Endocrine control of nestling begging behaviour in the pied flycatcher, Ficedula hypoleuca

Goodship, Nicola M. 2006. Endocrine control of nestling begging behaviour in the pied flycatcher, Ficedula hypoleuca. PhD Thesis, Cardiff University.

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Abstract

Begging signals given by nestling birds may advertise their condition or quality and parents may respond by allocating their resources in relation to begging intensity. In order for such signals to be honest, they must be costly to produce. The aim of this project was to investigate the role of nestling endogenous testosterone (T) as a potential mechanism to control begging signals in pied flycatchers, Ficedula hypoleuca. Androgen levels were analysed from invasive and non-invasive (faecal) samples using T radioimmunoassay. In the laboratory, nestling begging behaviour was measured as: 1) the duration of begging displays and 2) the maximum height of begging stretches. It was found that individual nestlings begging most intensively had the highest circulating levels of T immediately after testing. This relationship was tested experimentally by dosing nestlings with oral doses of T and assessing the effects on nestling begging signals. The results showed that the duration of begging displays by T-dosed nestlings were longer than controls, confirming the causal nature of T in controlling nestling begging signals. A field study investigated the effect of brood reduction on parental provisioning strategies, nestling behaviour and T levels. During brood reduction parents allocated food resources according to rules based more strongly on nestling begging behaviour compared with control days. A partial cross-fostering experiment tested whether nestling T and begging behaviour related to levels of relatedness within the nest. The begging duration of cross-fostered broods was longer than control broods and fostered nestlings increased their faecal androgen levels, although the reliability of this result should be further investigated. A biochemical validation study confirmed that excreted androgen metabolites were measured in the faeces of pied flycatchers. Overall, the results of this project confirmed that T is responsible in part for the control of begging intensity and may be a mechanism that controls begging behaviour in nestling birds.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Biosciences
Subjects:	Q Science > Q Science (General)
ISBN:	9781303206641
Funders:	Biotechnology and Biological Sciences Research Council (BBSRC)
Date of First Compliant Deposit:	30 March 2016
Last Modified:	19 Mar 2016 23:33
URI:	https://orca.cardiff.ac.uk/id/eprint/56109

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