323,035 research outputs found
Social cohesion and foraging decrease with group size in fallow deer (Dama dama)
No full textWe studied the impact of group size on foraging behaviour and level of movement synchronisation among female herdmates of a fallow deer population in Central Italy. Both proportion of foraging events and movement synchronisation decreased with increasing group size. The proportion of foraging events was higher for animals on the
edge of the group than for deer in the centre of the group; hence, there appears to be a trade-off between protection against predators and foraging interference, both of which decrease from the centre to the periphery of the group. This is the first time this type of behaviour has been recorded for wild ungulates. As expected, we also found that the movement of peripheral animals was less synchronised than that
of central animals. Consequently, peripheral animals may lose contact with their herdmates and split off the group. We conclude that social inequalities may lead to conflicting requirements among group members and instability of large groups. Movement synchronisation (as a function
of group size) appears to interact with habitat openness to produce variations of group size (which appear to be adaptive for individuals) as an emergent property of these
aggregations
Genetic structure of the toxic marine protist Alexandrium minutum (dinoflagellate) in the Mediterranean Sea: implications for the control and management of the HAB events.
No full textAdaptive Lévy walks in foraging fallow deer.
No full textBACKGROUND: Lévy flights are random walks, the step lengths of which come from probability distributions with heavy power-law tails, such that clusters of short steps are connected by rare long steps. Lévy walks maximise search efficiency of mobile foragers. Recently, several studies raised some concerns about the reliability of the statistical analysis used in previous analyses. Further, it is unclear whether Lévy walks represent adaptive strategies or emergent properties determined by the interaction between foragers and resource distribution. Thus two fundamental questions still need to be addressed: the presence of Lévy walks in the wild and whether or not they represent a form of adaptive behaviour. METHODOLOGY/PRINCIPAL FINDINGS: We studied 235 paths of solitary and clustered (i.e. foraging in group) fallow deer (Dama dama), exploiting the same pasture. We used maximum likelihood estimation for discriminating between a power-tailed distribution and the exponential alternative and rank/frequency plots to discriminate between Lévy walks and composite Brownian walks. We showed that solitary deer perform Lévy searches, while clustered animals did not adopt that strategy. CONCLUSION/SIGNIFICANCE: Our demonstration of the presence of Lévy walks is, at our knowledge, the first available which adopts up-to-date statistical methodologies in a terrestrial mammal. Comparing solitary and clustered deer, we concluded that the Lévy walks of solitary deer represent an adaptation maximising encounter rates with forage resources and not an epiphenomenon induced by a peculiar food distribution
Applicazione di marcatori molecolari polimorfici per studi di genetica di popolazione su Alexandrium minutum nel Mar Mediterraneo
No full textRicerche italiane in Anatolia : risultati delle attività sul campo per le età del bronzo e del ferro
No full textVolume dedicato alle ricerche italiane in Turchia con i risultati recenti di progetti di scavo e studio, dall'età del Bronzo all'età del Ferro, tra l'altopiano centro-anatolico, l'Eufrate e l'alto corso del Tigr
Ebla et ses souvérains.Du renouvellement de la Ville protosyrienne tardive à l'épanouissement du regne amorrehen
No full textRicognizione archeologica a Yassihuyuk (2004-2009)
No full textresoconto sintetico dell'attività di ricognizione condotta sul sito di Yassihuyuk, in Anatolia centrale, con descrizione dei ritrovamenti principal
Population genetic structure of the toxic Dinophyceae Alexandrium minutum in the Mediterranean Sea: a case study
No full textPresentazione oral
Note sulle transazioni della famiglia di Anu-uballit f. Anu-ahhe-iddin d. Sin-leqe-unneni
No full text- …
