A carregar...
Publicação
Estratégias energéticas e comportamentais de adaptação à temperatura no musaranho-comum (Crossidura russula)
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 4.79 MB | Adobe PDF |
Orientador(es)
Resumo(s)
A temperatura ambiente é um dos fatores ecológicos mais importantes na sobrevivência dos micromamíferos. O balanço entre a aquisição e o gasto de energia depende da quantidade de energia investida em diferentes funções, como a termorregulação, o crescimento, a reprodução e o comportamento. Neste estudo investigámos a capacidade termogénica e os padrões de atividade e comportamento em Crocidura russula de forma a avaliar a influência destes fatores na adaptação a diferentes temperaturas ambientais. Para tal, capturou-se vários indivíduos na Serra de Sintra que foram divididos em três grupos: um grupo controlo, sujeito durante duas semanas a um período de luz diários de 12 horas e uma temperatura ambiente de 20 °C; um grupo capturado e aclimatizado às condições de inverno; e um grupo capturado e aclimatizado às condições de verão. A comparação destes três grupos experimentais revelou que a taxa metabólica dos animais, apesar de não ter variado, foi superior ao que seria de esperar comparativamente a outros estudos, e a termogénese sem tremor apenas sofreu um ligeiro aumento no inverno. Os animais estiveram mais ativos no verão, mas esta diferença não foi evidente por estar relacionada com as alterações sazonais ambientais que ocorrem, como o fotoperíodo ou a temperatura. Nem a preferência alimentar nem a quantidade de alimento consumido variou entre os grupos, mas os animais passaram mais tempo a alimentar-se quando estavam em atividade no inverno. Os animais também apresentaram diferenças no torpor diário, tendo-se constatado o papel relevante do torpor na conservação de energia. Os resultados revelaram que o C. russula possui uma estratégia de conservação energética bastante diferente dos musaranhos da subfamília Soricinae, mais bem estudados atualmente.
Ambient temperature is one of the most important ecological factors in the survival of small mammals. The balance between acquisition and expenditure of energy depends on the amount of energy allocated to different functions such as thermoregulation, growth, reproduction and behavior. In this study, the role of thermogenic capacity and activity and behavior patterns in the adaptation to different ambient temperatures was investigated in the common shrew, Crocidura russula. Several individuals were therefore captured in Serra de Sintra and split into three groups: a control group, acclimated to a 12-12h photoperiod and a constant temperature of 20 ºC; a winter group, acclimatized to winter conditions; and a summer group, acclimatized to summer conditions. Comparison between these three groups revealed that the metabolic rate, despite not having changed, was greater than expected from other studies, and nonshivering thermogenesis suffered only a slightly increase in winter. Shrews showed more activity in summer, although this wasn’t evident because it was masked by seasonal environmental changes, like photoperiod or temperature. Food preference and amount of consumed food didn’t show a marked difference between groups, but the shrews acclimatized to winter spent more time eating when in activity. Shrews also presented differences in daily torpor, showing its role in energy conservation. The results revealed that C. russula uses a very different strategy of energy conservation from the more well studied soricine shrews.
Ambient temperature is one of the most important ecological factors in the survival of small mammals. The balance between acquisition and expenditure of energy depends on the amount of energy allocated to different functions such as thermoregulation, growth, reproduction and behavior. In this study, the role of thermogenic capacity and activity and behavior patterns in the adaptation to different ambient temperatures was investigated in the common shrew, Crocidura russula. Several individuals were therefore captured in Serra de Sintra and split into three groups: a control group, acclimated to a 12-12h photoperiod and a constant temperature of 20 ºC; a winter group, acclimatized to winter conditions; and a summer group, acclimatized to summer conditions. Comparison between these three groups revealed that the metabolic rate, despite not having changed, was greater than expected from other studies, and nonshivering thermogenesis suffered only a slightly increase in winter. Shrews showed more activity in summer, although this wasn’t evident because it was masked by seasonal environmental changes, like photoperiod or temperature. Food preference and amount of consumed food didn’t show a marked difference between groups, but the shrews acclimatized to winter spent more time eating when in activity. Shrews also presented differences in daily torpor, showing its role in energy conservation. The results revealed that C. russula uses a very different strategy of energy conservation from the more well studied soricine shrews.
Descrição
Tese de mestrado. Biologia (Biologia da Conservação). Universidade de Lisboa, Faculdade de Ciências, 2013
Palavras-chave
Micromamíferos Temperatura ambiente Conservação energética Serra de Sintra - Portugal Teses de mestrado - 2013