Sex differences in food intake and digestive constraints in a nectarivorous bird.
نویسندگان
چکیده
Sex-specific foraging behaviour might be influenced by digestive constraints. However, evidence for sex differences in digestive performance is limited. Various physiological traits are known to be body size dependent. Therefore, we hypothesized that body size differences between male and female birds may lead to differences in their digestive characteristics. We predicted that if food intake and digestive functions are only governed by body mass, then males that are heavier than females would have higher food intake, food assimilation efficiency and gut transit time, but not after controlling for the effect of body mass. We fed a diet of equicaloric solutions of sucrose and a 1:1 mixture of glucose and fructose (hexose mixture) solutions to Palestine sunbirds (Nectarinia osea). When fed sucrose solutions, males had longer transit times but similar absorption efficiencies as females. Transit times, corrected for differences in body mass and food intake, were still longer in males than in females when fed on sucrose solutions. The sex-specific differences in transit time disappeared when the birds were fed the hexose mixture. Our results suggest that males take longer to digest than females when fed on sucrose-rich nectars as opposed to hexose-rich nectars, and therefore can allow themselves a relatively lower digestive capacity. This may suggest sex-specific co-evolution of sunbirds within mixed plant communities, which have both sucrose- and hexose-rich nectar-producing plants. Furthermore, future studies on digestion in birds may pay attention to sex-specific differences.
منابع مشابه
Spare capacity and phenotypic flexibility in the digestive system of a migratory bird: defining the limits of animal design.
Flexible phenotypes enable animals to live in environments that change over space and time, and knowing the limits to and the required time scale for this flexibility provides insights into constraints on energy and nutrient intake, diet diversity and niche width. We quantified the level of immediate and ultimate spare capacity, and thus the extent of phenotypic flexibility, in the digestive sy...
متن کاملEffects of nicotine on the digestive performance of nectar-feeding birds reflect their relative tolerance to this alkaloid.
The paradox of secondary metabolites, toxic defence compounds produced by plants, in nectar and fruits is well known. Deterrence of feeding by nectarivorous and frugivorous birds is better understood than the effect of these chemicals on the digestive performance of birds. Digestive parameters such as transit time and sugar assimilation are important in assessing nutrient utilization and deterr...
متن کاملCentral effect of mammalian oxyntomodulin on food intake in non-fasted and fasted chicks
Oxyntomodulin (OXM), a proglucagon-derived peptide, is a well known anorexigenic peptide found inthe gut and brain of mammals. The present study was carried out to investigate the central effect of OXM onfood intake in non-fasted and fasted Ross broiler chicks. At four weeks of age, a guide cannula wasstereotaxically implanted into the right lateral ventricle of each bird. Two experiments were ...
متن کاملRevista Brasileira de Zootecnia
The objective of this paper is to present some of the issues faced by those whose interest is to predict responses in poultry, concentrating mainly on those related to the prediction of voluntary food intake, as this should be the basis of models designed to optimise both performance and feeding programmes. The value of models designed to predict growth or reproductive performance has been impr...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The Journal of experimental biology
دوره 209 Pt 6 شماره
صفحات -
تاریخ انتشار 2006