On the Sex Ratio in Glossina

1952 ◽  
Vol 43 (2) ◽  
pp. 231-235 ◽  
Author(s):  
F. A. Squire
Keyword(s):  
Sex Ratio ◽  
Good Deal ◽  
Tsetse Fly ◽  
Reproductive Capacity ◽  
Female Ratio ◽  
The Past ◽  
Factors Influencing ◽  
Early Appearance ◽  
Age Factor ◽  
Male Female Ratio

The preponderance of males in tsetse-fly catches is an interesting fact that has not been understood in the past. Attention is drawn to the importance of the agefactor. Teneral flies are nearly always taken in equal numbers whereas non-teneral A.G.I flies and A.G.2 flies have the highest male/female ratio. In A.G.3, the ratio drops, indicating a decline in reproductive capacity. Females become fugitive about seven days after emergence, at the time when the first egg is almost due to descend into the uterus, i.e., at the end of the teneral stage. This is the mating phase par excellence. Mating is prolonged, vigorous, and frequent, and this accounts for the early appearance of the mating scars. As the uterus lies under and between the mating cushions, it is unsafe for females with eggs in the uterus or young larvae to mate. Third-instar larvae are safer as the highly chitinized polypneustic lobes take the brunt of the pummelling from the claspers. Safe periods also occur during the hiatus between larvipositions when the uterus is empty. There are, of course, other factors influencing the ratio, but the age factor is considered paramount, and failure to recognize this in the past has resulted in a good deal of confusion.

The Male : Female Ratio Among the Siblings of Delinquents

1975 ◽  
Vol 126 (3) ◽  
pp. 249-251 ◽  
Author(s):  
R. V. G. Clarke ◽  
P. Softley
Keyword(s):  
At Risk ◽  
Family Size ◽  
Good Deal ◽  
Female Ratio ◽  
The Family ◽  
Male Female Ratio ◽  
Male Activity

Those interested in the family backgrounds of delinquents have paid a good deal of attention to family size and position in family (see Mannheim, 1965, for a review), but little to the ratio of brothers to sisters. This is surprising, since it can be argued that boys who come from families with a preponderance of brothers may be particularly at risk of delinquency; for example, their parents might find it difficult to control them; they might be more likely to play out on the streets and thus have greater opportunities for delinquency; and, since delinquency is a predominantly male activity, they might have a greater chance of being set a bad example through the behaviour of their brothers.

Reproductive behaviour of female rosy bitterling Rhodeus ocellatus in response to a female-biased operational sex ratio

Behaviour ◽  
2014 ◽  
Vol 151 (6) ◽  
pp. 755-768 ◽  
Author(s):  
Caiping Liao ◽  
Dan Yu ◽  
Yiyu Chen ◽  
Martin Reichard ◽  
Huanzhang Liu
Keyword(s):  
Sex Ratio ◽  
Active Role ◽  
Reproductive Behaviour ◽  
Operational Sex Ratio ◽  
Reproductive Tactics ◽  
Female Ratio ◽  
Dominant Female ◽  
Male Female Ratio ◽  
Shaped Pattern ◽  
Rhodeus Ocellatus

While the effect of Operational Sex Ratio (OSR) on reproductive behaviour of males has been studied extensively, little is known of the response of females facing a female-biased OSR. We investigated the effect of different OSRs on female reproductive behaviour using the rosy bitterling, Rhodeus ocellatus, a freshwater fish that lays its eggs inside the gills of living freshwater mussels. Three levels of OSR (male/female ratio 1:1, 1:3 and 1:5) were tested. We demonstrated that inspection of the mussel (spawning substrate) by individual females increased with increasingly female-biased OSR, but that the rate of following territorial male decreased. Aggression towards other females was not affected by the OSR. Interestingly, when a male bitterling led a non-dominant female towards the mussel, the dominant female would become aggressive to the male and chase the non-dominant female away. Aggression towards male followed a bell-shaped pattern and was highest at an OSR of 1:3. In both the female-biased OSRs examined, almost 50% of dominant females tended to chase away other females and defend the mussel, showing territoriality in a similar manner to males. These observations suggest that female reproductive behaviour is strongly affected by the OSR, and their reproductive tactics during courtship change from a passive role in courtship (following a male) to an active role in courtship (approaching a male), with presence of female territorial behaviour as the OSR becomes increasingly female-biased. This study provides strong evidence that a female-biased OSR has an important effect on female reproductive behaviour.

Studies on the sex ratio of worms in schistosome infections

Parasitology ◽  
1990 ◽  
Vol 101 (1) ◽  
pp. 27-34 ◽  
Author(s):  
G. F. Mitchell ◽  
E. G. Garcia ◽  
S. M. Wood ◽  
R. Diasanta ◽  
R. Almonte ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Endemic Area ◽  
The Philippines ◽  
Mammalian Host ◽  
Late Time ◽  
Laboratory Mice ◽  
Female Ratio ◽  
Male Female Ratio ◽  
Duration Of Infection ◽  
Wild Rats

SUMMARYSex ratios of adult schistosomes in mice are almost invariably different from 1·0 and are biased towards males. The bias applies to wild rats infected with Schistosoma japonicum and trapped in an endemic area of the Philippines (male: female ratio = 1·7). It also applies to cercariae of snails collected in such areas and assessed by infection of laboratory mice using cercariae from individual snails (male: female ratio may approach 6·0). Experiments were designed to determine if duration of infection in the mammalian host was a factor that influenced the sex ratio of miracidia used for infecting snails and subsequently mice. BALB/c and C57BL/6 mice were infected with 100 cercariae of S. mansoni, and liver eggs harvested at early and late time points for infection of snails and production of cercariae. Two phenomena were demonstrated: firstly, a more pronounced male bias when eggs were harvested late compared with early in infection; secondly, a reduced apparent hatchability of eggs in BALB/c compared with C57BL/6 livers. The possibility is raised by the data that female miracidia within eggs of chronically infected individuals may be more prone to immune damage than male miracidia with important epidemiological consequences.

scholarly journals A clinical study to determine the effects of adenoidectomy in cases of secretory otitis media in school going children

2020 ◽  
Vol 5 (8) ◽  
pp. 200-206
Author(s):  
Dr. B Krishna Santosh ◽  
◽  
Dr. K Krishna Sumanth ◽  
Dr. Panda Veeranjaneyulu ◽  
Dr. B Deepthi ◽  
...  
Keyword(s):  
Otitis Media ◽  
Pure Tone ◽  
Pure Tone Audiometry ◽  
Secretory Otitis Media ◽  
Female Ratio ◽  
Impedance Audiometry ◽  
Tube Obstruction ◽  
The Past ◽  
Male Female Ratio ◽  
Ear Effusion

Introduction: Secretory Otitis media (SOM) is the leading cause of hearing loss in children. Despitenumerous studies on the prevention and treatment of SOM during the past decades, itsmanagement remains challenging and controversial. A study was conducted to find the effect ofadenoidectomy in cases of SOM with hypertrophied adenoids and to determine the effect ofadenoidectomy on hearing as assessed by the pure tone and impedance audiometry. Material andMethods: Children aged 5 – 12 years, diagnosed as SOM with adenoid hypertrophy were included.The study was conducted from April 2019 to May 2020, in the department of ENT, GSL MedicalCollege. A detailed history and clinical examination were done. Investigations such as pure toneaudiogram, impedance audiometry, X-ray nasopharynx, and diagnostic nasal endoscopy were carriedout to confirm the diagnosis. Results: Out of the 50 participants, a maximum (60%) belonged tothe 5 – 7 years age group, the male-female ratio was 1.2. Hard of hearing was a common symptomin 66%, tonsillitis, and sinusitis in 36% and 18% respectively. On pure tone audiometry, the averagehearing loss was 24.95dB. Conclusion: Adenoidectomy in children having hypertrophied adenoidswith SOM, not only relieves Eustachian tube obstruction but also removes the source of infection.This leads to clearance of middle ear effusion and improvement in hearing postoperatively.

The Sex Ratio and Rate of Reoperation for Dupuytren’s Contracture in Men and Women

1999 ◽  
Vol 24 (4) ◽  
pp. 456-459 ◽  
Author(s):  
S. WILBRAND ◽  
A. EKBOM ◽  
B. GERDIN
Keyword(s):  
Sex Ratio ◽  
Recurrent Disease ◽  
Hand Surgery ◽  
University Hospital ◽  
Early Age ◽  
Dupuytren’S Contracture ◽  
Female Ratio ◽  
Men And Women ◽  
Male Female Ratio ◽  
Repeated Surgery

We identified all patients treated by local fasciectomy at the Department of Hand Surgery, Uppsala University Hospital between 1965 and 1996. A total of 2375 operations were performed on 1600 patients. We found a male: female ratio of 5.9:1. Women had a higher mean age at first operation (62.4 years) than men (59.8 years). One-third of the men required repeated surgery and one-quarter of the women. Early age at first operation was associated with recurrent disease.

Suicide rates in Lusaka, Zambia: preliminary observations

1978 ◽  
Vol 8 (3) ◽  
pp. 423-432 ◽  
Author(s):  
G. G. C. Rwegellera
Keyword(s):  
Mental Illness ◽  
Age Differences ◽  
Significant Degree ◽  
Precipitating Factors ◽  
Female Ratio ◽  
The Past ◽  
Suicide Rates ◽  
Male Female Ratio ◽  
Physical Diseases

SynopsisThe records of all suicides and of all open verdicts in Lusaka (Zambia) over a 5-year period (1967–1971) were studied. The following suicide rates (per 100000 of the population per annum) were found: 7·4 for all races; 11·3 for men of all races; 3·0 for women of all races; 6·9 for all African residents; 11·2 for African males; 2·2 for African females; 12·8 for all Africans above the age of 14 years; 20·9 for all European residents; 20·7 for all European males; 21·0 for all European females. The male: female ratio among the Africans was 5:1. There was a tendency for the suicide rate among the Africans to rise with age. Differences in suicide rates between African and European residents were found not to be statistically significant. Though hanging was by far the most commonly used method of suicide by Africans, Europeans and ‘doubtful suicides’ among Africans preferred other methods to a statistically significant degree. It is suggested that the role of other methods in African suicides may well have been underestimated in the past. No definite seasonal variation in suicide rates was found. Domestic quarrels, mental illness and physical diseases would appear to be some of the important precipitating factors of suicide in Lusaka. It is also suggested that the question of whether or not suicide is rare in Africans cannot be answered until such time as when reliable figures are available in Africa.

scholarly journals Sex ratio and fecundity of Chrysichthys nigrodigitatus (Family - Claroteidae) from Asejire Lake, Nigeria

2021 ◽  
Vol 31 (1) ◽  
pp. 135-143
Author(s):  
I. O. Taiwo ◽  
O. Odunaiya
Keyword(s):  
Body Weight ◽  
Sex Ratio ◽  
Standard Length ◽  
Egg Production ◽  
Line Graph ◽  
Male Specimen ◽  
Female Ratio ◽  
Straight Line ◽  
Male Female Ratio ◽  
Average Size

Sex ratio and fecundity of Chrysichthys nigrodigitatus from Asejire Lake were examined. The length-weight relationship showed that weight was curvilinearly related to standard length. The logarithm transformation of weight against standard length gave a straight-line graph represented by the following equation: Log W = -0.66 + 2.13 Log sl r2= 0.854; (p<0.001) n = 209 Males were generally more with a male : female ratio of 1:0.18. The average fish weight was 88.97g (16.28 cm standard length). Sexual maturity was attained at an average size of 45.0g (14.0 cm standard length). Relative fecundity was dependent on body weight and standard length (P< 0.05 and P < 0.01 respectively). Chrysichthys nigrodigitatus expended between 0.75% - 27.30% of body weight in egg production. The condition factor values showed that a female specimen of equal length with a male specimen is heavier. Six gonad maturity stages were identified, ovary and gonad weights increased with stage of maturity.

INEQUALITY OF GENDER RATIO AMONG RELIGIOUS AND SOCIAL GROUPS IN INDIA

2016 ◽  
Vol 4 (2) ◽  
pp. 68 ◽  
Author(s):  
Sandipan R. Gavhale
Keyword(s):  
Sex Ratio ◽  
Gender Gap ◽  
Social Groups ◽  
Social Condition ◽  
Gender Ratio ◽  
Problematic Situation ◽  
Female Ratio ◽  
Economic Progress ◽  
The Social ◽  
Male Female Ratio

India was a mother-dominant country. But today, the atrocities event ratio and the gender gap in India have increased, which is serious and considerable matter. The male-female ratio in society is an indicator of the socio-economic progress of the country, considering this point, the social condition of India, is not improved by satisfactory.There are many social groups and various distinct cultures their effects become on unequal sex ratio this inequality exists into the upper caste. So this article focuses on class wise gender ratio in India as comparative gender ratio of SC, ST to another social group like upper caste. So this matter should be examined in thought level. Consequently, the social problems are increasing day after day, which should be studied by the thinkers to be improved from this problematic situation. 

Influence of sex ratio and sexual lability on seed production in the dioecious perennial shrub Atriplex amnicola (Chenopodiaceae)

1997 ◽  
Vol 37 (6) ◽  
pp. 661 ◽  
Author(s):  
M. Strawbridge ◽  
R. W. Bell ◽  
J. A. McComb ◽  
E. G. Barrett-Lennard
Keyword(s):  
Sex Ratio ◽  
Seed Production ◽  
Seed Quality ◽  
Seed Set ◽  
Dioecious Species ◽  
Female Ratio ◽  
Male Female Ratio ◽  
Perennial Shrub ◽  
Set Up ◽  
Field Plots

Summary. Pollen supply can limit seed set in dioecious species such as Atriplex amnicola Paul G. Wilson (river saltbush). Clonal populations, with 4 different male : female ratios (0 : 1, 1 : 8, 1 : 1 and 5 : 1), were set up in widely spaced field plots at Tammin, Western Australia. After 1 season, plants were examined for fruit fill and fruit germination. The optimal male : female ratio for Atriplex amnicola seed production was between 1 : 8 (11% males) and 1 : 1 (50% males). These ratios resulted in mean fruit fills of 24 and 36%, respectively. Genotype had a significant effect on fruit fill. The 3 clones tested had fruit fills of 40, 36 and 31%. These differences in fruit fill were as significant as those obtained from reducing the percentage of males from 50 to 11%. A population of 700 seedlings of A. amnicola examined over 5 years was shown to be sexually labile, with a slight decrease over time in males and an increase in females and monoecious plants. Sexual lability appeared to be linked to plant aging rather than to environmental stimuli. It was concluded that plantations of river saltbush set up for seed production should be planted with selected genotypes at a male : female ratio of between 1 : 8 and 1 : 1 and that plantations need to be monitored for change in sex ratio with time, to ratios suboptimal for seed quality and production.

A contribution to the biology of the burrowing mud shrimp, Callianassa subterranea (Decapoda: Thalassinidea)

1994 ◽  
Vol 74 (3) ◽  
pp. 623-635 ◽  
Author(s):  
A.A. Rowden ◽  
M.B. Jones
Keyword(s):  
Sex Ratio ◽  
Carapace Length ◽  
Sampling Period ◽  
Bimodal Distribution ◽  
Allometric Growth ◽  
Female Ratio ◽  
The North ◽  
Male Female Ratio ◽  
Mud Shrimp ◽  
Callianassa Subterranea

Samples of the mud shrimp Callianassa subterranea (Montagu) were taken at irregular intervals (September and October 1989, April and July 1990, August 1991) from a depth of 47 m at a fixed station in the North Sea (54°35′N 04°50′E). At this site, mud shrimps appear to have a contagious distribution, the mean density varied between 38 and 59 individuals m-2 and the sex ratio was biased significantly to males (mean male: female ratio, 1·9), except for shrimps of ≥8 mm carapace length (CL) which had an equal sex ratio. The combined samples for the full sampling period showed a bimodal distribution for males and females, with a possible third mode for males, suggesting a life cycle of between 2 and 3 years. Only females ≥7 mm CL carried eggs. Lack of samples over winter prevent any conclusive description of seasonal population patterns; however, reproduction (based on the presence of ovigerous females) extended from April to September with a peak in July and post-larval shrimps (<3 mm CL) were present each month. The allometric growth of the primary chela identified male (6·5 mm CL) and female (7·5 mm CL) size at maturity. Differences in allometric growth after maturity result in males having larger and more massive primary chelae than females of equal carapace length. The parasitic isopod Ione thoracica (Montagu) infected between 20% (October) and 10–8% (August) of mud shrimps, with males having a significantly higher level of infestation than females.

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