scholarly journals Maternal Condition, Reproductive Investment, and Offspring Sex Ratio in Captive Red Junglefowl (Gallus gallus)

The Auk ◽  
2002 ◽  
Vol 119 (3) ◽  
pp. 840-845 ◽  
Author(s):  
Timothy H. Parker
Keyword(s):  
Reproductive Success ◽  
Egg Size ◽  
Reproductive Investment ◽  
Gallus Gallus ◽  
Male Reproductive Success ◽  
Maternal Condition ◽  
Offspring Sex Ratio ◽  
Red Junglefowl ◽  
Offspring Sex ◽  
The Relationship

Abstract Maternal condition can affect reproductive investment in one or more ways. Captive female Red Junglefowl (Gallus gallus) that were heavier, controlling for tarsus length, produced larger eggs and initiated laying earlier, but did not produce more eggs per clutch. Maternal mass was also a positive predictor of offspring mass. That appears to result from the strong positive relationships between egg size and offspring mass. When the relationship between egg size and offspring mass was statistically controlled, maternal mass no longer predicted offspring mass. Mothers in better condition produced male-biased broods, as predicted when offspring condition depends on maternal condition and when male reproductive success is more dependent than female reproductive success on condition.

scholarly journals Seasonal Variation in Sex Ratios Provides Developmental Advantages in White-tailed Deer, Odocoileus virginianus

2007 ◽  
Vol 121 (4) ◽  
pp. 412
Author(s):  
Sarah T. Saalfeld ◽  
Stephen S. Ditchkoff ◽  
John J. Ozoga ◽  
Michael S. Mitchell
Keyword(s):  
Reproductive Success ◽  
Odocoileus Virginianus ◽  
Mammalian Species ◽  
Sex Ratios ◽  
Reproductive Potential ◽  
Birth Date ◽  
Male Reproductive Success ◽  
Maternal Condition ◽  
Offspring Sex Ratio ◽  
Offspring Sex

Since Trivers and Willard first proposed their hypothesis concerning the adaptive advantages of producing a particular offspring sex in relation to maternal condition in 1973, it has been at the forefront of scientific research concerning sex ratios with most subsequent studies focusing on maternal condition as a key contributor to variations in sex ratios. Another factor that could greatly influence sex ratios, although has been only infrequently examined in mammalian species, is birth date. We investigated how birth date influenced offspring sex ratios in White-tailed Deer (Odocoileus virginianus). Since date of birth can greatly influence an individual’s fitness and reproductive success, we suggest that birth date may be an alternative strategy in determining offspring sex ratios. Since it has been shown that the lifetime reproductive fitness of a mother can be increased by producing a particular sex during a particular time, we hypothesized that more male offspring should be born earlier in the season due to their increased reproductive potential from being born at this time. Offspring born earlier will have a head start in development and therefore have greater potential for increased body size and dominance later in life, traits that greatly influence male reproductive success. In this study, we found that maternal condition did not affect offspring sex ratio in a captive population of White-tailed Deer in Michigan; however, birth date did. We found that more males tended to be born during the second and fourth birthing periods, while more females were born during the first, third and fifth periods. In addition, we found that males born earlier in the season had greater mass the following spring than those born later, a trend that was not as dramatic in females. These results lend moderate support to our hypothesis that in White-tailed Deer offspring sex will tend to vary according to timing of birth and relative reproductive advantages gained by a particular sex being born at that time.

scholarly journals Surplus nest boxes and the potential for polygyny affect clutch size and offspring sex ratio in house wrens

2006 ◽  
Vol 273 (1595) ◽  
pp. 1751-1757 ◽  
Author(s):  
Natalie S Dubois ◽  
E Dale Kennedy ◽  
Thomas Getty
Keyword(s):  
Reproductive Investment ◽  
Male Reproductive Success ◽  
Offspring Sex Ratio ◽  
House Wrens ◽  
Nest Boxes ◽  
Cavity Nesting ◽  
Offspring Sex ◽  
Investment In Reproduction ◽  
Male House

Females of many species can gain benefits from being choosy about their mates and even exhibit context-dependent investment in reproduction in response to the quality of their breeding situation. Here, we show that if a male house wren is provided with surplus nest boxes in his territory, his mate lays a larger clutch with a significantly higher proportion of sons. This response to a territory characteristic directly associated with male competitive ability, and ultimately to male reproductive success, suggests that male competition over access to high-quality territories with surplus nest boxes (i.e. those able to support polygyny) may influence female reproductive investment decisions. The results of this study have interesting implications, particularly considering the important role that studies of cavity nesting birds utilizing nest boxes have played in advancing our understanding of behaviour, ecology and evolution.

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.

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

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.

scholarly journals Increase in Male Reproductive Success and Female Reproductive Investment in Invasive Populations of the Harlequin Ladybird Harmonia axyridis

PLoS ONE ◽  
2013 ◽  
Vol 8 (10) ◽  
pp. e77083 ◽  
Author(s):  
Guillaume J. M. Laugier ◽  
Gilles Le Moguédec ◽  
Ashraf Tayeh ◽  
Anne Loiseau ◽  
Naoya Osawa ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Harmonia Axyridis ◽  
Reproductive Investment ◽  
Male Reproductive Success ◽  
Harlequin Ladybird
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