scholarly journals Time spent in distinct life-history stages has sex-specific effects on reproductive fitness in wild Atlantic salmon

2019 ◽  
Author(s):  
Kenyon B. Mobley ◽  
Hanna Granroth-Wilding ◽  
Mikko Ellmen ◽  
Panu Orell ◽  
Jaakko Erkinaro ◽  
...  
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Atlantic Salmon ◽  
Marine Environment ◽  
Mating Success ◽  
Life History Theory ◽  
Reproductive Fitness ◽  
Life Cycles ◽  
Male Mating ◽  
Life History Stages

AbstractIn species with complex life cycles, life history theory predicts that fitness is affected by conditions encountered in previous life history stages. Here, we use a four-year pedigree to investigate if time spent in two distinct life history stages has sex-specific reproductive fitness consequences in anadromous Atlantic salmon (Salmo salar). We determined the amount of years spent in fresh water as juveniles (freshwater age, FW), and years spent in the marine environment prior to sexual maturation (sea age, SW) on 264 spawning adults. We then estimated reproductive fitness as the number of offspring (reproductive success) and the number of mates (mating success) using genetic parentage analysis (>5000 offspring). Sea age is positively correlated with reproductive and mating success of both sexes whereby older and larger individuals gained the highest reproductive fitness benefits (females: increase of 16.5 offspring/SW and 0.86 mates/SW; males: increase of 12.4 offspring/SW and 0.43 mates/SW). Younger freshwater age was related to older sea age and thus increased reproductive fitness, but only among females (females: −9.0 offspring/FW and −0.80 mates/FW). This implies that females can obtain higher reproductive fitness by transitioning to the marine environment earlier. In contrast, male mating and reproductive success was unaffected by freshwater age and males returned to spawn earlier than females despite the fitness advantage of later sea age maturation. Our results show that the timing of transitions between juvenile and adult phases has a sex-specific consequence on female reproductive fitness, demonstrating a life-history trade-off between maturation and reproduction in wild Atlantic salmon.

scholarly journals Time spent in distinct life history stages has sex‐specific effects on reproductive fitness in wild Atlantic salmon

2020 ◽  
Vol 29 (6) ◽  
pp. 1173-1184 ◽  
Author(s):  
Kenyon B. Mobley ◽  
Hanna Granroth‐Wilding ◽  
Mikko Ellmén ◽  
Panu Orell ◽  
Jaakko Erkinaro ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Reproductive Fitness ◽  
Life History Stages ◽  
Specific Effects

scholarly journals Male competition and the evolution of mating and life-history traits in experimental populations of Aedes aegypti

2019 ◽  
Vol 286 (1904) ◽  
pp. 20190591 ◽  
Author(s):  
Alima Qureshi ◽  
Andrew Aldersley ◽  
Brian Hollis ◽  
Alongkot Ponlawat ◽  
Lauren J. Cator
Keyword(s):  
Life History ◽  
Aedes Aegypti ◽  
Mating Success ◽  
Life History Traits ◽  
Male Competition ◽  
Male Mating ◽  
Male Mating Success ◽  
Reproductive Control ◽  
Evolutionary Response ◽  
Mating Conditions

Aedes aegypti is an important disease vector and a major target of reproductive control efforts. We manipulated the opportunity for sexual selection in populations of Ae . aegypti by controlling the number of males competing for a single female. Populations exposed to higher levels of male competition rapidly evolved higher male competitive mating success relative to populations evolved in the absence of competition, with an evolutionary response visible after only five generations. We also detected correlated evolution in other important mating and life-history traits, such as acoustic signalling, fecundity and body size. Our results indicate that there is ample segregating variation for determinants of male mating competitiveness in wild populations and that increased male mating success trades-off with other important life-history traits. The mating conditions imposed on laboratory-reared mosquitoes are likely a significant determinant of male mating success in populations destined for release.

Diet, Nutrition, and Disease across the Lifespan

2018 ◽  
Author(s):  
Stanley J. Ulijaszek
Keyword(s):  
Life History ◽  
Life History Theory ◽  
Human Life ◽  
Human Growth ◽  
Child Growth ◽  
Reproductive Age ◽  
Life History Stages ◽  
Available Energy ◽  
Ecological Success ◽  
Exclusive Processes

Diet and nutrition need to be adequate to sustain human growth, sexual maturation, reproduction, and the physical labour needed to obtain food and support the successful maturation of offspring to reproductive age. This chapter examines human diet and nutrition as they relate to infectious disease experience, and how nutrition and infection influence the human life course, which is organized according to life history stages. Human life history theory organizes growth and reproduction into largely exclusive processes: available energy goes first into the former, and then, after puberty, into the latter. Human life history is extremely plastic, with child growth, onset of sexual maturity, fecundity and longevity all being sensitive to nutrition. Such plasticity has been fundamental to human ecological success and it is important to understand it to be able to interpret evidence for biological quality of life among past populations.

Examining the link between religiousness and fitness in a behavioural ecological framework

2019 ◽  
Vol 52 (5) ◽  
pp. 756-767 ◽  
Author(s):  
Janko Međedović
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Parental Investment ◽  
Life History Theory ◽  
Community Sample ◽  
Future Research ◽  
Harsh Environment ◽  
Age At First Birth ◽  
First Birth ◽  
Number Of Children

AbstractIn recent years there have been attempts to explain religiousness from an evolutionary viewpoint. However, empirical data on this topic are still lacking. In the present study, the behavioural ecological theoretical framework was used to explore the relations between religiousness, harsh environment, fitness (reproductive success and parental investment) and fitness-related outcomes (age at first birth, desired number of children and the romantic relationship duration). The data were collected from 461 individuals from a community sample who were near the end of their reproductive phase (54% females, Mage = 51.75; SD = 6.56). Positive links between religiousness, harsh environment, fitness and fitness-related outcomes were expected, with the exception of age at first birth, for which a negative association was hypothesized. Hence, the main assumption of the study was that religiousness has some attributes of fast life-history phenotypes – that it emerges from a harsh environment and enables earlier reproduction. The study findings partially confirmed these hypotheses. Religiousness was positively related to environmental harshness but only on a zero-order level. Religious individuals had higher reproductive success (this association was especially pronounced in males) but religiousness did not show associations with parental investment. Religiousness was positively associated with desired number of children and negatively associated with age at first birth, although the latter association was only marginally significant in the multivariate analyses. Finally, path analysis showed that desired number of children and age at first birth completely mediated the relation between religiousness and reproductive success. The data confirmed the biologically adaptive function of religiousness in contemporary populations and found the mediating processes that facilitate fitness in religious individuals. Furthermore, the findings initiate a more complex view of religiousness in a life-history context which could be fruitful for future research: a proposal labelled as ‘ontogeny-dependent life-history theory of religiousness’.

scholarly journals Behavioral Paternity Predicts Genetic Paternity in Satin Bowerbirds (Ptilonorhynchus Violaceus), A Species With a Non-Resource-Based Mating System

The Auk ◽  
2007 ◽  
Vol 124 (3) ◽  
pp. 857-867 ◽  
Author(s):  
Sheila M. Reynolds ◽  
Katie Dryer ◽  
Jonathan Bollback ◽  
J. Albert C. Uy ◽  
Gail L. Patricelli ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Mating Behavior ◽  
Mating Success ◽  
Behavioral Observation ◽  
Male Mating ◽  
Male Mating Success ◽  
Video Cameras ◽  
Ptilonorhynchus Violaceus ◽  
Satin Bowerbird ◽  
Satin Bowerbirds

Abstract The potential for differences between genetic paternity and paternity inferred from behavioral observation has long been recognized. These differences are associated with the challenge for females of seeking both genetic and material benefits; this challenge is less severe in species with polygynous, non-resource-based mating systems (such as leks) than in those with resource-based systems. We present the first study of paternity patterns in a non-resource-based species that does not form true leks. We compared paternity inferred from observed mating behavior to genetically assigned paternity in the Satin Bowerbird (Ptilonorhynchus violaceus) using eight microsatellite markers. Mating behavior was observed and recorded via automated video-cameras positioned at all bowers (29–34 bowers each year) in the study site throughout each mating season. We obtained blood samples and identified mothers for 11 chicks in 9 nests. For all chicks, the most likely genetic father had been observed to mate with the mother in the year the chick was sampled. All most likely genetic fathers were assigned with high confidence and all were bower-holding males. These results demonstrate that genetic paternity can be inferred from observed mating behavior with reasonable confidence in Satin Bowerbirds. Observed male mating-success is therefore a reliable predictor of reproductive success, and this suggests that high skew in observed male mating-success translates directly to high skew in reproductive success. La Paternidad Comportamental Predice la Paternidad Genética en Ptilonorhynchus violaceus, una Especie con un Sistema de Apareamiento que No Está Basado en los Recursos

scholarly journals Age-based soldier polyethism: old termite soldiers take more risks than young soldiers

2018 ◽  
Vol 14 (3) ◽  
pp. 20180025 ◽  
Author(s):  
Saki Yanagihara ◽  
Wataru Suehiro ◽  
Yuki Mitaka ◽  
Kenji Matsuura
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Life Expectancy ◽  
Task Allocation ◽  
Life History Theory ◽  
Nest Defence ◽  
Front Line ◽  
Age Dependent ◽  
Predatory Ants ◽  
Termite Soldiers

Who should take on risky tasks in an age-heterogeneous society? Life-history theory predicts that, in social insects, riskier tasks should be undertaken by sterile individuals with a shorter life expectancy. The loss of individuals with shorter life expectancy is less costly for colony reproductive success than the loss of individuals with longer life expectancy. Termite colonies have a sterile soldier caste, specialized defenders engaged in the most risky tasks. Here we show that termite soldiers exhibit age-dependent polyethism, as old soldiers are engaged in front-line defence more than young soldiers. Our nest defence experiment showed that old soldiers went to the front line and blocked the nest opening against approaching predatory ants more often than young soldiers. We also found that young soldiers were more biased toward choosing central nest defence as royal guards than old soldiers. These results demonstrate that termite soldiers have age-based task allocation, by which ageing predisposes soldiers to switch to more dangerous tasks. This age-dependent soldier task allocation increases the life expectancy of soldiers, allowing them to promote their lifetime contribution to colony reproductive success.

scholarly journals Life-history traits and description of the new gonochoric amphimictic Mesobiotus joenssoni (Eutardigrada: Macrobiotidae) from the island of Elba, Italy

2019 ◽  
Author(s):  
Roberto Guidetti ◽  
Elisa Gneuß ◽  
Michele Cesari ◽  
Tiziana Altiero ◽  
Ralph O Schill
Keyword(s):  
Life History ◽  
Life History Theory ◽  
Life History Traits ◽  
Life Cycles ◽  
Life History Strategies ◽  
Egg Hatching ◽  
Body Segments ◽  
Hatching Time ◽  
Laboratory Cultures ◽  
The Mean

Abstract Comparative analyses of life-history theory studies are based on the characteristics of the life cycles of different species. For tardigrades, life-history traits are available only from laboratory cultures, most of which have involved parthenogenetic species. The discovery of a new gonochoristic bisexual Mesobiotus species in a moss collected on the island of Elba (Italy) provides us with the opportunity to describe Mesobiotus joenssoni sp. nov. and to collect data on the life-history traits of cultured specimens to increase our knowledge of the life-history strategies present in tardigrades. This new species is differentiated from all other species of the genus by the presence of granules (~1 µm in diameter) on the dorsal cuticle of the last two body segments, two large bulges (gibbosities) on the hindlegs and long, conical egg processes. The species exhibits sexual dimorphism in body length, with females being longer than males of the same age. The mean lifespan of specimens was 86 days, with a maximum of 150 days. The mean age at first oviposition was 19.8 days and the mean egg hatching time 15.4 days. The life-cycle traits correspond to those collected for the only other two macrobiotid species with gonochoric amphimictic reproduction examined so far.

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