scholarly journals Cause or consequence? Exploring the role of phenotypic plasticity and genetic polymorphism in the emergence of phenotypic spatial patterns of the European eel

2017 ◽  
Vol 74 (7) ◽  
pp. 987-999 ◽  
Author(s):  
Maria Mateo ◽  
Patrick Lambert ◽  
Stéphane Tetard ◽  
Martin Castonguay ◽  
Bruno Ernande ◽  
...  
Keyword(s):  
Life History ◽  
Phenotypic Plasticity ◽  
Habitat Selection ◽  
Life History Traits ◽  
Environmental Variability ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Anthropogenic Pressures ◽  
The Impact

The European eel (Anguilla anguilla), and generally, temperate eels, are relevant species for studying adaptive mechanisms to environmental variability because of their large distribution areas and their limited capacity of local adaptation. In this context, GenEveel, an individual-based optimization model, was developed to explore the role of adaptive phenotypic plasticity and genetic-dependent habitat selection, in the emergence of observed spatial life-history traits patterns for eels. Results suggest that an interaction of genetically and environmentally controlled growth may be the basis for genotype-dependent habitat selection, whereas plasticity plays a role in changes in life-history traits and demographic attributes. Therefore, this suggests that those mechanisms are responses to address environmental heterogeneity. Moreover, this brings new elements to explain the different life strategies of males and females. A sensitivity analysis showed that the parameters associated with the optimization of fitness and growth genotype were crucial in reproducing the spatial life-history patterns. Finally, it raises the question of the impact of anthropogenic pressures that can cause direct mortalities but also modify demographic traits and act as a selection pressure.

Variability of breeding resource partitioning in a lacertid lizard at field scale

2017 ◽  
Vol 67 (2) ◽  
pp. 81-92
Author(s):  
Marta Biaggini ◽  
Claudia Corti
Keyword(s):  
Life History ◽  
Human Activities ◽  
Life History Traits ◽  
Environmental Variability ◽  
Egg Mass ◽  
Life History Variation ◽  
Field Scale ◽  
Starting Point ◽  
Intensively Managed ◽  
The Impact

Human activities cause increasingly deep alterations to natural environments. Yet, the effects on vertebrates with low dispersal capacity are still poorly investigated, especially at field scale. Life history variation represents one means by which species can adapt to a changing environment. Among vertebrates, lizards exhibit a high degree of variation in life-history traits, often associated with environmental variability. We examined the female breeding output ofPodarcissiculus(Lacertidae) inside agricultural habitats, to test whether different cultivation and management influence the life-history traits of this species. Interestingly, we recorded variability of female breeding output at a very fine scale, namely among adjacent vineyards and olive orchards under different management levels. Lizards displayed the lowest breeding effort in the almost unmanaged sites, while clutch mass, relative fecundity and mean egg mass slightly increased in more intensively managed sites. However, in the most intensive cultivations we detected a life-history trade-off, where eggs from larger clutches tended to be relatively smaller than eggs from smaller clutches. This pattern suggests that agriculture can influence lizard reproductive output, partly favouring it in the presence of medium intensity cultivation but causing, in the most intensively managed sites, some environmental constraints that require a peculiar partitioning of the breeding resources. Even though further studies are needed to clarify the mechanisms driving the observed pattern, our results can be considered a starting point for evaluating the analysis of lizard breeding features as a tool to assess the impact of human activities, at least in agricultural environments.

scholarly journals Fecundity of silver-phase eels (Anguilla anguilla) from different habitat types and geographic locations

2015 ◽  
Vol 73 (1) ◽  
pp. 135-141 ◽  
Author(s):  
Ruairí MacNamara ◽  
T. Kieran McCarthy ◽  
Håkan Wickström ◽  
Patrik D. Clevestam
Keyword(s):  
Life History ◽  
Body Size ◽  
Baltic Sea ◽  
Life History Traits ◽  
Geographic Origin ◽  
Habitat Type ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Habitat Types ◽  
Geographic Locations

Abstract The reproductive ecology of European eel (Anguilla anguilla) is poorly understood, though information on life-history traits such as fecundity is necessary for appropriate management of this critically endangered species. During the growth period of the life cycle, yellow-phase eels can be resident in different habitat types (e.g. salinity ranging from freshwater to marine) over a wide geographic distribution. Consequently, maturing silver-phase eels migrating back to the oceanic spawning grounds can display considerable variation in certain life-history traits depending on their habitat and/or geographic origin. Few fecundity estimates are available from wild A. anguilla, and no investigation of the effects of habitat type (i.e. salinity) or geographic location on variation in fecundity has been undertaken. To assess the former, we examined silver-phase eels which had predominantly been resident in freshwater (Lake Mälaren, Sweden) or brackish (Baltic Sea) habitats. Despite Lake Mälaren eels generally being larger, there was no difference in the fecundity–body size relationship between these salinity zones. Second, we determined if fecundity differed between silver-phase eels sampled from different geographic locations: Lake Mälaren and the Baltic Sea outlet in Sweden, the River Shannon in Ireland (northwest Europe) and Vistonis Lake in Greece (eastern Mediterranean). Our results showed that silver-phase eels from Sweden (Lake Mälaren and Baltic Sea outlet) and Greece were significantly more fecund at a given body size than those from Ireland. Spawner models and conservation policies should therefore take account of eel geographic origin in particular when incorporating this life-history parameter.

Hormones and Behavior

2019 ◽  
pp. 11-26
Author(s):  
Maren N. Vitousek ◽  
Laura A. Schoenle
Keyword(s):  
Life History ◽  
Life Histories ◽  
Life History Traits ◽  
Developmental Plasticity ◽  
Endocrine System ◽  
Phenotypic Traits ◽  
Social Environments ◽  
Trade Offs ◽  
And Behavior

Hormones mediate the expression of life history traits—phenotypic traits that contribute to lifetime fitness (i.e., reproductive timing, growth rate, number and size of offspring). The endocrine system shapes phenotype by organizing tissues during developmental periods and by activating changes in behavior, physiology, and morphology in response to varying physical and social environments. Because hormones can simultaneously regulate many traits (hormonal pleiotropy), they are important mediators of life history trade-offs among growth, reproduction, and survival. This chapter reviews the role of hormones in shaping life histories with an emphasis on developmental plasticity and reversible flexibility in endocrine and life history traits. It also discusses the advantages of studying hormone–behavior interactions from an evolutionary perspective. Recent research in evolutionary endocrinology has provided insight into the heritability of endocrine traits, how selection on hormone systems may influence the evolution of life histories, and the role of hormonal pleiotropy in driving or constraining evolution.

Impact of age, size, and sex on adult black soldier fly [Hermetia illucens L. (Diptera: Stratiomyidae)] thermal preference

2021 ◽  
pp. 1-12
Author(s):  
N.F. Addeo ◽  
C. Li ◽  
T.W. Rusch ◽  
A.J. Dickerson ◽  
A.M. Tarone ◽  
...  
Keyword(s):  
Life History ◽  
Thermal Gradient ◽  
Life History Traits ◽  
Animal Feed ◽  
Mass Rearing ◽  
Thermal Preference ◽  
Black Soldier Fly ◽  
Hermetia Illucens ◽  
Surface Temperatures ◽  
The Impact

Population growth and rapid urbanisation have increased the global demand for animal feed and protein sources. Therefore, traditional animal feed production should be increased through the use of alternative nutrient sources. Insects as feed are beginning to fill this need. One such insect is the black soldier fly, Hermetia illucens L. (Diptera: Stratiomyidae). However, to more effectively mass produce the black soldier fly, a better understanding of its thermal biology is needed. Thus, the aim of this study was to evaluate the impact of age, size, and sex on adult black soldier fly thermal preference. The thermal preference of adult black soldier flies was determined by exposing flies to a thermal gradient with a range of surface temperatures and monitoring their positions over time. An aluminium plate was used to create a linear thermal gradient where surface temperatures ranged from ~15-60 °C. Flies were distinguished by age (1-d-post-emergence vs 7-d-post-emergence), size (large vs small) and sex (male vs female) to assess whether thermal preference differed by specific life-history traits. Thermal preference for 7-d-post-emergence adults was significantly lower (19.2 °C) than 1-d-post-emergence adults (28.7 °C), respectively. Similarly, small adults selected significantly cooler (21.1 °C) temperatures than large adults (26.9 °C). No significant differences in thermal preferences were found between sex, regardless of age or size. In fact, males and females had similar thermal preference of 23.8 and 24.2 °C, respectively. This study reveals that multiple life-history traits of adult black soldier fly affect their thermal preference, and thus should be taken into consideration by mass rearing facilities to optimize production.

scholarly journals The Ecology of Stress: linking life-history traits with physiological control mechanisms in free-living guanacos

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2640 ◽  
Author(s):  
Ramiro J.A. Ovejero Aguilar ◽  
Graciela A. Jahn ◽  
Mauricio Soto-Gamboa ◽  
Andrés J. Novaro ◽  
Pablo Carmanchahi
Keyword(s):  
Life History ◽  
Seasonal Variation ◽  
Reproductive Success ◽  
Hpa Axis ◽  
Life History Traits ◽  
Mating Period ◽  
Entire Study ◽  
Non Invasive ◽  
Animal Populations

BackgroundProviding the context for the evolution of life-history traits, habitat features constrain successful ecological and physiological strategies. In vertebrates, a key response to life’s challenges is the activation of the Stress (HPA) and Gonadal (HPG) axes. Much of the interest in stress ecology is motivated by the desire to understand the physiological mechanisms in which the environment affects fitness. As reported in the literature, several intrinsic and extrinsic factors affect variability in hormone levels. In both social and non-social animals, the frequency and type of interaction with conspecifics, as well as the status in social species, can affect HPA axis activity, resulting in changes in the reproductive success of animals. We predicted that a social environment can affect both guanaco axes by increasing the secretion of testosterone (T) and Glucocorticoid (GCs) in response to individual social interactions and the energetic demands of breeding. Assuming that prolonged elevated levels of GCs over time can be harmful to individuals, it is predicted that the HPA axis suppresses the HPG axis and causes T levels to decrease, as GCs increase.MethodsAll of the data for individuals were collected by non-invasive methods (fecal samples) to address hormonal activities. This is a novel approach in physiological ecology because feces are easily obtained through non-invasive sampling in animal populations.ResultsAs expected, there was a marked adrenal (p-value = .3.4e−12) and gonadal (p-value = 0.002656) response due to seasonal variation inLama guanicoe. No significant differences were found in fecal GCs metabolites between males/females*season for the entire study period (p-value = 0.2839). Despite the seasonal activity variation in the hormonal profiles, our results show a positive correlation (p-value = 1.952e−11, COR = 0.50) between the adrenal and gonadal system. The marked endocrine (r2 = 0.806) and gonad (r2 = 0.7231) response due to seasonal variation in male guanaco individuals highlights the individual’s energetic demands according to life-history strategies. This is a remarkable result because no inhibition was found between the axes as theory suggests. Finally, the dataset was used to build a reactive scope model for guanacos.DiscussionGuanacos cope with the trade-off between sociability and reproductive benefits and costs, by regulating their GCs and T levels on a seasonal basis, suggesting an adaptive role of both axes to different habitat pressures. The results presented here highlight the functional role of stress and gonad axes on a critical phase of a male mammal’s life—the mating period—when all of the resources are at the disposal of the male and must be used to maximize the chances for reproductive success.

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