scholarly journals Senescent birds redouble reproductive effort when ill: confirmation of the terminal investment hypothesis

2006 ◽  
Vol 273 (1593) ◽  
pp. 1443-1448 ◽  
Author(s):  
Alberto Velando ◽  
Hugh Drummond ◽  
Roxana Torres
Keyword(s):  
Reproductive Success ◽  
Reproductive Effort ◽  
Initial Increase ◽  
Male Reproductive Success ◽  
Age Classes ◽  
Theoretical Idea ◽  
Sula Nebouxii ◽  
Terminal Investment ◽  
Survival And Reproduction ◽  
Investment Hypothesis

This study reports an experimental confirmation of the terminal investment hypothesis, a longstanding theoretical idea that animals should increase their reproductive effort as they age and their prospects for survival and reproduction decline. Previous correlational and experimental attempts to test this hypothesis have yielded contradictory results. In the blue-footed booby, Sula nebouxii , a long-lived bird, after initial increase, male reproductive success declines progressively with age. Before laying, males of two age classes were challenged with lipopolysaccharide to elicit an immune response, which induced symptoms of declining survival prospects. Reproductive success of immune-challenged mature males fell, while that of immune-challenged old males showed a 98% increase. These results demonstrate that senescent males with poor reproductive prospects increase their effort when those prospects are threatened, whereas younger males with good reproductive prospects do not.

Older conservatives: reproduction in female Alpine chamois (Rupicapra rupicapra) is increasingly risk-averse with age

2016 ◽  
Vol 94 (5) ◽  
pp. 311-321 ◽  
Author(s):  
A. Morin ◽  
M. Rughetti ◽  
S. Rioux-Paquette ◽  
M. Festa-Bianchet
Keyword(s):  
Reproductive Success ◽  
Reproductive Effort ◽  
Risk Averse ◽  
Costs Of Reproduction ◽  
Rupicapra Rupicapra ◽  
Terminal Investment ◽  
Age Dependent ◽  
Alpine Chamois ◽  
Old Females ◽  
Investment Hypothesis

In long-lived mammals, costs of reproduction may vary with age. The terminal investment hypothesis predicts greater reproductive effort as females approach the end of their life expectancy. We monitored 97 individually marked female Alpine chamois (Rupicapra rupicapra (L., 1758)) between 2007 and 2013 to determine how age-specific reproduction affected body mass and subsequent reproductive success. We captured and weighed females between April and August and monitored reproductive success from April to October through mother–kid associations. Reproductive success was strongly age-dependent and peaked at 70% for prime-aged females (4–7 years). Reproductive senescence began at 8 years, earlier than reported by other studies of ungulates. There was no clear evidence of reproductive costs in any age class. Reproductive success was very heterogeneous for old females, suggesting variability in the onset of senescence. Old females were less likely to reproduce in poor years despite being heavier than prime-aged females, suggesting reproductive restraint in late life rather than terminal investment. Female mass remained stable from May to August with no effect of lactation. Our results suggest that chamois reproductive strategy becomes increasingly conservative with age, resulting in no detectable costs of reproduction.

scholarly journals Amphibians with infectious disease increase their reproductive effort: evidence for the terminal investment hypothesis

Open Biology ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 150251 ◽  
Author(s):  
Laura A. Brannelly ◽  
Rebecca Webb ◽  
Lee F. Skerratt ◽  
Lee Berger
Keyword(s):  
Disease Resistance ◽  
Reproductive Effort ◽  
Batrachochytrium Dendrobatidis ◽  
Population Level ◽  
Life History Trait ◽  
Terminal Investment ◽  
Frog Species ◽  
Selection For ◽  
Declining Species ◽  
Investment Hypothesis

Mounting an immune response to fight disease is costly for an organism and can reduce investment in another life-history trait, such as reproduction. The terminal investment hypothesis predicts that an organism will increase reproductive effort when threatened by disease. The reproductive fitness of amphibians infected with the deadly fungal pathogen Batrachochytrium dendrobatidis ( Bd ) is largely unknown. In this study, we explored gametogenesis in two endangered and susceptible frog species, Pseudophryne corroboree and Litoria verreauxii alpina. Gametogenesis, both oogenesis and spermatogenesis, increased when animals were experimentally infected with Bd . In P. corroboree , infected males have thicker germinal epithelium, and a larger proportion of spermatocytes. In L. v. alpina , infected males had more spermatic cell bundles in total, and a larger proportion of spermatozoa bundles. In female L. v. alpina , ovaries and oviducts were larger in infected animals, and there were more cells present within the ovaries. Terminal investment has consequences for the evolution of disease resistance in declining species. If infected animals are increasing reproductive efforts and producing more offspring before succumbing to disease, it is possible that population-level selection for disease resistance will be minimized.

Male lake sturgeon (Acipenser fulvescens) migratory and spawning behaviors are associated with sperm quality and reproductive success

2020 ◽  
Vol 77 (12) ◽  
pp. 1943-1959
Author(s):  
Douglas L. Larson ◽  
Jacob G. Kimmel ◽  
Joseph J. Riedy ◽  
Jonathan Hegna ◽  
Edward A. Baker ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Reproductive Effort ◽  
Sperm Quality ◽  
Lake Sturgeon ◽  
Operational Sex Ratio ◽  
Computer Assisted ◽  
Acipenser Fulvescens ◽  
Male Reproductive Success ◽  
Upstream Migration ◽  
Sperm Depletion

Intra-annual reproductive investments may not be predictive of male reproductive success because of the effects of intra- and intersexual interactions on sperm depletion. For long-lived iteroparous fish species such as lake sturgeon (Acipenser fulvescens), reproductive effort may affect lifetime reproductive success. Radio frequency identification antennas were placed at the mouth of the Upper Black River, Michigan, and downstream of spawning locations to quantify male migratory and mating behaviors, including upstream migration time (UT), river residence time (RT), number of intra-annual spawning migrations (IM), interannual spawning interval, and operational sex ratio during 2017–2018. Computer assisted sperm analysis was used to quantify sperm quality. RT had a strong negative influence on sperm concentration and with measures of sperm quality. RT and the number of females encountered were positively associated with male reproductive success (number of offspring sired) across years. RT, IM, and UT were negatively associated with sperm quality, indicating sperm depletion is a reliable measure of sexual activity. Results demonstrate trade-offs between benefits and costs associated with current reproductive effort on future reproduction.

scholarly journals Linking Male Reproductive Success to Effort Within and Among Nests in a Co-Breeding Stream Fish

2021 ◽  
Author(s):  
Seoghyun Kim ◽  
Mevin B. Hooten ◽  
Tanya L. Darden ◽  
Yoichiro Kanno
Keyword(s):  
South Carolina ◽  
Reproductive Success ◽  
Breeding Season ◽  
Reproductive Effort ◽  
Nest Size ◽  
Male Reproductive Success ◽  
Small Stream ◽  
Bayesian Hierarchical ◽  
Cooperative Behaviors ◽  
Nocomis Leptocephalus

Abstract Nest construction is an energetically costly behavior displayed by males in many taxa. In some species, males construct nests and co-breed with other males and they may construct multiple nests in a breeding season. However, little is understood about how allocation of effort within and among nests affects male reproductive success. We characterized reproductive effort of male bluehead chub (Nocomis leptocephalus) on nests in an entire breeding season using PIT antennas deployed around nests and linked effort within and among nests to reproductive success, measured by number of offspring assigned genetically to each male, in a small stream in South Carolina, USA. We monitored time spent by a total of 34 males on each of 18 nests during the spawning season in 2017. A Bayesian hierarchical analysis showed that larger males spent more time constructing and maintaining a given nest, and consequently were more reproductively successful than smaller males on the same nest. Combined with aggressive behavior displayed by larger males toward smaller males, this finding suggested that reproductive effort including agonistic interactions within nests was a determinant of reproductive success. In contrast, more males together constructed larger nests, which led to higher reproductive success of members that constructed those nests. Number of nests that male constructed, a measure of effort across nests, was not a predictor of reproductive success, indicating that reproductive success varied among nests due to nest size. Our study showed that male reproductive success was determined by both aggressive and cooperative behaviors in a co-breeding species.

scholarly journals Ant queens increase their reproductive efforts after pathogen infection

2017 ◽  
Vol 4 (7) ◽  
pp. 170547 ◽  
Author(s):  
Julia Giehr ◽  
Anna V. Grasse ◽  
Sylvia Cremer ◽  
Jürgen Heinze ◽  
Alexandra Schrempf
Keyword(s):  
Social Insect ◽  
Reproductive Effort ◽  
Reproductive Rate ◽  
Egg Laying ◽  
Reproductive Value ◽  
Reproductive Senescence ◽  
Terminal Investment ◽  
Investment In Reproduction ◽  
First Time ◽  
Investment Hypothesis

Infections with potentially lethal pathogens may negatively affect an individual's lifespan and decrease its reproductive value. The terminal investment hypothesis predicts that individuals faced with a reduced survival should invest more into reproduction instead of maintenance and growth. Several studies suggest that individuals are indeed able to estimate their body condition and to increase their reproductive effort with approaching death, while other studies gave ambiguous results. We investigate whether queens of a perennial social insect (ant) are able to boost their reproduction following infection with an obligate killing pathogen. Social insect queens are special with regard to reproduction and aging, as they outlive conspecific non-reproductive workers. Moreover, in the ant Cardiocondyla obscurior , fecundity increases with queen age. However, it remained unclear whether this reflects negative reproductive senescence or terminal investment in response to approaching death. Here, we test whether queens of C. obscurior react to infection with the entomopathogenic fungus Metarhizium brunneum by an increased egg-laying rate. We show that a fungal infection triggers a reinforced investment in reproduction in queens. This adjustment of the reproductive rate by ant queens is consistent with predictions of the terminal investment hypothesis and is reported for the first time in a social insect.

scholarly journals Postweaning maternal care increases male chimpanzee reproductive success

2020 ◽  
Vol 6 (38) ◽  
pp. eaaz5746
Author(s):  
Catherine Crockford ◽  
Liran Samuni ◽  
Linda Vigilant ◽  
Roman M. Wittig
Keyword(s):  
Reproductive Success ◽  
Parental Investment ◽  
Maternal Care ◽  
Parental Loss ◽  
Male Reproductive Success ◽  
Complex Societies ◽  
Successful Reproduction ◽  
Using Data

Humans are unusual among animals for continuing to provision and care for their offspring until adulthood. This “prolonged dependency” is considered key for the evolution of other notable human traits, such as large brains, complex societies, and extended postreproductive lifespans. Prolonged dependency must therefore have evolved under conditions in which reproductive success is gained with parental investment and diminished with early parental loss. We tested this idea using data from wild chimpanzees, which have similarly extended immature years as humans and prolonged mother-offspring associations. Males who lost their mothers after weaning but before maturity began reproducing later and had lower average reproductive success. Thus, persistent mother-immature son associations seem vital for enhancing male reproductive success, although mothers barely provision sons after weaning. We posit that these associations lead to social gains, crucial for successful reproduction in complex social societies, and offer insights into the evolution of prolonged dependency.

POLYGYNY, REPRODUCTIVE SUCCESS AND CHILD HEALTH IN RURAL ETHIOPIA: WHY MARRY A MARRIED MAN?

2006 ◽  
Vol 39 (2) ◽  
pp. 287-300 ◽  
Author(s):  
MHAIRI A. GIBSON ◽  
RUTH MACE
Keyword(s):  
Reproductive Success ◽  
Male Reproductive Success ◽  
Family Status ◽  
Rural Ethiopia ◽  
Younger Age ◽  
Married Individuals ◽  
Males And Females ◽  
Child Nutritional Status ◽  
And Child Health ◽  
Better Than

Summary.This study examines the reproductive success of men and women in rural Ethiopia as a function of their marital status, specifically by comparing polygamously and monogamously married individuals. In line with predictions from evolutionary theory, polygamy is beneficial to male reproductive success (i.e. producing larger numbers of surviving offspring). The success of polygamously married females depends on wife rank: the first wives of polygamous husbands do better than monogamously married women and much better than second or third wives. These effects are mirrored in child nutritional status: the children of second and third wives have lower weight for height. Due to potential, largely unmeasurable differences in marriageability (quality) between individuals, it was not possible to support a model of either resource-holding polygyny combined with female choice or female coercion into unwanted marriages. First wives of polygamously married men marry at a younger age and attract a higher brideprice, suggesting that both the males and females in the marriage are likely to be of higher quality (due to wealth, family status or some other factor such as beauty). Unions that end up monogamous are likely to be between slightly lower quality individuals; and second and third wives, who marry at the oldest ages and attract the lowest brideprice, may be ‘making the best of a bad job’. The relatively long gap between first and second marriages may mean that first wives of highly marriageable males can enjoy considerable reproductive success before their husbands marry again.

Carotenoid-based plumage colouration in red bishops (Euplectes orix) — signalling presence rather than quality?

Behaviour ◽  
2011 ◽  
Vol 148 (11-13) ◽  
pp. 1372-1392 ◽  
Author(s):  
Alice U. Edler ◽  
Thomas W.P. Friedl
Keyword(s):  
Reproductive Success ◽  
Parasite Load ◽  
Blood Parasite ◽  
Male Reproductive Success ◽  
Sexually Dimorphic ◽  
Male Quality ◽  
Plumage Colouration ◽  
Selection For ◽  
Breeding Plumage

AbstractThe role of bright plumage colouration for female choice has been the focus of research in sexual selection for many years, with several studies showing that females prefer the most elaborately ornamented males, which are often also the highest quality individuals. Here, we analysed the associations between reproductive performance and plumage, body condition and blood parasite load in the red bishop (Euplectes orix), a sexually dimorphic and polygynous weaverbird species, where males in a carotenoid-based orange-to-red breeding plumage defend territories and build many nests to which they try to attract females. Male reproductive success in terms of number of nests accepted was mainly determined by the number of nests built, but was also positively related to blood parasite load, while we found no influence of plumage characteristics. Together with previously obtained data, our results indicate that plumage characteristics in the red bishop do not affect male reproductive success and are generally not suitable to reliably indicate male quality. We suggest that the primary function of the brilliant orange-scarlet breeding plumage might be presence signalling in terms of increasing conspicuousness of breeding males to females searching for mates.

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