Search results for "Formes"
showing 10 items of 309 documents
Life-history differences in age-dependent expressions of multiple ornaments and behaviors in a lekking bird
2015
Age is a major factor explaining variation in life-history traits among individuals with typical patterns of increasing trait values early in life, maximum trait expression, and senescence. However, age-dependent variation in the expressions of sexually selected traits has received less attention, although such variation underpins differences in male competitive abilities and female preference, which are central to sexual selection. In contrast to previous studies focusing on single traits, we used repeated measures of seven sexually selected morphological and behavioral traits in male black grouse (Tetrao tetrix) to quantify the effects of age and life span on their expressions and quantif…
Simultaneous age‐dependent and age‐independent sexual selection in the lekking black grouse(Lyrurus tetrix)
2014
Individuals' reproductive success is often strongly associated with their age, with typical patterns of early‐life reproductive improvement and late‐life senescence. These age‐related patterns are due to the inherent trade‐offs between life‐history traits competing for a limited amount of resources available to the organisms. In males, such trade‐offs are exacerbated by the resource requirements associated with the expression of costly sexual traits, leading to dynamic changes in trait expression throughout their life span. Due to the age dependency of male phenotypes, the relationship between the expression of male traits and mating success can also vary with male age. Hence, using longitu…
New behavioural trait adopted or rejected by observing heterospecific tutor fitness
2010
Animals can acquire behaviours from others, including heterospecifics, but should be discriminating in when and whom to copy. Successful individuals should be preferred as tutors, while adopting traits of poorly performing individuals should be actively avoided. Thus far it is unknown if such adaptive strategies are involved when individuals copy other species. Furthermore, rejection of traits based on tutor characteristics (negative bias) has not been shown in any non-human animal. Here we test whether a choice between two new, neutral behavioural alternatives—breeding-sites with alternative geometric symbols—is affected by observing the choice and fitness of a heterospecific tutor. A fiel…
Reversible stress softening of collagen based networks from the jumbo squid mantle (Dosidicus gigas).
2014
Dosidicus gigas is the largest and one of the most abundant jumbo squids in the eastern Pacific Ocean. In this paper we have studied the muscle of the mantle of D. gigas (DGM). Morphological, thermal and rheological properties were assessed by means of atomic force microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, thermogravimetry and oscillatory rheometry. This study allowed us to assess the morphological and rheological properties of a collagen based network occurring in nature. The results showed that the DGM network displays a nonlinear effect called reversible stress softening (RSS) that has been previously described for …
I traffici illeciti nel Mediterraneo. Persone, stupefacenti, tabacco
2019
Attraverso la combinazione di ricerca criminologica e giuridico-normativa, e grazie anche alla collaborazione con esperti esterni (studiosi, magistrati, rappresentanti di istituzioni italiane e straniere), la ricerca da cui scaturisce il volume ha indagato le interazioni tra i diversi traffici illeciti e la criminalità organizzata nel bacino del Mediterraneo. In tale area, storicamente cruciale per la mobilità di persone e di beni, l’attenzione si è rivolta in particolare ai fenomeni del traffico e della tratta di persone, del traffico di stupefacenti e del contrabbando di sigarette. I contributi raccolti – unitamente al rapporto criminologico e ai cinque rapporti nazionali accessibili su w…
Climate driven life histories: the case of the Mediterranean Storm petrel
2014
Seabirds are affected by changes in the marine ecosystem. The influence of climatic factors on marine food webs can be reflected in long-term seabird population changes. We modelled the survival and recruitment of the Mediterranean storm petrel (Hydrobates pelagicus melitensis) using a 21-year mark-recapture dataset involving almost 5000 birds. We demonstrated a strong influence of prebreeding climatic conditions on recruitment age and of rainfall and breeding period conditions on juvenile survival. The results suggest that the juvenile survival rate of the Mediterranean subspecies may not be negatively affected by the predicted features of climate change, i.e., warmer summers and lower rai…
Effects of Nautical Traffic and Noise on Foraging Patterns of Mediterranean Damselfish (Chromis chromes)
2012
Chromis chromis is a key species in the Mediterranean marine coastal ecosystems where, in summer, recreational boating and its associated noise overlap. Anthropogenic noise could induce behavioural modifications in marine organisms, thereby affecting population dynamics. In the case of an important species for the ecosystem like C. chromis, this could rebound on the community structure. Here, we measured nautical traffic during the summer of 2007 in a Southern Mediterranean Marine Protected Area (MPA) and simultaneously the feeding behaviour of C. chromis was video-recorded, within both the no-take A-zone and the B-zone where recreational use is allowed. Feeding frequencies, escape reaction…
Overlapping patterns of morphometric and genetic differentiation in the Mediterranean goby Pomatoschistus tortonesei Miller, 1968 (Perciformes, Gobii…
2012
Abstract. The genetic and morphological variations of Pomatoschistus tortonesei Miller, 1968 were studied in samples collected from three Tunisian lagoons. The morphological analysis included 18 morphometric measurements and was based on linear discriminant analysis (LDA), whereas the genetic analysis was based on the 16S-rRNA and COI mitochondrial genes. Both analyses differentiated the populations and demonstrated consistently a well-supported differentiation between the western Mediterranean samples (Bizerta and Tunis South lagoons) and the eastern Mediterranean sample (El Bibane lagoon). The observed differentiation could be explained in terms of the geographic isolation of the various …
Seasonal trend of Anisakidae infestation in South Mediterranean bluefish
2020
A total of 1104 fish samples from markets of Sicily were analysed for the detection and species identification of Anisakidae nematodes. The preliminary analysis of the fish samples showed the presence of 2459 larvae. All the fish species revealed different prevalence of infestation, with a maximum of 100% for Lepidopus caudatus and a minimum of 4.5% in Sardina pilchardus. The 80% of the larvae examined by PCR-RFLP analysis belonged to Anisakis pegreffii species. The seasonal infestation trend of Anisakis was evaluated in all the fish sample examined. The results of the seasonal infestation trend showed a marked connection with the ecological aspects of the fish species examined. As far as w…
A new cystidicolid nematode from Mullus surmuletus (Perciformes: Mullidae) from the western Mediterranean.
2005
Ascarophis valentina n. sp. is described from Mullus surmuletus off the Valencian coast of Spain on the basis of both light and scanning electron microscopy. It can be distinguished from the other members of the genus by the length of the left (long) spicule of the males and by egg morphology. An updated grouping of the species of Ascarophis considered valid is provided with respect to these characters. The new species resembles Ascarophis capelanus, belonging to the group of species possessing eggs with a single polar knob with filaments, but is distinguished by the size of the body, the length of the esophagus (especially in relation to body length), the position of the vulva, and the siz…