SREL Reprint #3700

Warmer incubation temperatures and later lay-orders lead to shorter telomere lengths in wood duck (Aix sponsa) ducklings

Sydney F. Hope1,2, Frédéric Angelier2, Cécile Ribout2, Jordy Groffen1, Robert A. Kennamer3,
and William A. Hopkins1

1Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, USA
2Centre d'Etudes Biologiques de Chizé, CNRS-La Rochelle Université, UMR 7372,
Villiers en Bois, France
3Savannah River Ecology Lab, University of Georgia, Aiken, South Carolina, USA

Abstract: The environment that animals experience during development shapes phenotypic expression. In birds, two important aspects of the early-developmental environment are lay-order sequence and incubation. Later-laid eggs tend to produce weaker offspring, sometimes with compensatory mechanisms to accelerate their growth rate to catch-up to their siblings. Further, small decreases in incubation temperature slow down embryonic growth rates and lead to wide-ranging negative effects on many posthatch traits. Recently, telomeres, noncoding DNA sequences at the end of chromosomes, have been recognized as a potential proxy for fitness because longer telomeres are positively related to lifespan and individual quality in many animals, including birds. Although telomeres appear to be mechanistically linked to growth rate, little is known about how incubation temperature and lay-order may influence telomere length. We incubated wood duck (Aix sponsa) eggs at two ecologically-relevant temperatures (34.9°C and 36.2°C) and measured telomere length at hatch and 1 week after. We found that ducklings incubated at the lower temperature had longer telomeres than those incubated at the higher temperature both at hatch and 1 week later. Further, we found that later-laid eggs produced ducklings with shorter telomeres than those laid early in the lay-sequence, although lay-order was not related to embryonic developmental rate. This study contributes to our broader understanding of how parental effects can affect telomere length early in life. More work is needed to determine if these effects on telomere length persist until adulthood, and if they are associated with effects on fitness in this precocial species.

Keywords: early developmental environment, incubation temperature, lay-order sequence, parental effect, precocial bird, telomere

SREL Reprint #3700

Hope, S., F. Angelier, C. Ribout, J. Groffen, R. Kennamer, and W. Hopkins. 2023. Warmer incubation temperatures and later lay-orders lead to shorter telomere lengths in wood duck (Aix sponsa) ducklings. Journal of Experimental Zoology Part A: Ecological and Integrative Physiology 339(1): 101-111.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).