Isotopic Evidence for Sources of Nutrients Allocated to Clutch Formation by Harlequin Ducks

Bond, Jeanine C.; Esler, Daniel; Hobson, Keith A.

doi:10.1093/condor/109.3.698

Cited by 18 publications

(12 citation statements)

References 33 publications

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“…representing exogenous allocations, Hobson 1995) but not for endogenous reserves to egg. To estimate discrimination values for endogenous reserves to egg formation, previous researchers (Gauthier et al 2003, Schmutz et al 2006, Bond et al 2007, Hobson et al 2011) have assumed that the mobilization of proteins to eggs from endogenous reserves involves similar isotopic discrimination as found for the carnivore model in Hobson (1995). Based on Hobson (1995), discrimination between diet and endogenous reserves to yolk protein formation was assumed to be 3.4‰ for δ 15 N. Discrimination value for δ 13 C in albumen production from lipid‐free invertebrates and lipid‐free endogenous reserves was assumed to be 0.9‰; whereas discrimination between albumen and wetland seed was assumed to be 1.5‰ (Hobson 1995).…”

Section: Methodsmentioning

confidence: 99%

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Endogenous contributions to egg protein formation in lesser scaup Aythya affinis

Cutting¹,

Hobson²,

Rotella³

et al. 2011

Journal of Avian Biology

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Lesser scaup Aythya affinis populations have declined throughout the North American continent for the last three decades. It has been hypothesized that the loss and degradation of staging habitats has resulted in reduced female body condition on the breeding grounds and a concomitant decline in productivity. We explored the importance of body (endogenous) reserves obtained prior to arrival on the breeding ground in egg protein formation in southwestern Montana during 2006–2008 using stable‐carbon (δ13C) and nitrogen (δ15N) isotope analyses of scaup egg components, female tissue, and local prey items. From arrival on the breeding grounds through the egg‐laying period, δ15N values of scaup red blood cells decreased while δ13C values became less variable; a pattern consistent with endogenous tissues equilibrating with local (freshwater) dietary sources. In 2006 and 2008, isotopic values for egg albumen and yolk protein indicated that most (>90%) protein used to produce these components was obtained on the breeding grounds. However, in 2007, a year with an exceptionally warm and dry spring, endogenous reserves contributed on average 41% of yolk and 29% of albumen. Results from this study suggest that female scaup can meet the protein needs of egg production largely from local dietary food sources. This highlights the importance of providing high‐quality breeding habitats for scaup. Whether this pattern holds in areas with similar breeding season lengths but longer migration routes, such as those found in the western boreal forest, should be investigated.

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Section: Methodsmentioning

confidence: 99%

“…Locations where waterfowl acquire protein and lipid for egg laying has long been debated (Ankney and MacInnes 1978, Ebbinge et al 1982, Davidson and Evans 1988, Bond et al 2007). Traditionally, nutrient dynamic studies have focused on a continuum to describe nutrient allocation to breeding activities.…”

mentioning

confidence: 99%

Endogenous contributions to egg protein formation in lesser scaup Aythya affinis

Cutting¹,

Hobson²,

Rotella³

et al. 2011

Journal of Avian Biology

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“…Potential elements affecting discrimination include taxon, growth rate, type of tissue, nutritional or reproductive status, reproductive strategy, differences in digestive physiology, the means of voiding nitrogenous waste, the macromolecular composition of sources (i.e., proportions of protein, carbohydrate, and lipid), and the extent and type of metabolic routing that dietary macromolecules undergo before integrating into tissues (i.e., from dietary protein to body protein or from dietary fat to body fat; Caut et al 2009;Borrell et al 2012;Kurle et al 2014). In birds, the isotopic discrimination occurring during reproduction has received attention, and differences have been observed between capital breeders, which rely on endogenous reserves, and income breeders, which rely on recently acquired nutrients (e.g., Klaassen et al 2001;Gauthier et al 2003;Hobson 2006;Langin et al 2006;Bond et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Influence of Reproduction on Stable-Isotope Ratios: Nitrogen and Carbon Isotope Discrimination between Mothers, Fetuses, and Milk in the Fin Whale, a Capital Breeder

Borrell

Gómez–Campos

Aguilar

2016

Physiological and Biochemical Zoology

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In mammals, the influence of gestation and lactation on the tissue stable-isotope ratios of females, fetuses, and milk remains poorly understood. Here we investigate the incidence of these events on δ(13)C and δ(15)N values in fin whales sampled off northwestern Spain between 1983 and 1985. The effect of gestation on tissue stable-isotope ratios was examined in the muscle of pregnant females (n = 13) and their fetuses (n = 10) and that of lactation in the muscle of nursing females (n = 21) and their milk (n = 25). Results suggest that fetuses are enriched compared to their mothers in both (15)N (Δ(15)N = 1.5‰) and (13)C (Δ(13)C =1.1‰), while, compared to muscle, milk is enriched in (15)N (Δ(15)N = 0.3‰) but depleted in (13)C (Δ(13)C = -0.62‰). This pattern is consistent with that previously observed for other species that, like the fin whale, rely on endogenous energy during reproduction, and it substantiates a general difference in the physiological processing of nitrogen and carbon balances between income and capital breeders. These findings are relevant to the understanding of the energetic balance of mammals during gestation and lactation and are central when inferences on trophic ecology are drawn from isotopic values of reproductive females.

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“…Under equilibrium conditions, stable isotope values in eggs differ in a predictable manner from those in the female's diet (Hobson 1995), but such discrimination values have not been established specifically for the mobilization of endogenous reserves to eggs. Researchers instead have used isotopic discrimination factors associated with the carnivore model of Hobson (1995) as a proxy for discrimination between endogenous reserves to eggs (Gauthier et al 2003, Schmutz et al 2006, Bond et al 2007). Discrimination between amphipod and abdominal lipids to yolk lipid formation was assumed to be 0.0‰ for δ 13 C (Hobson 1995).…”

Section: Methodsmentioning

confidence: 99%

Relative contribution of lipid sources to eggs of lesser scaup

Cutting

Hobson

Rotella

et al. 2013

Journal of Avian Biology

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Studies of how birds mobilize nutrients to eggs have traditionally considered a continuum of possible allocation strategies ranging from income breeding (rely on food sources found on the breeding grounds) to capital breeding (rely on body reserves stored prior to the breeding season). For capital breeding, stored body reserves can be acquired either on or away from the breeding grounds, but it has been difficult to quantify the relative contribution of each, precluding identification of key habitats for acquiring nutrients for clutch formation. During 2006-2009, we explored the importance of spring-staging habitats versus breeding-area habitats for egg-lipid formation in female lesser scaup Aythya affinis using stable carbon (d 13 C) isotope analyses. Although d 13 C values for abdominal lipid reserves brought to the breeding grounds overlapped those of local amphipods, we were able to quantify the importance of local plant carbohydrates (seeds of emergent wetland plants) to the production of eggs. We compared the importance of local wetland seeds (overall d 13 C: 229.1  0.9‰ SD) to combined lipid stores and lipids from local amphipods (overall d 13 C: 223.8  2.2‰). Local seeds and stored body lipids contributed equally to egg lipid formation across years but we found evidence of annual variation in their relative importance. Wetland seeds contributed 39% (SE  10%) to egg lipid production, and the importance of this source varied by year (90% CI  47-75% in 2006(90% CI  47-75% in , 13-42% in 2007(90% CI  47-75% in , 29-65% in 2008(90% CI  47-75% in , and 7-30% in 2009). In contrast to earlier studies that suggest lesser scaup predominantly employ a capital breeding strategy, our results suggest that in some years females may attain half of their energy for clutch formation from foods on the breeding grounds.

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Isotopic Evidence for Sources of Nutrients Allocated to Clutch Formation by Harlequin Ducks

Cited by 18 publications

References 33 publications

Endogenous contributions to egg protein formation in lesser scaup Aythya affinis

Endogenous contributions to egg protein formation in lesser scaup Aythya affinis

Influence of Reproduction on Stable-Isotope Ratios: Nitrogen and Carbon Isotope Discrimination between Mothers, Fetuses, and Milk in the Fin Whale, a Capital Breeder

Relative contribution of lipid sources to eggs of lesser scaup

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