scholarly journals The Relationship between Hatching Time and Sex-ratio in Chicks

1973 ◽  
Vol 52 (4) ◽  
pp. 1584-1592 ◽  
Author(s):  
Kenji Ichinoe
Author(s):  
Ma. Dulce C. Guillena

Gonado-somatic index and fecundity are tools for measuring the sexual maturity and ability of animals to reproduce.  This study investigates the reproduction of Trichiurus lepturus. Specifically, this aimed to determine the sex ratio, the GSI, the relationship between fecundity and total length, fecundity and total weight, fecundity and ovary weight. The Descriptive Method of research was used.  Percentage and chi-square was utilized in determining the percentage of occurrence and sex ratio respectively.   Pearson r Product Moment Coefficient of Correlation was used to determine the relationships of the parameters. The study revealed that females outnumbered males and the sex ratio for different month showed significant difference.  Spawning season was observed to occur in November and December as revealed in its GSI values and it synchronized with the full and new moon phases.  Fecundity is positively correlated with body weight, body size, and ovary weight where ovary weight is observed to be the best index for fecundity.  The results of this study could be used further for formal stock assessment of cutlassfish fishery.


1972 ◽  
Vol 9 (2) ◽  
pp. 102-103
Author(s):  
Kenji Ichinoe ◽  
Osamu Yamamuro ◽  
Shozo Suzuki

2019 ◽  
pp. 137-142
Author(s):  
Baaloudj Affef

Urothemis edwardsii is one of the most threatened dragonfly species in the Mediterranean. Recent investigations and conservation efforts have increased the local geographic distribution of the species in Northeast Algeria, where a new population (named El Graeate) has been discovered. In the absence of information about the biology and behavior of U. edwardsii in this new site, a study was conducted on the emergence ecology of the species taking into account the temporal pattern of emergence, sex ratio, body size and microhabitat selection. Emergence, which was quite asynchronous, lasted for 50 days, with 50% of the population emerging within the first half of the period. Sex ratio at emergence was slightly female biased despite the absence of sexual size dimorphism, suggesting that size is not the only driving force behind mortality bias during the larval stage. There was a slight seasonal increase in the body size of exuviae (exoskeletons) in both sexes. Microhabitat selection, assessed as the vertical stratification of exuviae at ecdysis, was positively correlated with the height of supporting plants, but the relationship reached a plateau suggesting that there are predetermined limits to the vertical distribution of exuviae. These data will be essential for the future species protection, restoration and management attempts in the region.


Omni-Akuatika ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Rugaya Serosero ◽  
Sulistiono Sulistiono ◽  
Nurlisa A. Butet ◽  
Etty Riani

Coconut crab (Birgus latro) is a crustacean that has a large size until four kilograms. The study  aimed to analyze sex ratio and growth pattern including the relationship of thorax length - body weight, thorax width - body weight and cephalothorax length plus rostrum - body weight in Daeo (Morotai Island), Laigoma (South Halmahera District) and Fitako (North Halmahera District). The sex ratio was determined using χ2 test and the growth pattern was tested by the b value through t test. The results showed sex ratio of 1: 0.9 in Daeo (n = 581), 1: 0.6 in Laigoma (n = 24), and 1: 2 in Fitako (n = 31). The relationship of thorax length, thorax width and cephalothorax length plus rostrum with body weight were strongly correlated (R2> 70%). The growth pattern of coconut crab in Daeo was negative allometric, while in Laigoma and Fitako were negative allometric and isometric.


2020 ◽  
Vol 9 (2) ◽  
pp. 35
Author(s):  
Yendraliza Yendraliza ◽  
Muhamad Rodiallah ◽  
Zumarni Zumarni

This study was conducted to determine the relationship of birth weight of calves, sex ratio of the calves, and the age of the dam to the length of pregnancy in buffaloes resulting from artificial insemination in Kampar District. The method used in this research is the descriptive method by displaying the average and standard deviation. The total number of buffaloes that were artificially inseminated in 2018 and gave birth in 2019 was 21 buffalo-cows. Data were analyzed with the Pearson Product Moment (PPM) correlation. The parameters measured in this study were the length of pregnancy, calf birth weight, calf sex ratio, and dam’s age. The results showed a positive correlation between the birth weight of the calves, sex ratio of the calves, and the age of the dam to the length of pregnancy of 1.4%, with an average length of pregnancy, calf birth weight, and sex ratio of 351.81 days, 27.38 kg, and 1: 1 respectively.


2007 ◽  
Vol 6 (4) ◽  
pp. 431-456
Author(s):  
Adansi Amankwaa

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.


1974 ◽  
Vol 106 (1) ◽  
pp. 1-10 ◽  
Author(s):  
L. A. Lyons ◽  
C. R. Sullivan

AbstractIn Neodiprion sertifer (Geoff.), mortality is greater in males than in females in the egg stage and probably also among early larvae, but in the late larval period females are more susceptible. The evidence consists of the difference in mortality between all-male and mixed (male + female) colonies, as well as the relationship of secondary sex ratio to preceding mortality and the number of survivors per colony. The effect of differential mortality on estimation of the primary sex ratio is discussed.


1971 ◽  
Vol 3 (1) ◽  
pp. 23-42 ◽  
Author(s):  
Michael S. Teitelbaum ◽  
Nathan Mantel

Using a large special study population and refined indicators of socio-economic status, the relationship of the live birth sex ratio to socio economic variables is examined. The analyses provide control for the possible confounding effects of race and birth order.The sex ratio is shown to be significantly and positively associated with socio-economic variables. The relationship is not linear, however, but instead is characterized by an apparent ‘diminishing returns’ curve. The major increase in sex ratio is detected as socio-economic status increases from low to moderate. No significant change occurs between moderate and higher socio-economic levels.Even after controlling for the significant socio-economic effect, the analyses detect a significant difference between the sex ratios of Whites on the one hand and Negroes and Puerto Ricans on the other.No significant association between birth order and the sex ratio can be detected in the study population.


2017 ◽  
Vol 10 (2) ◽  
pp. 152-159 ◽  
Author(s):  
Nicholas P. Alt ◽  
Brianna Goodale ◽  
David J. Lick ◽  
Kerri L. Johnson

Everyday, we visually perceive people not only in isolation but also in groups. Yet, visual person perception research typically focuses on inferences made about isolated individuals. By integrating social vision and visual ensemble coding, we present novel evidence that (a) perceivers rapidly (500 ms) extract a group’s ratio of men to women and (b) both explicit judgments of threat and indirect evaluative priming of threat increase as the ratio of men to women in a group increases. Furthermore, participants’ estimates of the number of men, and not perceived men’s coalition, mediate the relationship between the ratio of men to women and threat judgments. These findings demonstrate the remarkable efficiency of perceiving a group’s sex ratio and downstream evaluative inferences made from these percepts. Overall, this work advances person perception research into the novel domain of people perception, revealing how the visually perceived sex ratio of groups impacts social judgments.


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