Fluctuating feather asymmetry in relation to corticosterone levels is sex-dependent in Eurasian treecreeper (Certhia familiaris) nestlings

Helle, Samuli; Suorsa, Petri; Huhta, Esa; Hakkarainen, Harri

doi:10.1098/rsbl.2009.1068

“…A similar pattern may be present in protogynous reef fish, where males frequently undergo a period of rapid growth following sex change (Munday et al 2009, Walker andMcCormick 2004). This finding corroborates other studies that detected sex-dependent FA and suggested it was driven by sex-specific growth and energy demands in a species of fly (Bonduriansky 2009) and bird (Helle et al 2010), but an in depth literature review revealed no other studies demonstrating sex-specific FA in otoliths of fishes. As males tended to be more asymmetric than females in this study, greater FA at Wahine Park could be explained by the higher proportion of males to females relative to Kau Bay (Chapter 2).…”

Section: Fluctuating Asymmetry Sex and Sizesupporting

confidence: 90%

“…Studies of FA are problematic because the asymmetry can be expressed in some traits and not others (Blanckenhorn et al 1998, Woods et al 1999 and the magnitude of asymmetry can depend on the type of stress encountered (Campbell et al 1998, Roy andStanton 1999). Furthermore, FA may be reduced in males in populations where females actively select mates (Kodric-brown 1997, Møller 1994 or increased in males due to sex-specific differences in energy demands (Helle et al 2010, Serrano et al 2008. Thus, the ability to detect FA can depend on a thorough understanding of the stress-and sex-specific development of FA in the particular trait examined (Lens et al 2002, Palmer andStrobeck 2003).…”

Section: Introductionmentioning

confidence: 99%

Reproductive Ecology, Condition, and the Physical Environment of a Temperate Protogynous Hermaphrodite at a Small Scale

Oliver¹

0

View full text Add to dashboard Cite

Hermaphroditic reef fish display remarkable diversity in mating strategies, social structure, and the timing of sex change. Understanding spatial variation in reproductive ecology and physiological condition is important in the design of marine reserve systems and fisheries management for species that change sex. I investigated patterns in reproductive ecology, condition, and the influence of the underlying physical environment, for a temperate protogynous (female first) hermaphrodite, the spotty (Notolabrus celidotus) at a small spatial scale. First, I used SCUBA surveys to visually estimate density, sex ratio, and size-frequency to describe the social structure of two populations of spotties located at either end of a 9 km gradient in swell exposure. I then collected individuals from both locations to estimate growth, mortality, and the timing of maturation and sex change for each population. To estimate and compare physiological stress and condition of individuals sampled from these two locations, I used otoliths to quantify fluctuating asymmetry (a measure of stress) and I compared this to other commonly used condition indices. Lastly, I estimated spatial variation in social structure and a set of environmental variables at 30 sites along a gradient of swell exposure to investigate correlations between the physical environment and the density, sex ratio, and size-frequency of spotties. The results revealed that social structure differed markedly between two populations but not always as expected. A low ratio of males to females in sheltered Kau Bay suggested that the rate of sex change was constrained for this population (relative to Wahine Park, a more swell-exposed site, where males were more abundant in the population). Individuals from Kau Bay exhibited slower growth and higher mortality estimates, and in line with predictions of the size advantage model, females appeared to change sex at an early age and smaller size relative to Wahine Park. Contrary to expectations, however, low levels of fluctuating asymmetry suggested the population at Kau Bay was less stressed than Wahine Park, despite evidence for reduced physiological condition (Fulton’s condition factor K) and high density at Kau Bay. Differences in fluctuating asymmetry between sexes and size classes suggested that sex-specific fluctuating asymmetry and stressors later in the life history are important in these populations. Furthermore, correlations between social structure and the physical environment were inconclusive and highlight the necessity for large sampling efforts. Overall, this study concludes that availability of spawning-territory may limit the rate of sex change and influence reproductive potential in this species. This process may be applicable to other protogynous species that rely on territory-defense as a mating strategy. Sex-specific expression of fluctuating asymmetry should be considered in hermaphroditic reef fish and the impact of stressors acting on specific stages in the life history of individuals requires further investigation. Furthermore, my results suggest that condition indices and fluctuating asymmetry cannot be used interchangeably to estimate health for these populations (the metrics may provide complementary information). Overall, these results emphasise complex and variable patterns in the reproductive ecology of hermaphroditic species and my work is among the first to demonstrate such patterns over a small spatial scale. Further work can clarify questions raised in this study and benefit the conservation of hermaphroditic reef fish.

show abstract

“…Similarly, corticosterone or cortisol treatment, either through the mother or directly into the egg, has resulted in increased FA in hatchlings in chickens, Japanese quails and damselfish [23][24][25]. In a free-living species, high corticosterone levels were related to elevated FA levels of male nestlings in tree creepers [26]. These studies-albeit being very relevant as such-were not designed to study maternal stress as the cortisol/corticosterone was administered directly, without challenging the mothers in some way.…”

Section: Introductionmentioning

confidence: 99%

Maternal Stress Affects Fetal Growth but Not Developmental Instability in Rabbits

Bots

¹

,

Breno

²

,

Schaepdrijver

³

et al. 2016

View full text Add to dashboard Cite

Developmental instability (DI), often measured by fluctuating asymmetry (FA) or the frequency of phenodeviants (fPD), is thought to increase with stress. However, specifically for stressors of maternal origin, evidence of such negative associations with DI is scarce. Whereas effects of maternal stress on DI have predominately been examined retroactively in humans, very little is known from experiments with well-defined stress levels in animal model systems. The aim of this study was to examine the effects of maternal exposure to three doses (plus a control) of a toxic compound affecting maternal condition on DI of their offspring in rabbits. Presence of maternal stress induced by the treatment was confirmed by a decrease in food consumption and weight gain of gravid females in the medium and high dose. Major abnormalities and mortality were unaffected by dose, suggesting the lack of toxic effects of the compound on the offspring. In spite of string maternal stress, offspring FA did not increase with dose. The treatment did lead to elevated fPD, but most were transient, reflecting growth retardation. Furthermore, a consistent association between fPD and FA was absent. These findings indicate that DI is not increased by maternal stress in this animal model.

show abstract

“…Studies of FA are problematic because the asymmetry can be expressed in some traits and not others (Blanckenhorn et al 1998, Woods et al 1999 and the magnitude of asymmetry can depend on the type of stress encountered (Campbell et al 1998, Roy andStanton 1999). Furthermore, FA may be reduced in males in populations where females actively select mates (Kodric-brown 1997, Møller 1994 or increased in males due to sex-specific differences in energy demands (Helle et al 2010, Serrano et al 2008. Thus, the ability to detect FA can depend on a thorough understanding of the stress-and sex-specific development of FA in the particular trait examined (Lens et al 2002, Palmer andStrobeck 2003).…”

Section: Introductionmentioning

confidence: 99%

Reproductive Ecology, Condition, and the Physical Environment of a Temperate Protogynous Hermaphrodite at a Small Scale

Oliver¹

0

View full text Add to dashboard Cite

Hermaphroditic reef fish display remarkable diversity in mating strategies, social structure, and the timing of sex change. Understanding spatial variation in reproductive ecology and physiological condition is important in the design of marine reserve systems and fisheries management for species that change sex. I investigated patterns in reproductive ecology, condition, and the influence of the underlying physical environment, for a temperate protogynous (female first) hermaphrodite, the spotty (Notolabrus celidotus) at a small spatial scale. First, I used SCUBA surveys to visually estimate density, sex ratio, and size-frequency to describe the social structure of two populations of spotties located at either end of a 9 km gradient in swell exposure. I then collected individuals from both locations to estimate growth, mortality, and the timing of maturation and sex change for each population. To estimate and compare physiological stress and condition of individuals sampled from these two locations, I used otoliths to quantify fluctuating asymmetry (a measure of stress) and I compared this to other commonly used condition indices. Lastly, I estimated spatial variation in social structure and a set of environmental variables at 30 sites along a gradient of swell exposure to investigate correlations between the physical environment and the density, sex ratio, and size-frequency of spotties. The results revealed that social structure differed markedly between two populations but not always as expected. A low ratio of males to females in sheltered Kau Bay suggested that the rate of sex change was constrained for this population (relative to Wahine Park, a more swell-exposed site, where males were more abundant in the population). Individuals from Kau Bay exhibited slower growth and higher mortality estimates, and in line with predictions of the size advantage model, females appeared to change sex at an early age and smaller size relative to Wahine Park. Contrary to expectations, however, low levels of fluctuating asymmetry suggested the population at Kau Bay was less stressed than Wahine Park, despite evidence for reduced physiological condition (Fulton’s condition factor K) and high density at Kau Bay. Differences in fluctuating asymmetry between sexes and size classes suggested that sex-specific fluctuating asymmetry and stressors later in the life history are important in these populations. Furthermore, correlations between social structure and the physical environment were inconclusive and highlight the necessity for large sampling efforts. Overall, this study concludes that availability of spawning-territory may limit the rate of sex change and influence reproductive potential in this species. This process may be applicable to other protogynous species that rely on territory-defense as a mating strategy. Sex-specific expression of fluctuating asymmetry should be considered in hermaphroditic reef fish and the impact of stressors acting on specific stages in the life history of individuals requires further investigation. Furthermore, my results suggest that condition indices and fluctuating asymmetry cannot be used interchangeably to estimate health for these populations (the metrics may provide complementary information). Overall, these results emphasise complex and variable patterns in the reproductive ecology of hermaphroditic species and my work is among the first to demonstrate such patterns over a small spatial scale. Further work can clarify questions raised in this study and benefit the conservation of hermaphroditic reef fish.

show abstract

Fluctuating feather asymmetry in relation to corticosterone levels is sex-dependent in Eurasian treecreeper (Certhia familiaris) nestlings

Cited by 6 publications

References 24 publications

Reproductive Ecology, Condition, and the Physical Environment of a Temperate Protogynous Hermaphrodite at a Small Scale

Reproductive Ecology, Condition, and the Physical Environment of a Temperate Protogynous Hermaphrodite at a Small Scale

Maternal Stress Affects Fetal Growth but Not Developmental Instability in Rabbits

Reproductive Ecology, Condition, and the Physical Environment of a Temperate Protogynous Hermaphrodite at a Small Scale

Contact Info

Product

Resources

About