Adjustment of Parental Investment with Mate Quality by Male Yellow-Headed Blackbirds (Xanthocephalus xanthocephalus)

The Auk ◽  
1988 ◽  
Vol 105 (4) ◽  
pp. 672-680 ◽  
Author(s):  
David F. Gori
Keyword(s):  
Parental Investment ◽  
Feeding Rate ◽  
Male Reproductive Success ◽  
Paternal Investment ◽  
Parental Competence ◽  
Mate Quality ◽  
Male Preference ◽  
Offspring Number ◽  
Xanthocephalus Xanthocephalus ◽  
Fledging Mass

Abstract By removing young from the nests of competent females, I tested whether male Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) could assess the parental competence of mates and adjust their parental investment accordingly. The purpose of this experimental reduction was to equalize the number of young in nests of parentally competent and incompetent females in order to control for the effect of offspring number on parental investment by males. Males had a greater probability of feeding at nests of competent-reduced females and they fed at a higher rate than they did at nests of incompetent females. The latter broods were fed only when nests belonging to competent females were unavailable. Males adjust their parental investment with mate quality independent of the number of young in nests. To explain this preference, I constructed functions to relate the amount of paternal investment (i.e. male feeding rate) to the number of young fledged from nests and the fledging mass of young. The latter are two components of male reproductive success and, therefore, estimates of the "return" on a male's parental investment. Male feeding had no effect on the number of young fledged from starvation-reduced or experimental nests. However, the fledging mass of young increased more when males helped competent females than when incompetent females were helped. Thus male preference for helping competent females may result because the return per unit of their investment is greater at these nests.

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.

scholarly journals Differential Allocation Revisited: When Should Mate Quality Affect Parental Investment?

2017 ◽  
Vol 190 (4) ◽  
pp. 534-546 ◽  
Author(s):  
Thomas R. Haaland ◽  
Jonathan Wright ◽  
Bram Kuijper ◽  
Irja I. Ratikainen
Keyword(s):  
Parental Investment ◽  
Differential Allocation ◽  
Mate Quality

scholarly journals Sex-biased immunity is driven by relative differences in reproductive investment

2014 ◽  
Vol 281 (1790) ◽  
pp. 20140333 ◽  
Author(s):  
Crystal M. Vincent ◽  
Darryl T. Gwynne
Keyword(s):  
Immune Response ◽  
Sex Differences ◽  
Immune System ◽  
Sexual Dimorphism ◽  
Parental Investment ◽  
Sex Role ◽  
Reproductive Investment ◽  
Paternal Investment ◽  
Sexual Competition ◽  
Relative Differences

Sex differences in immunity are often observed, with males generally having a weaker immune system than females. However, recent data in a sex-role-reversed species in which females compete to mate with males suggest that sexually competitive females have a weaker immune response. These findings support the hypothesis that sexual dimorphism in immunity has evolved in response to sex-specific fitness returns of investment in traits such as parental investment and longevity, but the scarcity of data in sex-reversed species prevents us from drawing general conclusions. Using an insect species in which males make a large but variable parental investment in their offspring, we use two indicators of immunocompetence to test the hypothesis that sex-biased immunity is determined by differences in parental investment. We found that when the value of paternal investment was experimentally increased, male immune investment became relatively greater than that of females. Thus, in this system, in which the direction of sexual competition is plastic, the direction of sex-biased immunity is also plastic and appears to track relative parental investment.

scholarly journals The measure and significance of Bateman's principles

2014 ◽  
Vol 281 (1782) ◽  
pp. 20132973 ◽  
Author(s):  
Julie M. Collet ◽  
Rebecca F. Dean ◽  
Kirsty Worley ◽  
David S. Richardson ◽  
Tommaso Pizzari
Keyword(s):  
Reproductive Success ◽  
Mating Success ◽  
Male Reproductive Success ◽  
Female Fecundity ◽  
Male Preference ◽  
Bateman Gradient ◽  
Red Junglefowl ◽  
Experimental Approaches ◽  
Empirical Tests ◽  
Paternity Share

Bateman's principles explain sex roles and sexual dimorphism through sex-specific variance in mating success, reproductive success and their relationships within sexes (Bateman gradients). Empirical tests of these principles, however, have come under intense scrutiny. Here, we experimentally show that in replicate groups of red junglefowl, Gallus gallus , mating and reproductive successes were more variable in males than in females, resulting in a steeper male Bateman gradient, consistent with Bateman's principles. However, we use novel quantitative techniques to reveal that current methods typically overestimate Bateman's principles because they (i) infer mating success indirectly from offspring parentage, and thus miss matings that fail to result in fertilization, and (ii) measure Bateman gradients through the univariate regression of reproductive over mating success, without considering the substantial influence of other components of male reproductive success, namely female fecundity and paternity share. We also find a significant female Bateman gradient but show that this likely emerges as spurious consequences of male preference for fecund females, emphasizing the need for experimental approaches to establish the causal relationship between reproductive and mating success. While providing qualitative support for Bateman's principles, our study demonstrates how current approaches can generate a misleading view of sex differences and roles.

scholarly journals Parental Investment and Mate Value

2018 ◽  
Author(s):  
Jan Antfolk ◽  
Agneta Sjölund
Keyword(s):  
Parental Investment ◽  
Maternal Investment ◽  
Paternal Investment ◽  
Mate Value ◽  
Reproductive Behaviors ◽  
Men And Women ◽  
Positive Correlation ◽  
Adult Men ◽  
Childhood Environment

Stressors in the childhood environment, such as decreased parental investment (PI) regulates an individual’s reproductive behaviors. The effect of these behaviors on fitness is partly determined by individual mate value (MV). We tested whether PI during childhood is associated to MV in adulthood. Adult men and women (N = 1244) reported received maternal and paternal investment, and also current MV. We found that high PI in childhood was associated with increased MV in adulthood. Additionally, there was a positive correlation between maternal and paternal investment and the association between paternal investment and MV was mediated through maternal investment. We conclude that PI, especially maternal investment, might influence MV in offspring.

Number and Size of Offspring

2021 ◽  
pp. 115-128
Author(s):  
Jeffrey A. Hutchings
Keyword(s):  
Life History ◽  
Clutch Size ◽  
Parental Investment ◽  
Adaptive Significance ◽  
Offspring Size ◽  
Structural Constraints ◽  
Offspring Survival ◽  
Trade Off ◽  
Offspring Number ◽  
Parental Fitness

Offspring number and size are two of the most variable life-history traits. Among species, much of this variability can be attributed to genetic, developmental, physiological, or structural constraints. Some trait combinations are not possible because of differences associated with a species’ evolutionary history. Substantial variation in propagule number and size can exist among populations of the same species, generating questions concerning the adaptive significance of this variability. The most influential models are those attributed to Lack on clutch size and to Smith and Fretwell on offspring size. Fundamental to both sets of models is a trade-off between offspring number and parental investment per offspring. When offspring survival or fitness continuously varies with offspring size, the fitness of the parent depends on both offspring size and the number of offspring of that size that the parent can produce. If offspring survival is independent of offspring size, parental fitness is maximized when individuals maximize the production of minimally sized propagules.

scholarly journals Low but genetically variable male remating ability in a tropical Drosophila despite substantial fitness benefits

2018 ◽  
Author(s):  
Andrew D. Saxon ◽  
Natalie E. Jones ◽  
Eleanor K. O’Brien ◽  
Jon R. Bridle
Keyword(s):  
Genetic Variation ◽  
Mating Success ◽  
Local Population ◽  
Encounter Rate ◽  
Male Reproductive Success ◽  
Male Mating ◽  
Heritable Variation ◽  
Elevational Gradients ◽  
Offspring Number ◽  
Mating Latency

AbstractMating success is the main source of fitness variation in males, meaning that males should capitalise on all opportunities for mating. Strong selection on male mating success should also reduce genetic variation in male mating traits relative to other traits. We quantified mating latency, mating duration and productivity in males of the tropical fruitfly, Drosophila birchii, from 30 isofemale lines collected from across two elevational gradients, when they were given opportunities to mate with up to four females consecutively. Male remating rates were low compared to other Drosophila (only 14 – 27% of males achieved a fourth mating), with mean mating durations approximately doubling across successive copulations. However, although successive remating produced progressively fewer offspring, it consistently increased overall male reproductive success, with males that mated four times more than doubling offspring number compared to males mating only once. We also found no reduction in the productivity of sons emerging from later matings, indicating a sustained cumulative fitness benefit to remating. Heritable variation was observed for most traits (H2 = 0.035 – 0.292) except mating latency, but there was no divergence in trait means with elevation. The observed restricted remating ability of male D. birchii, despite the clear benefits of remating, may be due to a low encounter rate with females in the field, leading to high investment per gamete (or ejaculate). However, it remains unclear why genetic variation in these traits is high, given we observe no variation in these traits across elevational gradients known to affect local population density.

PATERNAL INVESTMENT AND STATUS-RELATED CHILD OUTCOMES: TIMING OF FATHER'S DEATH AFFECTS OFFSPRING SUCCESS

2012 ◽  
Vol 44 (5) ◽  
pp. 549-569 ◽  
Author(s):  
MARY K. SHENK ◽  
BROOKE A. SCELZA
Keyword(s):  
Parental Investment ◽  
Negative Impact ◽  
Child Outcomes ◽  
Child Survival ◽  
Father Absence ◽  
Late Childhood ◽  
Paternal Investment ◽  
Negative Effects ◽  
Adult Status ◽  
And Child Health

SummaryRecent work in human behavioural ecology has suggested that analyses focusing on early childhood may underestimate the importance of paternal investment to child outcomes since such investment may not become crucial until adolescence or beyond. This may be especially important in societies with a heritable component to status, as later investment by fathers may be more strongly related to a child's adult status than early forms of parental investment that affect child survival and child health. In such circumstances, the death or absence of a father may have profoundly negative effects on the adult outcomes of his children that cannot be easily compensated for by the investment of mothers or other relatives. This proposition is tested using a multigenerational dataset from Bangalore, India, containing information on paternal mortality as well as several child outcomes dependent on parental investment during adolescence and young adulthood. The paper examines the effects of paternal death, and the timing of paternal death, on a child's education, adult income, age at marriage and the amount spent on his or her marriage, along with similar characteristics of spouses. Results indicate that a father's death has a negative impact on child outcomes, and that, in contrast to some findings in the literature on father absence, the effects of paternal death are strongest for children who lose their father in late childhood or adolescence.

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