Search results for "selection"

Behavioral responses of the parasitoid Melittobia digitata to volatiles emitted by its natural and laboratory hosts

2010

Responses of macropterous females of the ectoparasitoid Melittobia digitata Dahms (Hymenoptera: Eulophidae) to direct and indirect cues emitted by its natural hosts as well as laboratory hosts were investigated using a Y-tube olfactometer. To locate the nest ofmud dauber wasps, Trypoxylon politum Say (Hymenoptera: Crabronidae), and one of their inquilines, Anthrax spec., parasitoids exploit volatiles from the freshly built nest mud and the empty cocoon constructed by the wasps, as well as their meconium. However, the parasitoids did not respond to odors emitted by older nest mud or by the host stages that are attacked (T. politum prepupae and Anthrax spec. larvae). Melittobia digitata was n…

Exploring genome-wide differentiation and signatures of selection in Italian and North American Holstein populations

2023

Among Italian dairy cattle, the Holstein is the most reared breed for the production of Parmigiano Reggiano protected designation of origin cheese, which represents one of the most renowned products in the entire Italian dairy industry. In this work, we used a medium-density genome-wide data set consisting of 79,464 imputed SNPs to study the genetic structure of Italian Holstein breed, including the population reared in the area of Parmigiano Reggiano cheese production, and assessing its distinctiveness from the North American population. Multidimensional scaling and ADMIXTURE approaches were used to explore the genetic structure among populations. We also investigated putative genomic regi…

Detection of genomic signatures of selection in the North African Brune de l’Atlas cattle

2018

The identification of signatures of selection in indigenous livestock genome is able to elucidate the adaptive mechanisms allowing them to cope with environmental pressures. In the present study, we used genotyping data from 106 Brune de l’Atlas cattle individuals and tests based on the extent of haplotype homozygosity (EHH) to look for footprints of natural selection. We identified 17 genomic regions displaying strong signal of selection (p-value <10-6) overlapping with previously described QTL regions affecting many traits such as meat and milk composition, tuberculosis susceptibility, tick and mastitis resistance. Some of these highly significant candidate regions overlap with four previ…

Selection signatures of fat tail in sheep

2017

The investigation of the genes with a role in lipid metabolism enjoy considerable scientific and commercial interest because of the strong correlations between fat deposition and the risk of cardiovascular disease. The fat tail characteristic of sheep is the adaptive response to harsh environment, and beyond representing a valuable energy reserve for facing future climate changes provides clues for elucidating the physiology of fat deposition. Studies on various sheep populations detected fat-tail signatures on chromosomes 2, 3, 5, 6, 7 and 13. Fat-tailed sheep represent about 25% of the world’s sheep population, and the genes with a role in this phenotype are likely not the same for every …

Evolution and functional differentiation of recently diverged phytochelatin synthase genes from Arundo donax L.

2019

Plant phytochelatin synthases undergo evolutionarily rapid functional differentiation after duplication, allowing fast and precise adjustment of metal detoxification capacity by modulation of both transcription and enzymatic activity.

Avian brood parasitism in the new and old worlds

Nest attendance, extended phenotype and social selection in multispecies colonies

2017

Colonial species interact not only with conspecifics but often with other species nesting in the same site. The effect of conspecific traits have been measured recently with a multilevel selection analysis, but the effect of social traits of heterospecifics on individual fitness remain unquantified. We recorded nest attendance effort of two species, lesser kestrels (Falco naumanni) and jackdaws (Corvus monedula), nesting on the Gela Plain (Sicily, Italy). Both species are secondary-cavity nesters breeding in abandoned rural buildings where they form single-species or mixed-species colonies. By correlating reproductive success as a measure of fitness to conspecific and heterospecific nest at…

Scuba diver behaviour and its effects on the biota of a Mediterranean marine protected area

2009

The effects of diving activity in different Mediterranean subtidal habitats are scarcely known. This study evaluates diver behaviour (for example time spent in each habitat), use (contacts made with the substrate) and immediate effects of diver contact on benthic species in a marine protected area (MPA) in Sicily. Over a two-year period, intentions of 105 divers were observed within seven subtidal habitats: algae on horizontal substrate, algae on vertical substrate, Posidonia oceanica, encrusted walls, caves, sand and pebbles. Divers selected a habitat in proportion to its availability along the scuba trail. On average, each diver made 2.52 contacts every seven minutes, and no differences w…

Feeding preferences of Paracentrotus lividus exposed to native and non-native macroalgae

2016

The effects of alien macroalgal invasions on ecosystem functioning may depend on the feeding choice of native herbivores between native and non-native algae. The co-occurrence of two invasive Caulerpa species, C. taxifolia var. distichophylla and C. cylindracea in Southern Sicily, offered the possibility to investigate the feeding preferences of a generalist native grazer, the sea urchin Paracentrotus lividus, for native vs non-native food. A multiple choice feeding experiment was set to assess whether and to which extent P. lividus consumes the exotic macroalgae while in presence of the preferred native ones. Multiple choice feeding assays were run with the following food sources simultane…

Do island plant populations really have lower genetic variation than mainland populations? Effects of selection and distribution range on genetic div…

2015

Ecological and evolutionary studies largely assume that island populations display low levels of neutral genetic variation. However, this notion has only been formally tested in a few cases involving plant taxa, and the confounding effect of selection on genetic diversity (GD) estimates based on putatively neutral markers has typically been overlooked. Here, we generated nuclear microsatellite and plastid DNA sequence data in Periploca laevigata, a plant taxon with an island–mainland distribution area, to (i) investigate whether selection affects GD estimates of populations across contrasting habitats; and (ii) test the long-standing idea that island populations have lower GD than their mai…