scholarly journals Life history of a short-lived squid (Sepioteuthis australis): resource allocation as a function of size, growth, maturation, and hatching season

2006 ◽  
Vol 63 (6) ◽  
pp. 995-1004 ◽  
Author(s):  
Gretta T. Pecl ◽  
Natalie A. Moltschaniwskyj
Keyword(s):  
Life History ◽  
Body Shape ◽  
Adult Life ◽  
Reproductive Investment ◽  
Reproductive Condition ◽  
Trade Offs ◽  
Size Growth ◽  
History Of ◽  
Slow Growing ◽  
Alternation Of Generations

Abstract Many cephalopods continue growing while laying multiple egg batches over the adult life, with repro-somatic allocation continuing beyond attainment of reproductive maturity. Many species show extreme individual variation in reproductive investment. Factors driving this variation in adult Sepioteuthis australis were evaluated by examining allocation of energy to somatic and reproductive growth as a function of body shape, growth rate, maturation, and hatching season. Hatching season influence was sex-specific; males hatched in warmer months had greater reproductive investment, faster growth, and better somatic and reproductive condition, whereas females hatched in spring and summer had less reproductive investment. Seasonal impacts on life history resulted in an “alternation of generations”, with slow-growing squid in poor condition and with high levels of reproductive investment producing a generation with completely different life-history characteristics. This suggests that abiotic and biotic conditions that change seasonally could play a large role in determining energy allocated to reproduction. However, this was not driving trade-offs between size and number of offspring. Life-history trade-offs should be detectable as negative correlations between relevant traits. However, in Sepioteuthis australis there was little evidence of trade-offs between reproduction and growth or condition of individuals, suggesting a “live for today” lifestyle.

scholarly journals On Apogamy and the development of Sporangia upon fern prothalli

1898 ◽  
Vol 63 (389-400) ◽  
pp. 56-61
Keyword(s):  
Life History ◽  
Point Of View ◽  
The Other ◽  
Normal Life ◽  
Other Hand ◽  
General Importance ◽  
Two Generations ◽  
History Of ◽  
Alternation Of Generations

The two most important deviations from the normal life-history of ferns, apogamy and apospory, are of interest in themselves, but acquire a more general importance from the possibility that their study may throw light on the nature of alternation of generations in archegoniate plants. They have been considered from this point of view Pringsheim, and by those who, following him, regard the two generations as homologous with one another in the sense that the sporophyte arose by the gradual modification of individuals originally resemblin the sexual plant. Celakovsky and Bower, on the other hand, maintaint the view tha t the sporophyte, as an interpolated stage in the life-history arising by elaboration of the zygote, a few thallophytes.

scholarly journals Enzymatic antioxidants but not baseline glucocorticoids mediate the reproduction–survival trade-off in a wild bird

2018 ◽  
Vol 285 (1892) ◽  
pp. 20182141 ◽  
Author(s):  
Stefania Casagrande ◽  
Michaela Hau
Keyword(s):  
Life History ◽  
Body Condition ◽  
Redox State ◽  
Reproductive Investment ◽  
Redox System ◽  
Reactive Oxygen Metabolites ◽  
Enzymatic Antioxidants ◽  
Trade Off ◽  
Trade Offs ◽  
Nest Provisioning

The trade-off between reproductive investment and survival is central to life-history theory, but the relative importance and the complex interactions among the physiological mechanisms mediating it are still debated. Here we experimentally tested whether baseline glucocorticoid hormones, the redox system or their interaction mediate reproductive investment–survival trade-offs in wild great tits ( Parus major ). We increased the workload of parental males by clipping three feathers on each wing, and 5 days later determined effects on baseline corticosterone concentrations (Cort), redox state (reactive oxygen metabolites, protein carbonyls, glutathione peroxidase [GPx], total non-enzymatic antioxidants), body mass, body condition, reproductive success and survival. Feather-clipping did not affect fledgling numbers, chick body condition, nest provisioning rates or survival compared with controls. However, feather-clipped males lost mass and increased both Cort and GPx concentrations. Within feather-clipped individuals, GPx increases were positively associated with reproductive investment (i.e. male nest provisioning). Furthermore, within all individuals, males that increased GPx suffered reduced survival rates. Baseline Cort increases were related to mass loss but not to redox state, nest provisioning or male survival. Our findings provide experimental evidence that changes in the redox system are associated with the trade-off between reproductive investment and survival, while baseline Cort may support this trade-off indirectly through a link with body condition. These results also emphasize that plastic changes in individuals, rather than static levels of physiological signals, may mediate life-history trade-offs.

scholarly journals The influence of juvenile and adult environments on life-history trajectories

2005 ◽  
Vol 273 (1587) ◽  
pp. 741-750 ◽  
Author(s):  
Barbara Taborsky
Keyword(s):  
Life History ◽  
Life Histories ◽  
Adult Life ◽  
Growth Conditions ◽  
Offspring Size ◽  
Juvenile Growth ◽  
Life History Variation ◽  
Major Life ◽  
Adult Growth ◽  
Trade Offs

There is increasing evidence that the environment experienced early in life can strongly influence adult life histories. It is largely unknown, however, how past and present conditions influence suites of life-history traits regarding major life-history trade-offs. Especially in animals with indeterminate growth, we may expect that environmental conditions of juveniles and adults independently or interactively influence the life-history trade-off between growth and reproduction after maturation. Juvenile growth conditions may initiate a feedback loop determining adult allocation patterns, triggered by size-dependent mortality risk. I tested this possibility in a long-term growth experiment with mouthbrooding cichlids. Females were raised either on a high-food or low-food diet. After maturation half of them were switched to the opposite treatment, while the other half remained unchanged. Adult growth was determined by current resource availability, but key reproductive traits like reproductive rate and offspring size were only influenced by juvenile growth conditions, irrespective of the ration received as adults. Moreover, the allocation of resources to growth versus reproduction and to offspring number versus size were shaped by juvenile rather than adult ecology. These results indicate that early individual history must be considered when analysing causes of life-history variation in natural populations.

Explanations for attractiveness-related positive biases in an evolutionary perspective of life history theory

2017 ◽  
Vol 40 ◽  
Author(s):  
Bin-Bin Chen
Keyword(s):  
Life History ◽  
Life History Theory ◽  
Infants And Children ◽  
Evolutionary Explanation ◽  
Evolutionary Perspective ◽  
Trade Offs ◽  
History Of

AbstractThe mating-related evolutionary explanation that Maestripieri et al. offer does not apply to (1) infants' positive biases toward attractive individuals and (2) adults' positive biases toward attractive infants and children. They are best understood when integrated into an evolutionary life history framework. I argue that the life history of positive biases toward attractive individuals is driven by fundamental trade-offs made throughout development.

Effect of body size, age and timing of breeding on clutch and egg size of female Eastern Gray Treefrogs, Hyla versicolor

2021 ◽  
pp. 1-11
Author(s):  
Gerlinde Höbel ◽  
Robb Kolodziej ◽  
Dustin Nelson ◽  
Christopher White
Keyword(s):  
Life History ◽  
Egg Size ◽  
Life History Theory ◽  
Reproductive Investment ◽  
Ecological Factors ◽  
Hyla Versicolor ◽  
Growth And Survival ◽  
Factors Affecting ◽  
Trade Offs ◽  
Gray Treefrogs

Abstract Information on how organisms allocate resources to reproduction is critical for understanding population dynamics. We collected clutch size (fecundity) and egg size data of female Eastern Gray Treefrogs, Hyla versicolor, and examined whether observed patterns of resource allocation are best explained by expectations arising from life history theory or by expected survival and growth benefits of breeding earlier. Female Hyla versicolor showed high between-individual variation in clutch and egg size. We did not observe maternal allocation trade-offs (size vs number; growth vs reproduction) predicted from life history theory, which we attribute to the large between-female variation in resource availability, and the low survival and post-maturity growth rate observed in the study population. Rather, clutches are larger at the beginning of the breeding season, and this variation in reproductive investment aligns with seasonal variation in ecological factors affecting offspring growth and survival.

XXI.—The Life-history and Development of Agriolimax agrestis L., the Gray Field Slug.

1939 ◽  
Vol 59 (3) ◽  
pp. 563-597 ◽  
Author(s):  
Robert Carrick
Keyword(s):  
Life History ◽  
Life Histories ◽  
Adult Life ◽  
Single Species ◽  
Functional Changes ◽  
Breeding Habit ◽  
Early Stages ◽  
History Of ◽  
Highly Evolved

Among Gasteropod Molluscs the life-histories and development of the most highly evolved members, the terrestrial Pulmonates, have been less intensively studied than those of more primitive aquatic forms. This has been due in part to the technical difficulties involved in the permanent preparation of material for study, and in part to the fact that the investigator seeking for primitive features of phyletic interest is more likely to find these among more generalised species of Gasteropods than among those which are obviously adapted, both during the early stages of their development and in adult life, to a habitat far removed from the ancestral one.It is the purpose of this paper to present data bearing upon the life-history of a single species of land Pulmonate, Agriolimax agrestis L., to enlarge upon certain aspects of the embryology of this species, and to demonstrate the structural and functional changes of the larva which have accompanied the transition from an aquatic to a terrestrial breeding habit.

Adult lifetime reproductive value in fish depends on size and fecundity type

2016 ◽  
Vol 73 (9) ◽  
pp. 1405-1412 ◽  
Author(s):  
Stavroula Tsoukali ◽  
Karin H. Olsson ◽  
André W. Visser ◽  
Brian R. MacKenzie
Keyword(s):  
Life History ◽  
Early Life ◽  
Life History Traits ◽  
Life Stage ◽  
Adult Life ◽  
Early Life Stage ◽  
Reproductive Value ◽  
Trade Offs ◽  
Direct Proportionality ◽  
Proportionality Relationship

In a stable population, the adult lifetime reproductive value must be balanced against early life survival. Although delaying maturity may increase fecundity, it also reduces survival. Larger size at maturity therefore not only allows for higher fecundity, but requires it. Using simple arguments from life history, we derive a direct proportionality relationship between the adult lifetime reproductive value and weight at maturation and find that this relationship is consistent with empirical evidence from 28 stocks and species of bony fish from temperate–boreal environments. However, the expected proportionality falls off if mortality increases to include fishing. Furthermore, we find that the fecundity type (determinate or indeterminate) affects the predicted adult reproductive value, which is significantly (10-fold) higher for an indeterminate spawner than for a determinate spawner of the same weight. These differences may relate to trade-offs in the adult life history traits and (or) to seasonality in the spawning environment, with subsequent consequences for early life stage survivorship.

The Duration of Lactation in Antechinus-Stuartii (Marsupialia, Dasyuridae)

1992 ◽  
Vol 40 (2) ◽  
pp. 195 ◽  
Author(s):  
A Cockburn
Keyword(s):  
Life History ◽  
Reproductive Investment ◽  
Breeding Density ◽  
Free Living ◽  
Weaning Weight ◽  
Trade Offs ◽  
Antechinus Stuartii ◽  
Recent Debate ◽  
The Difference

Free-living Antechinus stuartii at the Monga State Forest showed almost no variation in date of birth, yet weaning took place over a period of three weeks. Males were weaned slightly earlier and at greater weights than females. When daughters were considered, weaning was delayed in years when breeding density was high, and females with ten teats weaned their young later and at slightly lower weights than females with eight teats. The difference between the two teat phenotypes was not simply associated with increased reproductive investment, as successful eight-teated mothers weaned their young earlier than less successful mothers, and there was no relation between weaning success and date of weaning for ten-teated mothers. Age of mother did not influence weaning weight or date, and mothers tended to wean at the same time in each year of their life. These patterns are discussed in relation to recent debate on the detection of life-history trade-offs in free-living populations.

The cost of trying: weak interspecific correlations among life-history components in male ungulates

2012 ◽  
Vol 90 (9) ◽  
pp. 1072-1085 ◽  
Author(s):  
Marco Festa-Bianchet
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Life History Traits ◽  
Male Reproductive Success ◽  
Main Determinant ◽  
Young Males ◽  
Asymptotic Size ◽  
Trade Offs ◽  
The Cost ◽  
Slow Growing

Life-history trade-offs are well known in female mammals, but have seldom been quantified for males in polygynous species. I compared age-specific mass, weapon size, survival, and reproductive success of males in eight species of ungulates, and found weak interspecific correlations among life-history traits. Young males tended to have higher reproductive success in rapidly-growing than in slow-growing species, and in species where horns or antlers reached near-asymptotic size over the first few years of life. There was no clear interspecific trade-off between early reproduction and early survival. Reproductive senescence was evident in most species. Generation length, calculated as the mean age of fathers, was negatively correlated with the reproductive success of young males and positively with life expectancy of 3-year-olds, but not with early mortality. The main determinant of male reproductive success in polygynous ungulates is the ability to prevail against competing males. Consequently, the number and age structure of competitors should strongly affect an individual’s ability to reproduce, making classic trade-offs among life-history traits very context-dependent. Most fitness costs of reproduction in male ungulates likely arise from energy expenditure and injuries sustained while attempting to mate. Individual costs may be weakly correlated with fitness returns.

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