scholarly journals Nest cover and faecal glucocorticoid metabolites are linked to hatching success and telomere length in breeding Common Eiders (Somateria mollissima)

2017 ◽  
Vol 95 (9) ◽  
pp. 695-703 ◽  
Author(s):  
K. Noreikiene ◽  
M. Öst ◽  
M.W. Seltmann ◽  
W. Boner ◽  
P. Monaghan ◽  
...  
Keyword(s):  
Telomere Length ◽  
Hatching Success ◽  
Prolonged Exposure ◽  
Somateria Mollissima ◽  
Faecal Glucocorticoid Metabolites ◽  
Common Eiders ◽  
Nesting Sites ◽  
Escape Responses ◽  
The Relationship ◽  
Perceived Predation Risk

Habitat-associated crypsis may affect perceived predation vulnerability, selecting for different predator avoidance strategies. Glucocorticoids could mediate the adjustment of escape responses to the extent of crypsis, introducing an overlooked source of variation in glucocorticoid–fitness relationships. However, prolonged exposure to elevated glucocorticoids may be costly, leading to accelerated telomere loss and, consequently, senescence. Here, we examined how nest cover and immunoreactive faecal glucocorticoid metabolite (fGCM) levels are linked to hatching success and telomere length in breeding female Common Eiders (Somateria mollissima (L., 1758)). We hypothesized that the degree of nest crypsis, reflecting differences in perceived predation risk, would moderate the relationship between reproductive success and fGCM levels. We also expected that telomere length would be shorter in birds with higher glucocorticoid concentration. Results showed that individuals with high fGCM levels had higher hatching success in nests with low cover, while low fGCM levels were more successful in well-concealed nests. We found that shorter telomeres were associated with high fGCM in nesting sites offering little cover and with low fGCM in well-concealed ones. This study provides the first evidence of habitat-dependent moderation of the relationships between stress physiology, telomere length and hatching success.

Intraclutch egg-size variation and hatching success in the common eider

1993 ◽  
Vol 71 (3) ◽  
pp. 544-549 ◽  
Author(s):  
Gregory J. Robertson ◽  
Fred Cooke
Keyword(s):  
Egg Size ◽  
Hatching Success ◽  
Size Variation ◽  
Hudson Bay ◽  
Somateria Mollissima ◽  
Physiological Mechanisms ◽  
Common Eiders ◽  
Laying Sequence ◽  
The Common ◽  
Nutrient Reserves

Intraclutch egg-size variation and hatching success were studied in a population of Hudson Bay common eiders (Somateria mollissima sedentaria) at La Pérouse Bay, Manitoba (58°24′N, 94°24′W), to test the hypothesis that females allocate more nutrient reserves to eggs that are more likely to hatch. Egg volumes were calculated for 575 known-sequence eggs in 134 complete clutches of 3–6 eggs. In general, the length of eggs decreased linearly with position in the laying sequence, whereas the breadth of eggs followed a curvilinear pattern, the second or third egg being the widest. For all clutch sizes, the last-laid egg was the smallest and the second- or third-laid egg the largest. Hatching success also varied with position in the laying sequence. Pre-incubation failure declined over the laying sequence, whereas hatching failure (dead, infertile, or rotten eggs) increased. In all cases pre-incubation failure was the major cause of egg loss (84% of total loss). Overall, third and fourth eggs were the most successful and first eggs were the least successful. With one exception, successful and unsuccessful eggs were the same size within a laying sequence. We conclude that there is no clear relationship between egg size and hatching success, and that laying sequence per se has a greater effect on hatching success. Female eiders do not appear to allocate more reserves to eggs that are most likely to hatch, and we consider other proximate, physiological mechanisms to explain the observed pattern of intraclutch egg-size variation.

scholarly journals Parental Investment Under Predation Threat in Incubating Common Eiders (Somateria mollissima): A Hormonal Perspective

2021 ◽  
Vol 9 ◽  
Author(s):  
Bertille Mohring ◽  
Frédéric Angelier ◽  
Kim Jaatinen ◽  
Charline Parenteau ◽  
Markus Öst
Keyword(s):  
Predation Risk ◽  
Body Condition ◽  
Parental Investment ◽  
Nest Predation ◽  
Hatching Success ◽  
Reproductive Investment ◽  
Somateria Mollissima ◽  
Common Eiders ◽  
Adaptation Hypothesis ◽  
The Impact

Predation risk affects the costs and benefits of prey life-history decisions. Predation threat is often higher during reproduction, especially in conspicuous colonial breeders. Therefore, predation risk may increase the survival cost of breeding, and reduce parental investment. The impact of predation risk on avian parental investment decisions may be hormonally mediated by prolactin and corticosterone, making them ideal tools for studying the trade-offs involved. Prolactin is thought to promote parental care and commitment in birds. Corticosterone is involved in allostasis and may either mediate reduced parental investment (corticosterone-fitness hypothesis), or promote parental investment through a reallocation of resources (corticosterone-adaptation hypothesis). Here, we used these hormonal proxies of incubation commitment to examine the impact of predation risk on reproduction in common eiders (Somateria mollissima) breeding in the Baltic Sea. This eider population is subject to high but spatially and temporally variable predation pressure on adults (mainly by the white-tailed eagle Haliaeetus albicilla and introduced mammalian predators) and nests (by the adult predators and exclusive egg predators such as hooded crows Corvus cornix). We investigated baseline hormonal levels and hatching success as a function of individual quality attributes (breeding experience, female and duckling body condition), reproductive investment (clutch weight), and predation risk. We expected individuals nesting in riskier environments (i.e., on islands where predation on adults or nests is higher, or in less concealed nests) to reduce their parental investment in incubation, reflected in lower baseline prolactin levels and either higher (corticosterone-fitness hypothesis) or lower (corticosterone-adaptation hypothesis) baseline corticosterone levels. Contrary to our predictions, prolactin levels showed a positive correlation with nest predation risk. The unexpected positive relationship could result from the selective disappearance of low-quality females (presumably having low prolactin levels) from risky sites. Supporting this notion, female body condition and hatching success were positively correlated with predation risk on females, and baseline prolactin concentrations were positively correlated with duckling body condition, a proxy of maternal quality. In line with the corticosterone-adaptation hypothesis, baseline corticosterone levels increased with reproductive investment, and were negatively associated with nest predation risk. Hatching success was lower on islands where nest predation risk was higher, consistent with the idea of reduced reproductive investment under increased threat. Long-term individual-based studies are now needed to distinguish selection processes occurring at the population scale from individually plastic parental investment in relation to individual quality and variable predation risk.

scholarly journals Glucocorticoids, state-dependent reproductive investment and success in the face of danger in a long-lived bird

2020 ◽  
Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst
Keyword(s):  
Predation Risk ◽  
Telomere Length ◽  
Clutch Size ◽  
Body Condition ◽  
Nest Predation ◽  
Hatching Success ◽  
Reproductive Investment ◽  
Trade Off ◽  
Relative Telomere Length ◽  
Future Reproduction

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.

scholarly journals Factors influencing the occurrence of negative interactions between people and crocodilians in Mexico

Oryx ◽  
2021 ◽  
pp. 1-9
Author(s):  
Giovany Arturo González-Desales ◽  
Luis Sigler ◽  
Jesús García-Grajales ◽  
Pierre Charruau ◽  
Martha Mariela Zarco-González ◽  
...  
Keyword(s):  
Anthropogenic Activities ◽  
Biosphere Reserve ◽  
Rigorous Evaluation ◽  
Caiman Crocodilus ◽  
Crocodylus Acutus ◽  
American Crocodile ◽  
Nesting Sites ◽  
The Relationship ◽  
Nesting Season ◽  
Negative Interactions

Abstract Negative interactions between people and crocodilians have increased worldwide, but in Mexico there have been few systematic reports and no rigorous evaluation of this problem. We compiled information on negative interactions between people and the spectacled caiman Caiman crocodilus and American crocodile Crocodylus acutus from the Worldwide Crocodilian Attack Database for 1993–2018, and we investigated interactions in greater depth, through interviews with people in La Encrucijada Biosphere Reserve. We examined the relationship between the occurrence of negative interactions between people and C. acutus and the species' nesting season and abundance, and presence records. In Mexico, the frequency of negative interactions increases when anthropogenic activities occur close to nesting sites (< 30 km) and during the nesting season (February–September). In La Encrucijada, following negative interactions with crocodiles, the local inhabitants killed 30 crocodiles measuring > 2.5 m long in 2011–2012. The frequency of negative human–crocodilian interactions was not correlated with the abundance of crocodilians but was correlated with the number of presence records of crocodiles. Strategies to minimize these interactions include warnings at nesting sites, increased monitoring of anthropogenic activities during the nesting season, and management of nests to prevent them being destroyed by people.

scholarly journals Herd immunity drives the epidemic fadeout of avian cholera in Arctic-nesting seabirds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jacintha G. B. van Dijk ◽  
Samuel A. Iverson ◽  
H. Grant Gilchrist ◽  
N. Jane Harms ◽  
Holly L. Hennin ◽  
...  
Keyword(s):  
Colony Size ◽  
Pasteurella Multocida ◽  
Herd Immunity ◽  
Reproductive Number ◽  
Somateria Mollissima ◽  
Common Eiders ◽  
Serological Status ◽  
Antibody Titers ◽  
Avian Cholera

AbstractAvian cholera, caused by the bacterium Pasteurella multocida, is a common and important infectious disease of wild birds in North America. Between 2005 and 2012, avian cholera caused annual mortality of widely varying magnitudes in Northern common eiders (Somateria mollissima borealis) breeding at the largest colony in the Canadian Arctic, Mitivik Island, Nunavut. Although herd immunity, in which a large proportion of the population acquires immunity to the disease, has been suggested to play a role in epidemic fadeout, immunological studies exploring this hypothesis have been missing. We investigated the role of three potential drivers of fadeout of avian cholera in eiders, including immunity, prevalence of infection, and colony size. Each potential driver was examined in relation to the annual real-time reproductive number (Rt) of P. multocida, previously calculated for eiders at Mitivik Island. Each year, colony size was estimated and eiders were closely monitored, and evaluated for infection and serological status. We demonstrate that acquired immunity approximated using antibody titers to P. multocida in both sexes was likely a key driver for the epidemic fadeout. This study exemplifies the importance of herd immunity in influencing the dynamics and fadeout of epidemics in a wildlife population.

Body and organ mass dynamics during remigial moult in a wing–foot-propelled diving sea duck: the Common Eider (Atlantic) (Somateria mollissima dresseri)

2015 ◽  
Vol 93 (10) ◽  
pp. 755-764 ◽  
Author(s):  
A. Viain ◽  
M. Guillemette ◽  
J.-P.L. Savard
Keyword(s):  
Muscle Mass ◽  
Body Mass ◽  
Flight Muscle ◽  
Somateria Mollissima ◽  
Dabbling Ducks ◽  
Diving Ducks ◽  
Common Eiders ◽  
Sea Duck ◽  
Remigial Moult ◽  
Atrophy Of The Heart

Body and organ dynamics, during remigial moult, have been mainly explored on geese, dabbling ducks, and foot-propelled diving ducks, but weakly on sea ducks. This study investigated the internal changes in a wing–foot-propelled sea duck to determine the adaptive strategies implemented. Forty-five male Common Eiders (Atlantic) (Somateria mollissima dresseri Sharpe, 1871), collected in the Gulf of St. Lawrence, were dissected; their body mass, muscle mass, and organ sizes were measured. We tested three hypotheses: (1) S. m. dresseri use a strategic reduction of body mass to reduce the flightlessness duration; (2) organs will exhibit changes consistent with a trade-off between function and maintenance to save and reallocate energy and proteins to feather growth; (3) S. m. dresseri would show lower flight muscle reduction than foot-propelled diving ducks. Somateria mollissima dresseri did not lose body mass, which does not support the first hypothesis. Atrophy of the heart followed by hypertrophy and opposite changes in leg muscle mass and gizzard mass are consistent with the second hypothesis. Flight muscle mass showed lower variations than in other ducks, validating the third hypothesis. We also suggest that the lipid depletion observed early in the moult could be a strategy to reduce foraging effort and minimize the risk of damaging the growing feathers.

Clutch quality is related to embryonic development duration, hatchling body size and telomere length in the spined toad (Bufo spinosus)

2021 ◽  
Vol 133 (1) ◽  
pp. 135-142
Author(s):  
Marion Cheron ◽  
Frédéric Angelier ◽  
Cécile Ribout ◽  
François Brischoux
Keyword(s):  
Reproductive Success ◽  
Embryonic Development ◽  
Parental Care ◽  
Telomere Length ◽  
Mate Selection ◽  
Hatching Success ◽  
Egg Quality ◽  
Parental Quality ◽  
Complex Interactions ◽  
Development Duration

Abstract Reproductive success is often related to parental quality, a parameter expressed through various traits, such as site selection, mate selection and energetic investment in the eggs or progeny. Owing to the complex interactions between environmental and parental characteristics occurring at various stages of the reproductive event, it is often complicated to tease apart the relative contributions of these different factors to reproductive success. Study systems where these complex interactions are simplified (e.g. absence of parental care) can help us to understand how metrics of parental quality (e.g. gamete and egg quality) influence reproductive success. Using such a study system in a common garden experiment, we investigated the relationships between clutch hatching success (a proxy of clutch quality) and offspring quality in an amphibian species lacking post-oviposition parental care. We found a relationship between clutch quality and embryonic development duration and hatchling phenotype. We found that hatchling telomere length was linked to hatching success. These results suggest that clutch quality is linked to early life traits in larval amphibians and that deciphering the influence of parental traits on the patterns we detected is a promising avenue of research.

Prolonged Exposure to Political Violence and the Development of Post-Traumatic Stress Symptoms in Palestinian Adolescents

2020 ◽  
pp. 189-220
Author(s):  
Muhammad M. Haj-Yahia ◽  
Charles W. Greenbaum
Keyword(s):  
Political Violence ◽  
Parenting Styles ◽  
Traumatic Stress ◽  
Protective Factor ◽  
Prolonged Exposure ◽  
Negative Evaluation ◽  
Post Traumatic Stress ◽  
Stress Symptoms ◽  
Post Traumatic ◽  
The Relationship

This chapter investigates the relationship between prolonged exposure to political violence (EPV) and post-traumatic stress symptoms (PTSS) among Palestinian adolescents. It also examines the moderating effect of participants’ age, gender, and parental socialization styles on the relationship between EPV and PTSS. A systematic cluster random sample of 2,934 Palestinian adolescents aged 14 to 19 years living in the West Bank and East Jerusalem responded to self-administered questionnaires. Multiple regression analysis showed a positive relationship between levels of EPV and of PTSS. Girls showed higher levels of PTSS than boys. Hostile and rejecting parenting styles, strict discipline, and negative evaluation from parents correlated positively with high PTSS, whereas intimate and loving parenting correlated with low levels of PTSS, supporting the hypotheses presented here. The chapter discusses the importance of intimate and loving parenting styles as a possible protective factor for mitigating the effects of political violence on children.

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