Search results for "riforme"
showing 10 items of 87 documents
Testosterone and oxidative stress: the oxidation handicap hypothesis
2007
Secondary sexual traits (SST) are usually thought to have evolved as honest signals of individual quality during mate choice. Honesty of SST is guaranteed by the cost of producing/maintaining them. In males, the expression of many SST is testosterone-dependent. The immunocompetence handicap hypothesis has been proposed as a possible mechanism ensuring honesty of SST on the basis that testosterone, in addition to its effect on sexual signals, also has an immunosuppressive effect. The immunocompetence handicap hypothesis has received mixed support. However, the cost of testosterone-based signalling is not limited to immunosuppression and might involve other physiological functions such as the…
Sex-specific differences in offspring personalities across the laying order in magpies Pica pica
2013
Maternal effects provide an important mechanism for mothers to create variation in offspring personality, and to potentially influence offspring life history strategies e.g. creating more/less dispersive phenotypes. However, within-clutch maternal effects often vary and hence there is potential for within-clutch variation in personality. We studied the effects of hatching order on explorative and neophobic behaviour of the magpies Pica pica in relation to sex using novel environment and novel object experiments. Hatching order did affect explorative behaviour in magpie, but did so in opposite directions for either sex. First-hatched females were more explorative and had a tendency to be les…
Translocation as a novel approach to study effects of a new breeding habitat on reproductive output in wild birds
2011
Environmental conditions under which species reproduce have major consequences on breeding success and subsequent fitness. Therefore breeding habitat choice is ultimately important. Studies rarely address the potential fitness pay-offs of alternative natural breeding habitats by experimental translocation. Here we present a new tool to study fitness consequences of free living birds in different habitats. We translocated a migratory passerine, the pied flycatcher (Ficedula hypoleuca), to a novel site, where pairs were subjected to a short stay (2-4 days) in a nest box-equipped aviary before being released. We show that it is technically possible to retain birds in the new area for breeding,…
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…
Occurrence of two rare species from order Lampriformes: Crestfish Lophotus lacepede (Giorna, 1809) and scalloped ribbonfish Zu cristatus(Bonelli, 181…
2017
The bony fish Lophotus lacepede (Giorna, 1809) and Zu cristatus (Bonelli, 1819) are the two species rarely recorded within the Mediterranean basin, usually reported as accidentally captured in depth (mesopelagic) fishing operations. In the current work, we present the first record of L. lacepede and Z. cristatus in fishing catches from southwestern Tyrrhenian Sea. Moreover, in order to improve existent biological/ ecological knowledge, some bio-related aspects such as feeding aspect, sexual maturity and age estimate have been discussed.
La riforma del sistema penale secondo la Commissione Lattanzi
2021
L'articolo approfondisce le riforme al sistema penale ipotizzate dalla Commissione Lattanzi, nominata dal Ministro della Giustizia Cartabia.
Repeatability of Feather Mite Prevalence and Intensity in Passerine Birds
2014
Understanding why host species differ so much in symbiont loads and how this depends on ecological host and symbiont traits is a major issue in the ecology of symbiosis. A first step in this inquiry is to know whether observed differences among host species are species-specific traits or more related with host-symbiont environmental conditions. Here we analysed the repeatability (R) of the intensity and the prevalence of feather mites to partition within- and among-host species variance components. We compiled the largest dataset so far available: 119 Paleartic passerine bird species, 75,944 individual birds, ca. 1.8 million mites, seven countries, 23 study years. Several analyses and appro…
Weather impacts on interactions between nesting birds, nest-dwelling ectoparasites and ants.
2022
AbstractWeather has a dominant impact on organisms, including their life histories and interspecific interactions. Yet, for nesting birds, and the arthropods inhabiting bird nests, the direct and cascading effects of weather are poorly known. We explored the influence of ambient temperatures and rainfall on the cohabitation of dome-shaped bird nests by Wood Warblers Phylloscopus sibilatrix, their blowfly Protocalliphora azurea ectoparasites, and predatory Myrmica and Lasius ants that may provide nest sanitation. We sampled blowflies and ants in 129 nests, and measured warbler nestlings during 2018–2020 in the primeval Białowieża Forest, eastern Poland. The probability of ectoparasites occur…
Prevalence of tick-borne pathogens in ticks collected from migratory birds in Latvia.
2014
Migratory birds act as hosts and long-distance vectors for several tick-borne infectious agents. Here, feeding Ixodes ticks were collected from migratory birds during the autumn migration period in Latvia and screened for the presence of epidemiologically important non-viral pathogens. A total of 93 DNA samples of ticks (37 larvae and 56 nymphs) removed from 41 birds (order Passeriformes, 9 species) was tested for Lyme borreliosis spirochaetes, Anaplasma phagocytophilum, Rickettsia spp., and Babesia spp. Borrelia burgdorferi DNA was detected in 18% of the tick samples, and a majority of infected ticks were from thrush (Turdus spp.) birds. Among the infected ticks, Borrelia valaisiana was de…
Clutch size and egg volume in great tits (Parus major) increase under low intensity electromagnetic fields: a long-term field study.
2012
Exposure to electromagnetic fields (EMFs) can affect a wide range of biological processes, including reproduction, growth and development. Experiments aimed at investigating the biological effects of EMFs, focused on potential harmful effects on humans, have been mostly carried out in vitro or with animal models in laboratory conditions. By contrast, studies performed on wild animals are scarce. The effects of EMFs created by an electric power line on reproductive traits of a wild great tit (Parus major) population were explored by analysing data gathered during nine breeding seasons. EMF exposure significantly increased clutch size (7%) and egg volume (3%), implying a 10% increase in clutc…