013. A partire dall'osservazione dei diversi risultati delle elezioni politiche del 2006 e del 2008, da un lato, e del 2013, dall'altro, l’articolo dedica attenzione a come tra i sistemi elettorali e di partito non vi sia un nesso causale sistematico, ma una "interazione di reciproca indipendenza". Le prime due elezioni politiche, svoltesi in base alla legge elettorale del 2005, hanno portato a un mantenimento del sistema bipolare. Il terzo, al contrario, ha portato a un ripristino del sistema multipolare. Tali risultati dive…
Incentive Mechanism for Edge-Computing-Based Blockchain
2020
Blockchain has been gradually applied to different Internet of Things (IoT) platforms. As the efficiency of the blockchain mainly depends on the network computing capability, how to make sure the acquisition of the computational resources and participation of the devices would be the driving force. In this work, we focus on investigating incentive mechanism for rational miners to purchase the computational resources. A edge computing-based blockchain network is considered, where the edge service provider (ESP) can provide computational resources for the miners. Accordingly, we formulate a two-stage Stackelberg game between the miners and ESP. The aim is to investigate Stackelberg equilibriu…
<em>El dibujado</em>: volver a la pared
2021
The exhibition El dibujado by Paco Roca (IVAM, 2019) is an exploration of the paradigm shift brought forth by the abandonment of paper and reproducibility as a space for the dissemination of the comic strip. The exhibition hall of a museum (the Instituto Valenciano de Arte Moderno) becomes a space for formal and ephemeral experimentation at different levels, from the purely creative to the pondering about the unexplored possibilities of the language of the comic book. With this exhibition cartoonist Paco Roca poses a challenge to a spectator who is called to leave his/her role as a visitor and become the reader of an experience in which s/he becomes a part of the work’s own narrative. The a…