Incubation temperature influences locomotor performance in young wood ducks (Aix sponsa)

Abstract

Incubation temperature is an important maternal effect in birds that can influence numerous offspring traits. For example, ducklings from eggs incubated at lower temperatures have lower growth rates, protein content, and are in poorer body condition than ducklings from eggs incubated at higher temperatures. Based on these observations, we predicted that incubation temperature would indirectly influence performance through its direct effects on body size. Wood duck (Aix sponsa) eggs were incubated at three ecologically relevant temperatures (35, 35.9, 37°C). After hatching, all ducklings were housed under identical conditions and were subjected to aquatic and terrestrial racing trials at 15 and 20 days posthatch (dph). Contrary to our prediction, incubation temperature did not influence most duckling body size parameters at 15 or 20 dph. However, incubation temperature did have a strong influence on locomotor performance independent of body size and body condition. Ducklings hatched from eggs incubated at the lowest temperature had significantly reduced maximum aquatic swim velocity than ducklings from higher temperatures. Maximum terrestrial sprint velocity followed a similar pattern, but did not differ statistically among incubation treatments. To our knowledge, this is the first study to demonstrate that slight changes in incubation temperature can directly affect locomotor performance in avian offspring and thus provide a significant source of phenotypic variation in natural wood duck populations.

Embryonic Developmental Patterns and Energy Expenditure Are Affected by Incubation Temperature in Wood Ducks (Aix sponsa)

“…Our previous studies, using the same incubation temperature treatments as this study, have found that ducklings incubated at the lowest temperature have reduced physiological performance relative to ducklings incubated at the higher temperatures (Hepp et al 2006;DuRant et al 2010DuRant et al , 2011Hopkins et al 2011;S. E. DuRant, W. A. Hopkins, A. F. Wilson, and G. R. Hepp, unpublished manuscript).…”

“…Several other studies on wood ducks have revealed that incubation temperature affects duckling phenotype after hatching as well. These studies have found that ducklings from the low incubation temperature group have slower growth, reduced thermoregulatory performance, reduced immune responses, higher corticosterone concentrations, and reduced locomotor performance (DuRant et al 2010Hopkins et al 2011;S. E. DuRant, W. A. Hopkins, A. F. Wilson, and G. R. Hepp, unpublished manuscript).…”

“…However, recent research has demonstrated that subtle changes in incubation temperature can greatly influence avian hatchling characteristics (Goth and Booth 2005;Hepp et al 2006;Olson et al 2008;DuRant et al 2010DuRant et al , 2011Hopkins et al 2011;S. E. DuRant, W. A. Hopkins, A. F. Wilson, and G. R. Hepp, unpublished manuscript).…”

Incubation temperature affects multiple measures of immunocompetence in young wood ducks (Aix Sponsa)

“…However, studies have only recently revealed the consequences of variation in incubation temperature for avian phenotype. In wood ducks (Aix sponsa), slight differences (less than 18C) in incubation temperature, reflecting variation of average temperatures of naturally incubated wood duck nests [6], influence duckling body composition, growth, condition, locomotor performance and stress hormone concentrations [6][7][8]. These results, along with several studies that detected correlations between avian immune parameters and incubation period among species [9,10], suggest that incubation temperature also might influence duckling immune responses.…”

“…Specifically, ducklings from the low incubation temperature had 19 -21% lower swelling in response to PHA injection and 32 -38% lower SRBC responses than ducklings from the two higher incubation temperatures. Precocial species like the wood duck begin interacting with their environment shortly after hatching [7,8], so that compromised immunocompetence may make them more susceptible to pathogens and parasites they encounter while foraging.…”