11 research outputs found
AnĂĄlise da variabilidade da frequĂȘncia cardĂaca em cordeiros da raça BergamĂĄcia, do nascimento aos 35 dias de idade
Intrasexual competition and throat color evolution in female three-spined sticklebacks
Interest in the evolution of female ornaments has been growing but explaining their presence remains a challenge for many animal taxa. Although female ornaments may be sexually selected via male choice, they can also function in femaleâfemale competition. Here, we studied a stream-resident population of three-spined sticklebacks (Gasterosteus aculeatus), in which females possess male-typical red throat coloration, and a nearby anadromous population that lacks such coloration and is thought to possess ancestral character states for most traits in this species complex. We asked first whether there were population-level differences in agonism that might be associated with the evolution of female ornaments. We tested if the derived population possessing some red-throated females exhibited relatively higher levels and clearer patterns of within-population aggression and dominance in dyadic trials and more frequent behavioral dominance over individuals of the population lacking red females. Second, to address the relationship between the derived coloration and femaleâfemale competition, we tested whether red-throated stream females were more aggressive and dominant toward dull-throated stream females in both dyadic and socially complex contexts. We found that clear dominance was established more often in pairs of stream females, and stream females were more often dominant in stream-anadromous dyads. However, we found no clear evidence that the red throat coloration was directly linked to a female competitive advantage within the stream population, suggesting alternative untested signaling or perhaps nonadaptive functions. Our study represents the first evaluation of the potential relationship between a male-typical nuptial trait and intrasexual competition in female three-spined sticklebacks
Supplementary winter feeding of wild red deer Cervus elaphus in Europe and North America: justifications, feeding practice and effectiveness
Age-related change in breeding performance in early life is associated with an increase in competence in the migratory barn swallow Hirundo rustica
The occurrence of Pontoporia blainvillei (Gervais & d'Orbigny) (Cetacea, Pontoporiidae) in an estuarine area in southern Brazil OcorrĂȘncia de Pontoporia blainvillei (Gervais & d'Orbigny) (Cetacea, Pontoporiidae) em uma regiĂŁo estuarina no sul do Brasil
The toninha, or franciscana, Pontoporia blainvillei (Gervais & D'Orbigny, 1844), is an endemic species of cetacean of the southwestern Atlantic Ocean. There is little information on the occurrence of this species in its natural environment due to the great difficulty in sighting it. Systematized and non-systematized observations of franciscanas were made from December 1996 through November 2001 at Babitonga Bay, on the northern coast of Santa Catarina State, southern Brazil. The observations were made from small motorboats. A total of 79 observations were made, totaling 561 individuals. Up to 59.5% of the groups consisted of over four individuals and the average group size was seven. Calves were present in 30.4% of the observations. The species was found throughout the year within the bay and preferential areas were identified. Calves were registered during all seasons. Data are presented on the behavior (feeding, traveling, aerial behavior and behavior relating to the boats) and on inter-specific interactions with terns, cormorants [Phalacrocorax brasilianus (Gmelin, 1789)] and brown boobies [Sula leucogaster (Boddaert, 1783)]. The species is sympatric with the estuarine dolphin Sotalia guianensis (P. J. Van BĂ©nĂ©den, 1864) in the bay, but there was no record of interaction between them. The area of the bay represents an important refuge for the franciscana species.<br>A toninha, ou franciscana, Pontoporia blainvillei (Gervais & D'Orbigny, 1844), Ă© uma espĂ©cie endĂȘmica de cetĂĄceos que ocorre no Oceano AtlĂąntico sul ocidental. Existem poucas informaçÔes sobre a ocorrĂȘncia da espĂ©cie em seu ambiente natural em função da grande dificuldade em avistĂĄ-la. ObservaçÔes sistematizadas e nĂŁo-sistematizadas de franciscanas foram realizadas no perĂodo entre dezembro de 1996 e novembro de 2001 na BaĂa da Babitonga, no litoral norte do estado de Santa Catarina, sul do Brasil. As observaçÔes foram realizadas a partir de pequenas embarcaçÔes a motor. Um total de 79 observaçÔes foram efetuadas, totalizando 561 indivĂduos. Acima de 59.5% dos grupos eram compostos por mais de quatro indivĂduos e a mĂ©dia de tamanho de grupo foi de sete. Filhotes estiveram presentes em 30.4% das observaçÔes. A espĂ©cie foi encontrada na baĂa ao longo de todo o ano e foram identificadas ĂĄreas de uso preferencial. Filhotes foram registrados em todas as estaçÔes. SĂŁo apresentadas informaçÔes sobre o comportamento (alimentação, deslocamento, comportamentos aĂ©reos e relativos a embarcaçÔes) assim como sobre interaçÔes interespecĂficas com trinta-rĂ©is, biguĂĄs [Phalacrocorax brasilianus (Gmelin, 1789)] e atobĂĄs marrons [Sula leucogaster (Boddaert, 1783)]. A espĂ©cie Ă© simpĂĄtrica do golfinho estuarino Sotalia guianensis (P. J. Van BĂ©nĂ©den, 1864) na baĂa, mas nĂŁo foram efetuados registros de interação entre ambas as espĂ©cies. A ĂĄrea da baĂa representa um importante refĂșgio para a franciscana