Search results for "evolution"
showing 10 items of 11096 documents
Infanticide and Population Growth in the Bank Vole (Myodes glareolus): The Effect of Male Turnover and Density
2011
One major intrinsic factor affecting recruitment of young into a population is infanticide, the killing of conspecific young by adult males. It occurs in most mammal species, like our study species the bank vole (Myodes glareolus), and is widely accepted as an adaptive behavior, which may increase male fitness via nutritional gain, decreased competition, or an increased access to mates. A turnover of males in a population increases the risk of infanticide owing to a disruption of social structures. In a controlled field study, we tested the effects of total male turnover and density on juvenile recruitment and female space use in experimental bank vole populations. Juvenile recruitment decl…
Differences in gene flow in a twofold secondary contact zone of pond turtles in southern Italy (Testudines: Emydidae:Emys orbicularis galloitalica,E.…
2015
Using virtually range-wide sampling for three pond turtle taxa (Emys orbicularis galloitalica, E. o. hellenica, E. trinacris), we analyse gene flow across their southern Italian contact zone. Based on population genetic analyses of 15 highly polymorphic microsatellite loci and a mitochondrial marker, we show that the general genetic pattern matches well with the current taxon delimitation. Yet, single individuals with conflicting genetic identity suggest translocation of turtles by humans. In addition, we identify in south-western France and the vicinity of Rome populations being heavily impacted by introduced turtles. Cline analyses reveal that the major genetic break between E. o. galloit…
Genetic variability and evolutionary dynamics of tomato black ring virus population
2021
Tomato black ring virus (TBRV) is an important pathogen infecting a wide range of plant species worldwide. Phylogenetic studies of TBRV have already been conducted, although limited by the use of short genomic regions or a reduced amount of isolates. In the present study, we carried out an exhaustive phylogenetic and population genetic analysis based on the coat protein gene (CP) sequence of 57 TBRV isolates originating from different host plants and European geographic regions (47 isolates from Poland, 8 from Lithuania, one from the UK, and one from Hungary). Moreover, the selective pressure acting on particular codons and coevolution of amino acid residues in the CP were analysed. The res…
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…
Brassica trichocarpa (Brassicaceae), a new species from Sicily
2013
A new species of Brassica from Sicily, namely B. trichocarpa, is described and illustrated. This suffrutex was found on a calcareous peak of a mount near Palermo, where it is represented by a single population occupying a really small surface. It is well differentiated from the other perennial species belonging to B. sect. Brassica mainly in having hairy ovary and very short, thickened, hairy, not torulose fruits. Its relationships and taxonomical position within this group are examined too. An analytical key of the current taxa belonging to the genus Brassica sect. Brassica is also provided.
Responses in metabolic rate to changes in temperature in diapausing Colorado potato beetleLeptinotarsa decemlineatafrom three European populations
2015
Many insects survive adverse periods in seasonal environments by entering diapause, a deep resting stage, during which energy consumption is typically low and gas exchange is in the form of a discontinuous gas exchange cycle (DGC). Because insects in high-latitude environments are severely time constrained during summer, an effective diapause termination with careful regulation of metabolic rate is important. The present study examines whether diapausing Colorado potato beetles Leptinotarsa decemlineataSay originating from three latitudinally different regions in Europe differ in their quantitative or qualitative gas exchange patterns in response to an increasing temperature. Overall produc…
Genetic differentiation of three species of Matthiola (Brassicaceae) in the Sicilian insular system
2005
We examined the genetic variation of 12 isozyme loci in 14 populations of Matthiola (Brassicaceae) representing the geographic distribution of the species M. incana, M. fruticulosa ssp. fruticulosa and M. tricuspidata in the Sicilian insular system and the adjacent mainland areas to estimate the levels and apportionment of genetic variation in the insular populations and to understand their population dynamics. The disparity in the distribution of polymorphism in populations of M. incana ssp. incana (low within populations but with high values of F ST and G ST ) contrasts with the homogeneity in the inter-population distribution of the high genetic variation detected in M. tricuspidata and …
Parasitic infracommunities of the Aegean wall lizard Podarcis erhardii (Lacertidae, Sauria): isolation and impoverishment in small island populations
2009
AbstractThe Aegean wall lizard Podarcis erhardii, is widely distributed across the islands of the Aegean Sea (Greece). While there exists a relatively substantial body of knowledge on the ecology and life history of the species, the parasite communities of the taxon remain almost completely unknown. Quantifying the composition of these communities in P. erhardii is not only important for autoecological reasons, but also because inter-island comparisons of this lizard's parasite communities can shed light on the factors that structure parasite diversity in general. Here we investigate the gastrointestinal parasite communities of P. erhardii populations occurring on 16 landbridge islands of t…
Spatial ecology of coastal Atlantic cod Gadus morhua associated with parasite load
2015
Acoustic tags and receivers were used to investigate the spatial ecology of coastal Atlantic cod Gadus morhua (n = 32, mean fork length: 50 cm, range: 33–80 cm) on the Norwegian Skagerrak coast in 2012. Monthly home ranges (HR), swimming activity and depth use varied considerably among individuals and through the months of June, July and August. HR sizes for the period ranged from 0·25 to 5·20 km2 (mean = 2·30 km2). Two thirds of the tagged G. morhua were infected with black spot disease Cryptocotyle lingua parasites; these fish had larger HRs and occupied deeper water compared with non-infected fish. The infected fish also tended to be more active in terms of horizontal swimming. From an e…
Breeding strategy and morphological characters in an urban population of blackbirds, Turdus merula
2001
Pairing patterns in monogamous birds are thought to be the consequence of mutual mate choice by males and females for characters linked to individual quality in the opposite sex. Although this may result in assortative pairing for a single character, there may be no simple match between male and female phenotype if the traits linked to individual quality are sex specific. For instance, in several passerine species, females tend to select males on the basis of territory quality or characters that may reflect health or vigour, whereas males benefit from pairing with females in good condition that breed early because early breeding increases reproductive success. We investigated pairing patter…