Search results for "Asellus aquaticus"
showing 6 items of 16 documents
Quantification of sexual dimorphism in Asellus aquaticus (Crustacea: Isopoda) using outline approaches
2002
A marked sexual dimorphism is often observed in arthropods species in which males perform precopulatory mate guarding. It is generally thought to reflect the influence of sexual selection. Until now, sexual dimorphisms associated with mate guarding have mainly been qualitatively described. However, assessing the effects of sexual selection on sexual dimorphims requires a preliminary quantitative assessment of differences in morphology between sexes. Using Fourier analyses, we tested if morphological dimorphisms could be quantitatively assessed in the isopod Asellus aquaticus. In addition, we checked whether sexual dimorphism in shape was exclusively related to mate guarding through consider…
Multidimensionality and intra-individual variation in host manipulation by an acanthocephalan
2008
Parasitology, 135 (5)
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…
Differences in parasite susceptibility and costs of resistance between naturally exposed and unexposed host populations
2009
It is generally assumed that resistance to parasitism entails costs. Consequently, hosts evolving in the absence of parasites are predicted to invest less in costly resistance mechanisms than hosts consistently exposed to parasites. This prediction has, however, rarely been tested in natural populations. We studied the susceptibility of three naïve, three parasitized and one recently isolated Asellus aquaticus isopod populations to an acanthocephalan parasite. We found that parasitized populations, with the exception of the isopod population sympatric with the parasite strain used, were less susceptible to the parasite than the naïve populations. Exposed but uninfected (resistant) isopods f…
Isopoda Asellota de Turquie récoltés en 1987
1996
Asellus aquaticus is present in 19 of about 100 Turkish groundwater stations prospected during biospeleological explorations. All specimens of these stygophilic populations remain oculate, even though their integumental pigmentation is more or less reduced. Proasellus lykaonicus Argano & Pesce, 1978 has been found again in a second cave, nearby the type locality. A large and endemic, stygobiont species, Proasellus pisidicus n. sp., from phreatic groundwater, Vilâyet Burdur, and the minute Proasellus pamphylicus n. sp. from interstitial waters of the eastern part of Vilâyet Antalya are described. The stygobiont proasellids of Asia Minor, P. lykaonicus and P. pisidicus n. sp. belong to the sa…