Effect of humidity on basal metabolic rate, thermal conductance and the breadth of the thermoneutral zone in two species of Stilpnia tanagers (Family Thraupidae)
Although the effects of different ecological factors on avian metabolism have been studied, it is not clear how humidity affects the relationship between metabolic rate and ambient temperature. An increase in relative humidity arguably makes it more difficult for animals to dissipate heat. In respon...
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| 格式: | bachelorThesis |
| 语言: | eng |
| 出版: |
2025
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| 主题: | |
| 在线阅读: | http://repositorio.yachaytech.edu.ec/handle/123456789/888 |
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添加标签 | 总结: | Although the effects of different ecological factors on avian metabolism have been studied, it is not clear how humidity affects the relationship between metabolic rate and ambient temperature. An increase in relative humidity arguably makes it more difficult for animals to dissipate heat. In response, species might evolve to adjust their 1) basal metabolic rate (BMR), 2) thermal conductance (C), and/or 3) breadth of the thermoneutral zone (TNZ). For this reason, the present study focused on comparing those three metabolic responses in two related tanager species, Stilpnia heinei and Stilpnia vitriolina (Family Thraupidae – Passeriformes), that inhabit humid cloud forests and dry forests, respectively. Metabolic rates were obtained with an open flow-through respirometry system. In addition, I analyzed published data to test for a correlation between humidity and BMR. in tropical birds. Data showed that S. heinei presented a greater BMR and a lower thermal conductance than S. vitriolina. Further, S. heinei apparently showed a broader TNZ than S. vitriolina. This probably indicated that S. heinei tends to tolerate a wider range of ambient temperatures, both low and high — a thermoregulatory mechanism known to be present in several tropical species. Although to interpret published results on metabolic rates can become a scientific conundrum, given the many variables acting on a bird metabolism, the analysis of over 478 species of passerines suggested that species in dry tropical areas have a lower BMR possibly due to scarcity of resources, such as water and food. These results could represent a starting point towards the study of ecophysiological responses of tropical birds to different challenges imposed by their environment. |
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