scholarly journals Empirical evidence of plasticity in life-history characteristics across climatic and fish density gradients

2017 ◽  
Vol 74 (4) ◽  
pp. 464-474 ◽  
Author(s):  
Hillary G.M. Ward ◽  
John R. Post ◽  
Nigel P. Lester ◽  
Paul J. Askey ◽  
Theresa Godin
Keyword(s):  
Life History ◽  
Empirical Evidence ◽  
Growth Rates ◽  
Life History Theory ◽  
Resource Competition ◽  
Somatic Growth ◽  
Life History Strategies ◽  
Fish Density ◽  
Density Gradients ◽  
Life History Characteristics

Understanding how environmental productivity and resource competition influence somatic growth rates and plasticity in life-history traits is a critical component of population ecology. However, evolutionary effects often confound the relationship between plasticity in life-history characteristics and environmental productivity. We used a unique set of experimentally stocked populations of rainbow trout (Oncorhynchus mykiss) to empirically test predictions from life-history theory relating to patterns in immature growth rates, age- and size-at-maturity, and the energy allocated into reproduction across climatic and fish density gradients. Our results support theoretical predictions that plasticity in life-history characteristics is a function of environmental variables. In particular, we demonstrate that immature growth rates are best explained by climatic and density-dependent competition effects and that age-at-maturity and the energy allocated to reproduction depends on juvenile growth conditions. Empirical evidence of these relationships helps to improve our understanding of optimal life-history strategies of fish populations.

Temporal variation in the early life-history characteristics of the King George whiting (Sillaginodes punctata) from analysis of otolith microstructure

1996 ◽  
Vol 47 (6) ◽  
pp. 809 ◽  
Author(s):  
AJ Fowler ◽  
DA Short
Keyword(s):  
Life History ◽  
Growth Rates ◽  
Early Life ◽  
Somatic Growth ◽  
South Australia ◽  
Early Life History ◽  
Exponential Relationship ◽  
Life History Characteristics ◽  
Linear Relationships ◽  
Temperature Regimes

This study describes the duration of the settlement season, the somatic and otolith growth rates, and presettlement durations for Sillaginodes punctata at Barker Inlet, South Australia. The settlement season was from June to November, with settlement occurring in two phases over this period. Somatic growth rates ranged from <0.1 to 0.25 mm day-1 depending on age and time of year, making size (SL) a relatively poor indicator of age. Alternatively, otolith size (OL) was strongly related to age, but the linear relationships varied systematically among sampling occasions. Because of variation in somatic growth rates, the SL-OL relationships were relatively poor. The biological intercept method was used to back-calculate fish sizes from otolith increment widths for three samples of fish. These growth trajectories differed considerably, two being logistic in shape and the third being an exponential relationship. Presettlement durations increased from 80 to 130 days between June and September and were inversely related to growth rate. Settlement competence is related more to size than to age. The broad natural variation in early life-history characteristics is likely to relate to water temperature regimes along larval advection pathways through the long settlement season.

Sexual size dimorphism and life history traits in an island-mainland system: an overview of the lizard genus Microlophus

2021 ◽  
pp. 1-7
Author(s):  
Ken S. Toyama ◽  
Christopher K. Boccia
Keyword(s):  
Life History ◽  
South America ◽  
Life History Theory ◽  
Life History Traits ◽  
Sexual Size Dimorphism ◽  
Life History Strategies ◽  
Galápagos Islands ◽  
Size Dimorphism ◽  
Rensch's Rule ◽  
Comprehensive Compilation

Abstract Opposing life history strategies are a common result of the different ecological settings experienced by insular and continental species. Here we present a comprehensive compilation of data on sexual size dimorphism (SSD) and life history traits of Microlophus, a genus of lizards distributed in western South America and the Galápagos Islands, and test for differences between insular and continental species under life history theory expectations. Contrary to our predictions, we found no differences in SSD between localities or evidence that Microlophus follows Rensch’s rule. However, as expected, head dimensions and maturity sizes were significantly larger in insular species while continental species had larger clutches. Our results show that Microlophus exhibits some of the patterns expected from an island-mainland system, but unexplained patterns will only be resolved through future ecological, morphological and behavioural studies integrating both faunas.

Life History Strategies

2018 ◽  
pp. 95-126
Author(s):  
Marco Del Giudice
Keyword(s):  
Life History ◽  
Individual Differences ◽  
Life History Theory ◽  
Human Life ◽  
Life History Strategy ◽  
Current Theory ◽  
Life History Strategies ◽  
Extended Model ◽  
Life History Variation ◽  
Basic Model

The chapter introduces the basics of life history theory, the concept of life history strategy, and the fast–slow continuum of variation. After reviewing applications to animal behavior and physiology, the chapter reviews current theory and evidence on individual differences in humans as manifestations of alternative life history strategies. The chapter first presents a “basic model” of human life history–related traits, then advances an “extended model” that identifies multiple cognitive-behavioral profiles within fast and slow strategies. Specifically, it is proposed that slow strategies comprise prosocial/caregiving and skilled/provisioning profiles, whereas fast strategies comprise antisocial/exploitative and seductive/creative profiles. The chapter also reviews potential neurobiological markers of life history variation and considers key methodological issues in this area.

scholarly journals Cuckoos, cowbirds and hosts: adaptations, trade-offs and constraints

2006 ◽  
Vol 362 (1486) ◽  
pp. 1873-1886 ◽  
Author(s):  
Oliver Krüger
Keyword(s):  
Life History ◽  
Brood Parasitism ◽  
Reproductive Strategies ◽  
Life History Theory ◽  
Model Systems ◽  
Life History Strategies ◽  
Host System ◽  
Brood Parasites ◽  
Trade Offs ◽  
Evolution Of Life

The interactions between brood parasitic birds and their host species provide one of the best model systems for coevolution. Despite being intensively studied, the parasite–host system provides ample opportunities to test new predictions from both coevolutionary theory as well as life-history theory in general. I identify four main areas that might be especially fruitful: cuckoo female gentes as alternative reproductive strategies, non-random and nonlinear risks of brood parasitism for host individuals, host parental quality and targeted brood parasitism, and differences and similarities between predation risk and parasitism risk. Rather than being a rare and intriguing system to study coevolutionary processes, I believe that avian brood parasites and their hosts are much more important as extreme cases in the evolution of life-history strategies. They provide unique examples of trade-offs and situations where constraints are either completely removed or particularly severe.

scholarly journals The effects of age at menarche and first sexual intercourse on reproductive and behavioural outcomes: a Mendelian randomization study

2018 ◽  
Author(s):  
Rebecca B Lawn ◽  
Hannah M Sallis ◽  
Robyn E Wootton ◽  
Amy E Taylor ◽  
Perline Demange ◽  
...  
Keyword(s):  
Life History ◽  
Sexual Intercourse ◽  
Life History Theory ◽  
Mendelian Randomization ◽  
Causal Effect ◽  
Life History Strategies ◽  
Age At Menarche ◽  
Age At First Birth ◽  
Risky Behaviour ◽  
First Sexual Intercourse

SummaryThere is substantial variation in the timing of significant reproductive life events such as menarche and first sexual intercourse. Life history theory explains this variation as an adaptive response to the developmental environment. In environments characterized by harsh conditions, adopting a fast life history strategy may increase fitness. In line with this, there is evidence demonstrating that greater childhood adversity is associated with earlier age at menarche. Here we applied Mendelian randomization (MR) methods to investigate whether there is a causal effect of variation in age at menarche and age at first sexual intercourse on outcomes related to reproduction, education and risky behaviour in UK Biobank (N = 114883–181,255). Our results suggest that earlier age at menarche affects some traits that characterize life history strategies including earlier age at first and last birth, decreased educational attainment, and decreased age at leaving education (for example, we found evidence for a 0.26 year decrease in age at first birth per year decrease in age at menarche, 95% confidence interval: −0.34 to −0.17; p < 0.0001). We find no clear evidence of effects of age at menarche on other outcomes, such as risk taking behaviour. Age at first sexual intercourse was also related to many life history outcomes, although there was evidence of horizontal pleiotropy which violates an assumption of MR and results should be treated with caution. Taken together, these results highlight how MR can be applied to test predictions of life history theory and to better understand determinants of health and social behaviour.

scholarly journals Diagnosing the dangerous demography of manta rays using life history theory

2013 ◽  
Author(s):  
Nicholas K Dulvy ◽  
Sebastián A. Pardo ◽  
Colin A. Simpfendorfer ◽  
John K. Carlson
Keyword(s):  
Life History ◽  
Life History Theory ◽  
Extinction Risk ◽  
Somatic Growth ◽  
Intrinsic Rate ◽  
Population Increase ◽  
Population Declines ◽  
Demographic Information ◽  
Age At Maturity ◽  
Manta Ray

The directed harvest and global trade in the gill plates of mantas, and other mobulid rays, has led to increased fishing pressure and steep population declines in some locations. The slow life history, particularly of the manta rays, is cited as a key reason why such species have little capacity to withstand directed fisheries. Here, we place their life history and demography in the context of other sharks and rays. Despite the limited availability of data, we use life history theory and comparative analysis to develop plausible ranges of somatic growth rate, annual pup production and age at maturity to estimate risk of extinction (maximum intrinsic rate of population increase rmax) using a variant of the classic Euler-Lotka model. Manta ray rmax is most sensitive to the length of the reproductive cycle, and the median rmax of 0.11 year-1(CI: 0.089-0.137) is one of the lowest known of the 106 sharks and rays for which we have comparable demographic information. In common with other unprotected, unmanaged, high-value large-bodied species with low or very low productivity, manta rays are unlikely to sustain unmonitored, unregulated exploitation and may face increasing local and regional extinction risk.

Trait-Based Approach to Fish Ecology

2019 ◽  
pp. 150-160
Author(s):  
Ken H. Andersen
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Life History Strategy ◽  
Somatic Growth ◽  
Population Level ◽  
Historical Background ◽  
Life History Strategies ◽  
Asymptotic Size ◽  
Current State ◽  
Investment In Reproduction

This chapter proposes a shortlist of fish “master” traits and connects these traits to classic life-history strategy thinking. First, it sets the historical background for the current state-of-the-art thinking about fish life history strategies. From there, the chapter explains that the main axes of variation between fish species can be captured by three traits: the asymptotic size; the growth rate coefficient; and the adult–offspring mass ratio strategy. Together, these three traits determine the central demographic parameters: somatic growth rate, investment in reproduction, age at maturation, survival to maturation, mortality, and so on, and from there follows population-level quantities like population growth rate, population structure, fitness, and selection responses. The chapter concludes with a reflection on the trait-based approach and compares it to other methods of assessment.

scholarly journals Differential reproductive responses to stress reveal the role of life-history strategies within a species

2013 ◽  
Vol 280 (1771) ◽  
pp. 20132090 ◽  
Author(s):  
J. Schultner ◽  
A. S. Kitaysky ◽  
G. W. Gabrielsen ◽  
S. A. Hatch ◽  
C. Bech
Keyword(s):  
Life History ◽  
Life History Theory ◽  
Life History Strategies ◽  
Short Term ◽  
Food Shortages ◽  
Investment In Reproduction ◽  
Response To Stress ◽  
Environmental Events ◽  
Two Populations

Life-history strategies describe that ‘slow’- in contrast to ‘fast’-living species allocate resources cautiously towards reproduction to enhance survival. Recent evidence suggests that variation in strategies exists not only among species but also among populations of the same species. Here, we examined the effect of experimentally induced stress on resource allocation of breeding seabirds in two populations with contrasting life-history strategies: slow-living Pacific and fast-living Atlantic black-legged kittiwakes. We tested the hypothesis that reproductive responses in kittiwakes under stress reflect their life-history strategies. We predicted that in response to stress, Pacific kittiwakes reduce investment in reproduction compared with Atlantic kittiwakes. We exposed chick-rearing kittiwakes to a short-term (3-day) period of increased exogenous corticosterone (CORT), a hormone that is released during food shortages. We examined changes in baseline CORT levels, parental care and effects on offspring. We found that kittiwakes from the two populations invested differently in offspring when facing stress. In response to elevated CORT, Pacific kittiwakes reduced nest attendance and deserted offspring more readily than Atlantic kittiwakes. We observed lower chick growth, a higher stress response in offspring and lower reproductive success in response to CORT implantation in Pacific kittiwakes, whereas the opposite occurred in the Atlantic. Our findings support the hypothesis that life-history strategies predict short-term responses of individuals to stress within a species. We conclude that behaviour and physiology under stress are consistent with trade-off priorities as predicted by life-history theory. We encourage future studies to consider the pivotal role of life-history strategies when interpreting inter-population differences of animal responses to stressful environmental events.

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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