Data Entry: Please note that the research database will be replaced by UNIverse by the end of October 2023. Please enter your data into the system https://universe-intern.unibas.ch. Thanks
Begging signals and biparental care : nestling choice between parental feeding locations
Journal
Animal Behaviour
Volume
55
Number
1
Pages / Article-Number
215-22
Keywords
begging; hunger; signalling; sexual conflict; female role; sex allocation; biparental care; POC; sibling competition; positioning; Parus major; extra-pair paternity
Abstract
The evolutionary conflict over the amount of resources transferred between a parent and its offspring may be resolved by honest signalling of 'need' by offspring and parental investment in relation to signalling level. In birds, biparental care is the norm and evidence that male and female parents differ in their investment pattern in individual offspring is growing. In an experiment on great tits, Parus major, we investigated how and why parents differ in food allocation when responding to similar chick signals, which supposedly uniquely reflect the chick's nutritional condition. Nestling hunger level was manipulated by food deprivation and hand-feeding. Subsequent filming revealed that parents fed from significantly different locations on the nest and thereby forced chicks to choose between them when competing for favourable positions. Deprived nestlings approached, and fed ones retreated (or were displaced by siblings) from, positions near the female. No such behaviour was observed towards the male. Females allocated more feeds than males to the food-deprived nestlings. The results are discussed in terms of nestling competition for access to 'begging patches'. By varying their 'begging patch' value, parents may exploit competitive inter-sibling dynamics to influence the outcome of competition among chick phenotypes (e.g. 'need', size, sex). Parent birds may thereby exert considerable control over the information content of chick begging behaviour. (C) 1998 The Association for the Study of Animal Behaviour.
