Maternal Investment in Adolescent Daughters and Sons

2021 ◽  
pp. 279-304
Author(s):  
Mary B. Eberly Lewis ◽  
Trinity Hoenig
Keyword(s):  
Reproductive Success ◽  
Maternal Investment ◽  
Knowledge And Skills ◽  
Competitive Success ◽  
Local Ecology ◽  
Sexually Mature

This chapter reflects on maternal investment in adolescent daughters and sons. The focus of maternal investment necessarily changes as a function of the ontological maturity of adolescent sons and daughters. As most sexually mature youth continue to live with parents, mothers’ investments channel youth toward adaptive trajectories given the opportunities and constraints of the local ecology. The nature of childrearing shifts to a greater emphasis on preparing daughters and sons for socio-competitive success; that is, providing resources, particularly those that increase adult knowledge and skills, and protecting offspring from their own adventurousness while learning occurs. Through this focus, mothers facilitate the reproductive success of offspring.

scholarly journals Giraffe males have longer suckling bouts than females

2019 ◽  
Vol 101 (2) ◽  
pp. 558-563
Author(s):  
Markéta Gloneková ◽  
Karolína Brandlová ◽  
Jan Pluháček
Keyword(s):  
Czech Republic ◽  
Reproductive Success ◽  
Future Development ◽  
High Intensity ◽  
Maternal Investment ◽  
Female Offspring ◽  
Giraffa Camelopardalis ◽  
The Czech Republic ◽  
Selection For ◽  
The Difference

Abstract In polygynous mammals, females are expected to bias maternal investment in favor of male calves. The mother should invest more in males to enhance their reproductive success in adulthood, or the males require greater investment as they are bigger and stronger than females. In this study, we used nursing duration to compare the difference in the amount of maternal investment provided by females. We compared differences according to sex of the offspring and the influence of calves’ identification by sniffing, using captive giraffes (Giraffa camelopardalis) as a model. Since a high intensity of allonursing (nursing of a nonfilial calf) was reported in giraffes, we also focused on the difference between filial and nonfilial calves. We observed 22 nursing females and 47 suckling calves in four zoological gardens in the Czech Republic from 2007 to 2011. Nursing duration was longer for male calves than for female calves and for calves sniffed by the nursing female regardless whether the calves were filial or nonfilial. We conclude that male calves are more demanding for the amount of investment received and they are more successful in this effort than female calves. Since females provided investment in the same way to filial and nonfilial calves, selection for higher demand for investment by male than by female offspring should be important for their future development. Our results also demonstrate the importance of sniffing for the identification of the suckling calf by the female.

scholarly journals Vocal Transmission of Breeding Status May Facilitate Dispersal in a Cooperative Breeding Primate

2019 ◽  
Author(s):  
Efstathia Robakis ◽  
Gideon Erkenswick ◽  
Mrinalini Watsa
Keyword(s):  
Reproductive Success ◽  
Cooperative Breeding ◽  
Partner Choice ◽  
Reproductive Suppression ◽  
Neighboring Group ◽  
Vocal Signals ◽  
Mating Opportunities ◽  
One Year ◽  
Sexually Mature ◽  
Breeding Status

Social complexity may drive complexity in communicative systems due to an individual's need to navigate unpredictable interactions with multiple conspecifics. Cooperative breeding primates (marmosets and tamarins; family: Callitrichidae) live in groups with moderate to high reproductive skew, particularly in females, whereby sexually mature individuals are frequently prevented from breeding. Remarkably, dispersal from natal groups is not stereotyped upon reaching reproductive maturity. Individuals are often observed remaining in their natal groups until the same-sex breeder in their group or a neighboring group dies, experiencing hormonal reproductive suppression, aggression, and limited access to potential mates. Here we examined whether emperor tamarins (Saguinus imperator) might use vocal signals to reduce dispersal risks and maximize the likelihood of attaining a breeding position. Using six consecutive years of mark-recapture data, we showed that sexually mature non-breeders (herein "secondary breeders") are more likely to leave their groups from one year to the next than sexually mature breeders ("primary breeders"). This confirmed that, unlike primary breeders who do not need to disperse in order to reproduce, secondary breeders are choosing to accept the risks associated with dispersal and emigrating from their natal groups. We used neural networks to classify vocalizations according to individual breeding status, and conducted a series of playback experiments which demonstrated that tamarins discriminated between the calls of primary and secondary breeders. Our data support the hypotheses that secondary breeders disperse to increase mating opportunities and use vocalizations to signal their availability to potential mates. This species of cooperative breeder appears to use vocalization to navigate its social and reproductive systems, minimizing risks of dispersal and in turn increasing the likelihood of reproductive success. This research has important implications for our understanding of sexual signaling, partner choice, and reproductive success in cooperative breeders.

scholarly journals The bold and the sperm: positive association between boldness and sperm number in the guppy

2019 ◽  
Vol 6 (7) ◽  
pp. 190474 ◽  
Author(s):  
Clelia Gasparini ◽  
Elizabeth M. Speechley ◽  
Giovanni Polverino
Keyword(s):  
Reproductive Success ◽  
Personality Traits ◽  
Sperm Competition ◽  
Poecilia Reticulata ◽  
Positive Association ◽  
Sperm Number ◽  
Sperm Velocity ◽  
Fitness Consequences ◽  
Competitive Success ◽  
Sperm Traits

Assessing the consequences of personality traits on reproductive success is one of the most important challenges in personality studies and critical to understand the evolutionary implications of behavioural variability among animals. Personality traits are typically associated with mating acquisition in males, and, hence, linked to variation in their reproductive success. However, in most species, sexual selection continues after mating, and sperm traits (such as sperm number and quality) become very important in determining post-mating competitive success. Here, we investigate whether variation in personality traits is associated with variation in sperm traits using the guppy ( Poecilia reticulata ), a species with high levels of sperm competition. We found a positive association between boldness and sperm number but not sperm velocity, suggesting that bolder males have increased post-copulatory success than shyer individuals. No association was found between exploration and sperm traits. Our work highlights the importance of considering post-copulatory traits when investigating fitness consequences of personality traits, especially in species with high levels of female multiple matings and hence sperm competition.

scholarly journals Susceptibility of the male fitness phenotype to spontaneous mutation

2011 ◽  
Vol 8 (3) ◽  
pp. 426-429 ◽  
Author(s):  
Martin A. Mallet ◽  
Christopher M. Kimber ◽  
Adam K. Chippindale
Keyword(s):  
Reproductive Success ◽  
Large Fraction ◽  
Spontaneous Mutation ◽  
Reproductive Traits ◽  
Good Genes ◽  
Male Reproductive Success ◽  
Male Fitness ◽  
Adult Fitness ◽  
Competitive Success ◽  
Rate Of Decline

Adult reproductive success can account for a large fraction of male fitness, however, we know relatively little about the susceptibility of reproductive traits to mutation-accumulation (MA). Estimates of the mutational rate of decline for adult fitness and its components are controversial in Drosophila melanogaster , and post-copulatory performance has not been examined. We therefore separately measured the consequences of MA for total male reproductive success and its major pre-copulatory and post-copulatory components: mating success and sperm competitive success. We also measured juvenile viability, an important fitness component that has been well studied in MA experiments. MA had strongly deleterious effects on both male viability and adult fitness, but the latter declined at a much greater rate. Mutational pressure on total fitness is thus much greater than would be predicted by viability alone. We also noted a significant and positive correlation between all adult traits and viability in the MA lines, suggesting pleiotropy of mutational effect as required by ‘good genes’ models of sexual selection.

scholarly journals BIRTH INTERVAL AND THE SEX OF CHILDREN IN A TRADITIONAL AFRICAN POPULATION: AN EVOLUTIONARY ANALYSIS

1997 ◽  
Vol 29 (4) ◽  
pp. 499-507 ◽  
Author(s):  
RUTH MACE ◽  
REBECCA SEAR
Keyword(s):  
Reproductive Success ◽  
Parental Investment ◽  
Birth Interval ◽  
Reproductive Potential ◽  
Maternal Investment ◽  
African Population ◽  
Evolutionary Analysis ◽  
Birth Intervals ◽  
High Parity ◽  
Reproductive Decision Making

Birth interval is a major determinant of rates of fertility, and is also a measure of parental investment in a child. In this paper the length of the birth interval in a traditional African population is analysed by sex of children. Birth intervals after the birth of a boy were significantly longer than after the birth of a girl, indicating higher parental investment in boys. However, in women of high parity, this differential disappeared. Birth intervals for women with no son were shorter than for those with at least one son. All these results are compatible with an evolutionary analysis of reproductive decision-making. First born sons have particularly high reproductive success, daughters have average reproductive success and late born sons have low reproductive success. The birth interval follows a similar trend, suggesting that longer birth intervals represent higher maternal investment in children of high reproductive potential.

Size-related changes in winter condition of female and male reindeer calves

1996 ◽  
Vol 74 (6) ◽  
pp. 1174-1177 ◽  
Author(s):  
I. Kojola ◽  
T. Helle
Keyword(s):  
Sex Differences ◽  
Body Size ◽  
Reproductive Success ◽  
Sexual Activity ◽  
Rangifer Tarandus ◽  
Size Dependence ◽  
Maternal Investment ◽  
Winter Condition ◽  
Male And Female ◽  
Fat Reserves

This study investigated how relationships between body size and back-fat depth develop in female and male reindeer (Rangifer tarandus tarandus) calves in winter. Back-fat depths did not differ between male and female calves, but depended more strongly on body size in female calves. Because no sex difference was found in the post-rut sample (October), differences were not attributed to male puberty and consequent sexual activity. Sex differences might be related to the fact that female calves feed more often than males from craters dug in the snow by their mother and that daughters of dominant mothers share feeding craters with their mother most often. In the last sample month, February, the fattest males were medium-sized, but mean back-fat depths did not differ between medium-sized and large calves. The decreasing trend in size dependence of fat reserves of male calves through the winter possibly weakens the link between maternal investment and reproductive success of sons.

scholarly journals Maternal investment and reproductive success in Chinese water deer

2009 ◽  
Vol 55 (2) ◽  
pp. 102-110 ◽  
Author(s):  
Christiane Mauget ◽  
Robert Mauget
Keyword(s):  
Reproductive Success ◽  
Sexual Difference ◽  
Maternal Investment ◽  
Mass Gain ◽  
First Year ◽  
Lactation Period ◽  
Small Species ◽  
Chinese Water ◽  
Time Spent Feeding ◽  
Reproductive Females

Abstract Among cervids, maternal investment, estimated as the amount of resources and care allocated to the offspring, was expected to be related to species body size. Therefore, maternal investment in a herd of captive Chinese water deer Hydropotes inermis, a relatively small species of cervid, was investigated over 3 years. Except during the lactation period, reproductive females spent about 2-fold more time resting than feeding. During lactation, the amount of time spent feeding increased highly (25.3 min/h during lactation vs 17.3 min/h during the gestation period). Females spent less than 30% of time in communal behaviours with offspring. They did not reject alien fawns during this care period. Frequency and duration of suckling events decreased exponentially from the second week onwards. More than 10% of suckling bouts were non-filial. Prenatal investment leads to a mean litter mass (about 12% of maternal mass) higher than in most cervid species. Postnatal investment in fawns represents a daily mass gain of ca. 85 g/d during the first 2 weeks, without any sexual difference. Female production, timing and synchrony of births and survival of fawns characterized reproductive success. Seventy percent of mature females gave birth, with a mean of 1.9 offspring per female. The sex ratio was even. Births were synchronous, 80% of births occurring in 25 days. In this herd, 0.74 fawn per female was successfully weaned and 0.56 fawn per female survived through their first year. Based on these results we conclude that reproductive strategy of Chinese water deer was efficient and characterized by mother-offspring relationships typical of hiders and high levels of pre- and postnatal investments. This strategy seems typical of small species of cervids without marked sexual dimorphism.

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