Physiological stress in the Eurasian badger (Meles meles): Effects of host, disease and environment

A method for monitoring hypothalamic–pituitary–adrenal (HPA) responses of the Eurasian badger (Meles meles) to stressors was validated by measuring cortisol excretion in serum and faeces. Serum and faecal samples were collected under anaesthesia from live-captured, wild badgers and fresh faeces was collected from latrines at 15 social groups in County Down, Northern Ireland. Variation in levels of cortisol in wild badgers was investigated relative to disease status, season, age, sex, body mass, body condition and reproductive status and environmental factors that might influence stress. Faecal cortisol levels were significantly higher in animals testing culture-positive for Mycobacterium bovis. Prolonged elevation of cortisol can suppress immune function, which may have implications for disease transmission. There was a strong seasonal pattern in both serum cortisol, peaking in spring and faecal cortisol, peaking in summer. Cortisol levels were also higher in adults with poor body condition and low body mass. Faecal samples collected from latrines in grassland groups had significantly higher cortisol than those collected from woodland groups, possibly as a result of greater exposure to sources of environmental stress. This study is the first to investigate factors influencing physiological stress in badgers and indicates that serological and faecal excretion are valid indices of the HPA response to a range of stressors

Comportamento adjunto: controvérsias e contribuições teóricas

A área de investigação sobre comportamento adjunto, cujas pesquisas tiveram início na década de 60, é extensa e controvertida. O presente trabalho analisa as interpretações mais importantes do fenômeno, e mostra que diversas características apresentadas como próprias do comportamento adjunto também estão presentes em outros comportamentos. Falk interpretou o comportamento adjunto como atividade deslocada, Staddon como comportamento induzido por esquema, Timberlake como parte de um sistema comportamental pré-programado, e Wetherington questionou a existência de uma terceira classe de comportamento. Conclui-se que as tentativas de sistematização têm se mostrado incompletas devido à diversidade de topografias de comportamentos adjuntos e a sua dependência de variáveis tanto do esquema como da espécie e do ambiente