191 research outputs found

    Coping with style: individual differences in responses to environmental variation

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    Anti-predator behaviour of the red-legged partridge Alectoris rufa (Galliformes: Phasianidae) to simulated terrestrial and aerial predators

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    This study is intended to investigate the differences in anti-predator behavioural and acoustic response to terrestrial and aerial predators as well as the behavioural differences between sexes in the red-legged partridge. To this aim we observed the response of 114 partridge (57 males and 57 females) to dummy terrestrial and aerial predators, a raptor and a fox. We divided behavioural responses to predators into four mutually exclusive categories: vigilance, freezing, escape and non-anti-predator behaviours. We also recorded and analysed the vocalizations emitted during tests. The animals reacted differently to aerial and terrestrial stimuli. The reactions elicited by the terrestrial predator were ranked as follows: vigilance, escape, non-anti-predator behaviours, and freezing. Those elicited by the aerial predator were ranked as follows: vigilance, freezing, escape and non-anti-predator behaviours. Vigilance and escape were elicited more frequently by the terrestrial predator than by the aerial predator (vigilance: p 0.001; escape: p 0.001). Freezing was the most frequent behaviour following the appearance of the aerial predator (p 0.001). In fact, freezing may represent an effective strategy in an open space, combining camouflage from and detection by the predator. On the other hand, vigilance is an effective behaviour to detect and avoid a terrestrial predator hunting by ambush. We did not find clear-cut differences between sexes. The analysis of vocalizations revealed that the fox and the raptor elicited significantly different calls (p = 0.003); the fox evoked significantly more vocalizations than the raptor (p 0.001), differing in addition in frequency parameters. Thus partridges not only discriminate between aerial and terrestrial predators and behave consequently, but are also able to tune alarm calls in relation to the context of predation

    Heavy metals in the muscle and hepatopancreas of red swamp crayfish (Procambarus clarkii) in campania (italy)

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    The aim of this study was to carry out a quali-quantitative analysis of the presence of non-essential and essential trace elements in freshwater crayfish (Procambarus clarkii) edible tissues to establish the healthiness of this product and to evaluate the pollution status of the sampling sites included in the present study. P. clarkii is one of the most common species of freshwater crustaceans in Italy, regularly consumed by local people. Moreover, the crayfish, due to its trophic position and diet, can be considered as an excellent bioindicator of the health status of the ecosystem. We collected sixty crayfish samples from two different sites in Campania (Italy): Villa Literno and Sessa Aurunca. Concentrations of trace elements were determined by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Our data showed low concentrations of Cd, Hg and Pb, with values below the European Commission MRL (Commission Regulation (EC) 1881/2006). We suggest that data obtained from this study showed that crayfish collected from Villa Literno and Sessa Aurunca were safe for human consumption. Furthermore, the results of this research indicated mild contamination of heavy metals of the sampling sites, indicating a good health status of the area’s aquatic ecosystem

    Functional feeding groups of aquatic insects influence trace element accumulation: Findings for filterers, scrapers and predators from the po basin

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    For this study, we measured the concentrations of 23 trace elements (Al, As, Ba, Bi, Cd, Cr, Co, Cu, Fe, Ga, Hg, In, Li, Mn, Mo, Ni, Pb, Se, Sr, Ti, Tl, V, and Zn) in the whole bodies of three functional feeding groups (FFG) (filterers—Hydropsychidae, scrapers—Heptageniidae, and predators—Odonata) of aquatic insects collected from two sites in the Po basin (Po Settimo and Malone Front, Northwest Italy) to determine: (a) how FFG influence trace element accumulations, (b) if scrapers accumulate higher elements compared to the other FFG, since they graze on periphyton, which represents one of the major sinks of metals, and (c) the potential use of macroinvertebrates to assess the bioavailability of trace elements in freshwater. The hierarchical clustering analysis generated three main groups based on trace element concentrations: the most abundant elements were Fe and Al, followed by Sr, In, Zn, V, Mo, and Cu. Tl was below the limit of detection (LOD) in all FFG. Ga was detected only in scrapers from both sites and Hg only in predators from Po Settimo. The principal component analysis showed that concentrations of Al, As, Bi, Cd, Co, Cr, Ga, Fe, In, Mn, Pb, Ni, and Sr were highest in scrapers, suggesting that trace elements accumulate from the ingestion of epilithic periphyton (biofilm). Odonata (predators) accumulate certain elements (Ba, Hg, Li, Se, V, Ti, and Zn) in higher concentrations by food ingestion composed of different aquatic organisms. Differently, Cu and Mo concentrations were the highest in filterers due to their bioavailability in the water column. Non-metric multidimensional scaling clearly differentiated the FFG based on their ability to accumulate trace elements. The findings from this study represent an important step toward the definition of an innovative approach based on trace element accumulation by macroinvertebrates

    Distinguishing personal belief from scientific knowledge for the betterment of killer whale welfare \u2013 a commentary

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    We contest publication of Marino et al. regarding captive killer whale (Orcinus orca) welfare because of misrepresentations of available data and the use of citations that do not support assertions. Marino et al. misrepresent stress response concepts and erroneously cite studies, which appear to support Marino et al.\u2019s philosophical beliefs regarding the cetacean hypothalamic\u2013pituitary\u2013adrenal axis. To be clear, these misrepresentations are not differences of scientific opinion, as the authors\u2019 conclusions lack any scientific basis. More extensive review of Marino et al.\u2019s citations reveal a dearth of empirical evidence to support their assertions. Further, Marino et al.\u2019s approach to animal welfare is not consistent with conventional veterinary approaches to animal welfare, including their apparent opposition to use of preventative and therapeutic veterinary interventions. While Marino et al. argue that killer whales\u2019 cognitive and spatial needs preclude management of this species under human care, misrepresentation of the citations used to support this opinion invalidates their arguments. Misleading interpretations of data relative to killer whales\u2019 cognitive and emotional needs and specious and unsubstantiated comparisons with states experienced by humans with posttraumatic stress disorder and other conditions, represent a number of strategies used to misrepresent knowledge regarding killer whale welfare. These misrepresentations and fallacies are inconsistent with scientific ethical standards for credible, peer-reviewed journals (ICMJE, 2018), and are barriers to rigorous discourse and identification of strategies for optimizing killer whale welfare. Assertions in the paper amount to nothing more than a compilation of conclusory, philosophical statements. We would also like to mention that manuscripts such as Marino et al.\u2019s do great damage to the fields of comparative psychology and to behavioral science as a whole

    Guest or pest? Spatio-temporal occurrence and effects on soil and vegetation of the wild boar on the Elba island

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    In areas where allochthonous large mammals, such as the wild boars (Sus scrofa), occur in high density, human-wildlife conflicts may arise. In these contexts, assessing spatio-temporal patterns of the introduced population is paramount to its management. Here, we studied wild boars in the Elba island, Italy, where they have been introduced and are perceived as pests. While crop-raiding has been documented, no studies addressed the spatio-temporal occurrence, nor the impact of foraging on natural habitat. We surveyed the Western part of the island with three camera trapping surveys within one year. We found that the species' estimated occupancy probability was higher in summer-autumn (0.75±0.14) and winter-early spring (0.70±0.10) than in late spring-summer (0.53±0.15), whereas detection probability did not vary. Occupancy was significantly associated with elevation and vegetation cover, with preference for lower elevation and woodland. The lower site use of wild boars during spring-summer might reflect lower food availability in this season, and/or movements towards landfarms outside the sampled area. Detectability increased with proximity to roads during spring-summer and decreased with humans' relative abundance in the other periods. Moreover, boars were mainly nocturnal, with an overlap with human activity that decreased when human presence was higher. Combined, these suggest behavioural avoidance of human disturbance by boars. We also evaluated the impact of boars' foraging on the soil and vegetation and found that it was higher in pine plantations than other covers, however, it was not associated with variation in boars' occupancy across habitats. Our results indicate that the spatio-temporal activity of wild boars on Elba island appears driven by seasonal preferences for food-rich cover and avoidance of human disturbance. The lowered site use in months with lower resources could partially reflect increased proximity to settled and farmed areas, which may, in turn, trigger crop-raiding and hence the negative perception by residents
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