Document Type
Article
Publication Title
The American Naturalist
Publication Date
5-2019
Keywords
corticosterone, glucocorticoid, house wren, life history, parental care, parent-offspring conflict
Abstract
The coevolution of parental supply and offspring demand has long been thought to involve offspring need driving begging and parental care, leaving other hypotheses underexplored. In a population of wild birds, we experimentally tested whether begging serves as a negatively condition-dependent signal of need or a positively condition-dependent signal of quality. Across multiple years, we supplemented nestling house wrens with food shortly after hatching and simultaneously manipulated corticosterone levels to simulate the hunger-induced increase in glucocorticoids thought to mediate begging. This allowed us to also test whether begging is simply a proximate signal of hunger. Days after supplementation ended, food-supplemented nestlings were in better condition than nonsupplemented nestlings and begged for food at an increased rate; their parents, in turn, increased provisioning to a greater extent than parents of nonsupplemented young, as begging positively predicted provisioning. Food-supplemented nestlings therefore attained above-average condition, which predicted their recruitment as breeding adults in the local population. Glucocorticoids increased begging in the short term, but this transient effect depended on satiety. Thus, glucocorticoids promoted begging as a proximate response to hunger, whereas the longer-term changes in nestling condition, begging, and food provisioning suggest that begging ultimately signals offspring quality to elicit increased investment, thereby enhancing offspring survival.
Funding Source
Financial support was provided by National Science Foundation grants IBN-0316580, IOS-0718140, and IOS-1118160; National Institutes of Health grant R15HD076308; the Department of Biological Sciences at the University of Memphis and School of Biological Sciences at Illinois State University; and a post-doctoral research grant from the American Ornithological Society.
Recommended Citation
Bowers, E.K., Jenkins, J.B., Mueller, A.J., Miller, K.D., Thompson, C.F. and S.K. Sakaluk. 2019. Condition-dependent begging elicits increased parental investment in a wild bird population. American Naturalist 193: 725-737. https://doi.org/10.1086/702848
DOI
10.1086/702848
Comments
This is the accepted manuscript of an article first published in Physiological and Biochemical Zoology (2019): https://doi.org/10.1086/702848
Copyright held by The University of Chicago.