1,721,148 research outputs found
Endocrinology in field studies: problems and solutions for the experimental design
No full textThe increasing interest in hormones among field biologists can be frustrating because of the difficulties of applying classical endocrinological methods to natural settings. A few thoroughly tested methods have become popular because of their simplicity of use. This does not mean that such methods are the best or the appropriate ones for all studies. In this brief review I will examine some common problems encountered by field biologists who want to study the relationships between a morphological, behavioral, or physiological trait and a hormone. First, I will discuss why questions asked in the field often differ substantially from those asked in the lab, and how to adapt the design of the experiment accordingly. Second, I will review alternative methods to study hormone-trait relationships and how to combine them to strengthen the conclusions that can be drawn from the study. Then, I will discuss how to find the right control for a hormonal manipulation. Finally, I will examine the pitfalls associated with long-term hormonal treatment and the available methods for such types of studies
HORMAN
No full text2009-2010. Consorzio Spinner 2013. Regione Emilia-Romagna. Finanziamento per lo sviluppo di idee d'impresa e trasferimento tecnologico dei prodotti della ricerca
Testosterone control of male courtship in birds
No full textA sequence of behaviours which we call courtship initiates reproduction in a large number of species. In vertebrates, as a component of male sexual behaviour courtship is strongly influenced by testicular androgen. Here I will review some salient issues about the regulation of courtship by testosterone in birds. The first section will briefly summarize the first 100 years of research on this topic. The specific role of testosterone or its oestrogenic metabolites in the control of different components of courtship will be the subject of the second section. Then, I will discuss how behavioural patterns can be recruited into courtship and modified in their structure by testosterone action. In the following section, the role of sexual selection and female choice in shaping the link between testosterone and courtship will be addressed. The problematic nature of the quantitative relationships between testosterone and behaviour will be topic of the fifth section. Finally, I will discuss how courtship traits that are activated by testosterone can be apparently independent of hormone blood concentrations. These issues will be examined in an evolutionary perspective, in an attempt to understand how natural and sexual selection have shaped the links between the hormone and the behaviour
Individual differences in the courtship displays of male Golden-collared Manakins: The bases for mate choice?
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Physiological control of nocturnal migration
No full textProgramma Vigoni
Collaborazione Italia-Germania 2011-2012
Nocturnally migratory birds interrupt migration temporarily if they have depleted energy reserves and find suitable ‘refuelling’ sites. Besides weather conditions, a major determinant of whether a bird rests or continues migration is body fat. We are interested in understanding which physiological mechanisms switch on and off nocturnal migration during and after refuelling at a stop-over site. We have identified a candidate hormone, ghrelin, that may be a major player in influencing decisions to migrate or not. The aim of this project is to substantiate (or disprove) the evidence for the role of ghrelin in the regulation of migratory behavior
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