Incubation Temperature Affects Duckling Body Size and Food Consumption Despite No Effect on Associated Feeding Behaviors

Journal Article · 04 February 2020 · Integrative Organismal Biology

DOI: https://doi.org/10.1093/iob/obaa003 · OSTI ID:1617963

Hope, S. F.  ^[1]; Kennamer, R. A. ^[2]; Grimaudo, A. T. ^[1]; Hallagan, J. J. ^[1]; Hopkins, W. A. ^[1]

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1. Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA, USA
2. Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA

Synopsis Developmental conditions can have consequences for offspring fitness. For example, small changes (<1°C) in average avian incubation temperature have large effects on important post-hatch offspring phenotypes, including growth rate, thermoregulation, and behavior. Furthermore, average incubation temperatures differ among eggs within the same nest, to the extent (i.e., >1°C) that differences in offspring phenotypes within broods should result. A potential consequence of within-nest incubation temperature variation is inequality in behaviors that could cause differences in resource acquisition within broods. To investigate this, we incubated wood duck (Aix sponsa) eggs at one of two ecologically-relevant incubation temperatures (35°C or 36°C), formed mixed-incubation temperature broods after ducklings hatched, and conducted trials to measure duckling behaviors associated with acquisition of heat (one trial) or food (three trials). Contrary to our predictions, we found no effect of incubation temperature on duckling behaviors (e.g., time spent occupying heat source, frequency of feeding bouts). However, we found evidence that ducklings incubated at the higher temperature consumed more food during the 1-h feeding trials, and grew faster in body mass and structural size (culmen and tarsus) throughout the study, than those incubated at the lower temperature. Apparent food consumption during the trials was positively related to culmen length, suggesting that differences in food consumption may be driven by structural size. This could result in positive feedback, which would amplify size differences between offspring incubated at different temperatures. Thus, our study identifies incubation temperature as a mechanism by which fitness-related phenotypic differences can be generated and even amplified within avian broods.

• Research Organization: Univ. of Georgia, Athens, GA (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE
• Grant/Contract Number: FC09-07SR22506
• OSTI ID: 1617963
• Journal Information: Integrative Organismal Biology, Journal Name: Integrative Organismal Biology Journal Issue: 1 Vol. 2; ISSN 2517-4843
• Publisher: Oxford University PressCopyright Statement
• Country of Publication: United Kingdom
• Language: English