Maternal corticosterone exposure has transgenerational effects on grand-offspring

The hormone fluctuations that an animal experiences during ovulation can have lifelong effects on developing offspring. These hormones may act as an adaptive mechanism, allowing offspring to be ‘pre-programmed’ to survive in an unstable environment. Here, we used a transgenerational approach to examine the effects of elevated maternal corticosterone (CORT) on the future reproductive success of female offspring. We show that female zebra finches ( Taeniopygia guttata ) exposed to embryonic CORT produce daughters that have equal reproductive success (clutch sizes, fertility, hatching success) compared with the daughters produced from untreated mothers, but their offspring had accelerated post-hatching growth rates and were significantly heavier by nutritional independence. Although there was no significant effect on primary offspring sex ratio, females from CORT-treated mothers produced significantly female-biased clutches by nutritional independence. To the best of our knowledge, this is the first record of a transgenerational sex ratio bias in response to elevated maternal CORT in any avian species.

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Adjustment of fecundity and sex ratio in response to social environments in a haplodiploid mite

Systematic and Applied Acarology ◽

10.11158/saa.27.1.7 ◽

2022 ◽

Author(s):

Nuwan Weerawansha ◽

Qiao Wang ◽

Xiong Zhao He

Keyword(s):

Population Density ◽

Sex Ratio ◽

Population Size ◽

Local Population ◽

Female Offspring ◽

Social Environments ◽

Positive Interaction ◽

Offspring Sex Ratio ◽

Offspring Sex ◽

Large Populations

Animals can adjust reproductive strategies in favour of corporation or competition in response to local population size and density, the two key factors of social environments. However, previous studies usually focus on either population size or density but ignore their interactions. Using a haplodiploid spider mite, Tetranychus ludeni Zacher, we carried out a factorial experiment in the laboratory to examine how ovipositing females adjust their fecundity and offspring sex ratio during their early reproductive life under various population size and density. We reveal that females laid significantly more eggs with increasing population size and significantly fewer eggs with increasing population density. This suggests that large populations favour cooperation between individuals and dense populations increase competition. We demonstrate a significant negative interaction of population size and density that resulted in significantly fewer eggs laid in the large and dense populations. Furthermore, we show that females significantly skewed the offspring sex ratio towards female-biased in small populations to reduce the local mate competition among their sons. However, population density incurred no significant impact on offspring sex ratio, while the significant positive interaction of population size and density significantly increased the proportion of female offspring in the large and dense populations, which will minimise food or space competition as females usually disperse after mating at crowded conditions. These results also suggest that population density affecting sex allocation in T. ludeni is intercorrelated with population size. This study provides evidence that animals can manipulate their reproductive output and adjust offspring sex ratio in response to various social environments, and the interactions of different socio-environmental factors may play significant roles.

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Consistent sex ratio bias of individual female dragon lizards

Biology Letters ◽

10.1098/rsbl.2006.0526 ◽

2006 ◽

Vol 2 (4) ◽

pp. 569-572 ◽

Cited By ~ 24

Author(s):

Tobias Uller ◽

Beth Mott ◽

Gaetano Odierna ◽

Mats Olsson

Keyword(s):

Genetic Variation ◽

Sex Ratio ◽

Incubation Temperature ◽

Sex Ratios ◽

Phenotypic Traits ◽

Female Size ◽

Offspring Sex Ratio ◽

Phenotypic Differences ◽

Sex Ratio Bias ◽

Offspring Sex

Sex ratio evolution relies on genetic variation in either the phenotypic traits that influence sex ratios or sex-determining mechanisms. However, consistent variation among females in offspring sex ratio is rarely investigated. Here, we show that female painted dragons ( Ctenophorus pictus ) have highly repeatable sex ratios among clutches within years. A consistent effect of female identity could represent stable phenotypic differences among females or genetic variation in sex-determining mechanisms. Sex ratios were not correlated with female size, body condition or coloration. Furthermore, sex ratios were not influenced by incubation temperature. However, the variation among females resulted in female-biased mean population sex ratios at hatching both within and among years.

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The Effects of Polygyny and Domicility on Offspring Sex Ratio in Ghana

African and Asian Studies ◽

10.1163/156921007x236972 ◽

2007 ◽

Vol 6 (4) ◽

pp. 431-456

Author(s):

Adansi Amankwaa

Keyword(s):

Sex Ratio ◽

Family Structure ◽

Living Arrangements ◽

Living Arrangement ◽

Demographic And Health Surveys ◽

Offspring Sex Ratio ◽

Ratio Bias ◽

Sex Ratio Bias ◽

Offspring Sex ◽

The Relationship

AbstractThis article explores how family structure and domicility influences offspring sex ratio bias, specifically living arrangements of husband in polygynous unions. Data from three Ghana Demographic and Health Surveys were used to examine the relationship between family structure and offspring sex ratio at birth, something that previous studies have not been able to do. This study estimate models of sex ratio offspring if the wives live together with husband present and wives live in separate dwellings and are visited by husband in turn. The results suggest that within polygynous marriages there are more male births, especially when husbands reside in the same dwelling as wives, than when husbands reside in separate dwellings from their wives. The analyses show that offspring sex ratio is related to the structure of living arrangement of husbands in polygynous unions. Indeed, the findings suggest that living arrangements and family structure among humans are important factors in predicting offspring sex ratio bias.

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Breeding ecology and bias in offspring sex ratio in little grassbirds (Megalurus gramineus)

Australian Journal of Zoology ◽

10.1071/zo03002 ◽

2003 ◽

Vol 51 (5) ◽

pp. 505 ◽

Cited By ~ 5

Author(s):

Rebecca R. McIntosh ◽

Romke Kats ◽

Mathew Berg ◽

Jan Komdeur ◽

Mark A. Elgar

Keyword(s):

Sex Ratio ◽

Breeding Season ◽

Salt Marshes ◽

Sex Allocation ◽

Breeding Ecology ◽

Offspring Sex Ratio ◽

Reed Beds ◽

Primary Sex Ratio ◽

Sex Ratio Bias ◽

Offspring Sex

Little grassbirds (Megalurus gramineus) are small, sexually monomorphic passerines that live in reed beds, lignum swamps and salt marshes in southern Australia. The breeding biology and patterns of sex allocation of the little grassbird were investigated over a single breeding season. Our observations of this species in the Edithvale Wetland Reserve revealed a highly male-biased population sex ratio, with some breeding territories containing several additional males. Nevertheless, there was little compelling evidence that little grassbirds breed cooperatively. The growth rates of male and female nestlings were similar and, as predicted by theory, there was no overall primary sex ratio bias. However, the primary sex ratio was female-biased early in the breeding season and became increasingly male-biased later in the breeding season.

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The proportion of blue light affects parasitoid wasp behavior in LED-extended photoperiod in greenhouses: Increased parasitism and offspring sex ratio bias

Biological Control ◽

10.1016/j.biocontrol.2019.03.004 ◽

2019 ◽

Vol 133 ◽

pp. 9-17 ◽

Cited By ~ 1

Author(s):

Précillia Cochard ◽

Tigran Galstian ◽

Conrad Cloutier

Keyword(s):

Sex Ratio ◽

Blue Light ◽

Parasitoid Wasp ◽

Offspring Sex Ratio ◽

Ratio Bias ◽

Sex Ratio Bias ◽

Offspring Sex ◽

Wasp Behavior

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An unstable social environment affects sex ratio in guinea pigs: an adaptive maternal effect?

Behaviour ◽

10.1163/156853909x445579 ◽

2009 ◽

Vol 146 (11) ◽

pp. 1513-1529 ◽

Cited By ~ 11

Author(s):

Nikolaus Von Engelhardt ◽

Sylvia Kaiser ◽

Norbert Sachser ◽

Kristina Kemme ◽

Ton Groothuis ◽

...

Keyword(s):

Reproductive Success ◽

Sex Ratio ◽

Social Environment ◽

Guinea Pigs ◽

Social Situation ◽

Offspring Sex Ratio ◽

Social Instability ◽

Environmental Disasters ◽

Offspring Sex ◽

Secondary Sex Ratio

AbstractEvolutionary theory suggests that offspring sex should be adjusted to environmental conditions in order to maximize future reproductive success. In several animal taxa environmental factors indeed affect the secondary sex ratio. In humans, changes in the sex ratio at birth have been associated with population stressors like war, environmental disasters or economic strife during pregnancy. Here we compared litter sex ratios of female guinea pigs, exposed experimentally to a stable and an unstable social environment. In the latter group composition was changed every three days. Under unstable social conditions the sex ratio was significantly more biased towards daughters than in the stable social situation. This finding was consistent among four independent experiments, conducted independently from each other. Life expectancy can be dramatically reduced under conditions of social instability. Hence mothers in such conditions should bias their investment towards the sex that reaches sexual maturity first, which is the female sex in this species. Thus, to shift the offspring sex ratio towards more daughters under conditions of social instability may represent a maternal strategy to maximize future reproductive success.

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Offspring sex ratio shifts of the solitary parasitoid wasp, Trichopria drosophilae (Hymenoptera: Diapriidae), under local mate competition

Entomologica Fennica ◽

10.33338/ef.71221 ◽

2018 ◽

Vol 29 (2) ◽

pp. 97-104 ◽

Cited By ~ 1

Author(s):

Jing Li ◽

Yu Wang ◽

Cheng-Jie Zhu ◽

Min Zhang ◽

Hao-Yuan Hu

Keyword(s):

Sex Ratio ◽

Parasitoid Wasp ◽

Female Offspring ◽

Mate Competition ◽

Offspring Sex Ratio ◽

Pupal Parasitoid ◽

Offspring Sex ◽

Local Mate ◽

Solitary Parasitoid ◽

Single Foundress

Localmate competition (LMC) models predict a female-biased offspring sex ratio when a single foundress oviposits alone in a patch and an increasing proportion of sons with increasing foundress number. We tested whether the solitary pupal parasitoid, Trichopria drosophilae (Hymenoptera: Diapriidae), adjusted offspring sex ratio with foundress number when parasitizing Drosophila melanogaster pupae. Mean number of female offspring was higher than that of males, with a male proportion of 26 ± 16% when only one foundress oviposited. However, male proportion reached 58 ± 26%, 48 ± 22%, and 51 ± 19% in three-, five and seven-foundress cohorts. That the male proportion of offspring increased with foundress number is consistent with LMC models.

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Socioeconomic status influences sex ratios in a Chinese rural population

PeerJ ◽

10.7717/peerj.3546 ◽

2017 ◽

Vol 5 ◽

pp. e3546 ◽

Cited By ~ 1

Author(s):

Liqun Luo ◽

Rui Ding ◽

Xiali Gao ◽

Jingjing Sun ◽

Wei Zhao

Keyword(s):

Socioeconomic Status ◽

Reproductive Success ◽

Sex Ratio ◽

Rural Population ◽

Northern China ◽

High Status ◽

Offspring Sex Ratio ◽

Family Socioeconomic Status ◽

Offspring Sex ◽

Study Population

According to the logic of the Trivers–Willard hypothesis, in a human population, if socioeconomic status is transmitted across generations to some extent, and if sons of high-status parents tend to have higher reproductive success than daughters, while daughters of low-status parents tend to have higher reproductive success than sons, then we should expect that offspring sex ratio is positively associated with socioeconomic status. This study examines whether the assumptions and prediction of this hypothesis apply to a rural population in northern China. Results show that (1) current family socioeconomic status is positively related to family head’s father’s socioeconomic status in around 1950, (2) low-status family heads have more grandchildren through their daughters than their sons, whereas high- or middle-status family heads have more grandchildren through sons, and (3) as family heads’ status increases, they tend to produce a higher offspring sex ratio. Therefore, the assumptions and prediction of the hypothesis are met in the study population. These results are discussed in reference to past studies on sex ratio manipulation among humans.

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