Impact of Adult Size and Sib, Conspecific, and Random Mating in Trichopria Sp. on Progeny Production and Sex Ratio

2015 ◽  
pp. 47-52
Author(s):  
N. Veena ◽  
D. Manjunath
Keyword(s):  
Sex Ratio ◽  
Random Mating ◽  
Adult Size ◽  
Progeny Production

Demography and Group Structure in Wedgecapped Capuchin Monkeys, Cebus Olivaceus

Behaviour ◽  
1988 ◽  
Vol 104 (3-4) ◽  
pp. 202-232 ◽  
Author(s):  
John G. Robinson
Keyword(s):  
Sex Ratio ◽  
Life Table ◽  
Group Structure ◽  
Age Distribution ◽  
Capuchin Monkeys ◽  
Demographic Parameters ◽  
Adult Size ◽  
Sex Composition ◽  
Cebus Olivaceus ◽  
Age And Sex

AbstractThe extent to which population demography determines the age and sex composition of primate groups was examined using data from a population of wedge-capped capuchin monkeys Cebus olivaceus in central Venezuela. Demographic parameters were derived from censuses of individually recognized, aged, and sexed individuals living in nine groups over a ten year period. Animals were aged by extrapolation from census data. Animals of both sexes were classed as infants during their first year, and juveniles until they reached six years of age. Females reach sexual maturity at this time, while males were classed as subadults until they reached full adult size at age 12. Adulthood lasts at least 30 years in females, at least 24 years in males. Age-sex class specific mortality and fecundity rates generated a life table which indicated that the population was increasing (r = 0.087) between 1977 and 1986. The age and sex composition of the nine groups was described annually. On average, non-adults made up 60% of a group, with this percentage increasing with group size. There were more females than males in all groups in all years. The strong female-biased adult sex ratio (1:4.4) was a consequence of a biased birth sex ratio (1:1.9), higher female than male survivorship especially between the ages of 3 and 7 when males were dispersing, and a pronounced sexual bimaturism. The stable age distribution derived from the life table successfully predicted the observed average distribution of age-sex categories in groups. This suggests that the group structure of Cebus olivaceus groups is not a consequence of intragroup social interactions, but results from demographic parameters.

scholarly journals Sex allocation in haplodiploids is mediated by egg size: evidence in the spider mite Tetranychus urticae Koch

2010 ◽  
Vol 278 (1708) ◽  
pp. 1054-1063 ◽  
Author(s):  
Emilie Macke ◽  
Sara Magalhães ◽  
Hong Do-Thi Khan ◽  
Anthony Luciano ◽  
Adrien Frantz ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Tetranychus Urticae ◽  
Egg Size ◽  
Spider Mite ◽  
Sex Ratios ◽  
Size Difference ◽  
Adult Size ◽  
External Fertilization ◽  
Offspring Sex Ratio ◽  
Egg Provisioning

Haplodiploid species display extraordinary sex ratios. However, a differential investment in male and female offspring might also be achieved by a differential provisioning of eggs, as observed in birds and lizards. We investigated this hypothesis in the haplodiploid spider mite Tetranychus urticae , which displays highly female-biased sex ratios. We show that egg size significantly determines not only larval size, juvenile survival and adult size, but also fertilization probability, as in marine invertebrates with external fertilization, so that female (fertilized) eggs are significantly larger than male (unfertilized) eggs. Moreover, females with on average larger eggs before fertilization produce a more female-biased sex ratio afterwards. Egg size thus mediates sex-specific egg provisioning, sex and offspring sex ratio. Finally, sex-specific egg provisioning has another major consequence: male eggs produced by mated mothers are smaller than male eggs produced by virgins, and this size difference persists in adults. Virgin females might thus have a (male) fitness advantage over mated females.

Effect of Host Size on Adult Size and Sex Ratio of Bracon mellitor (Hymenoptera: Braconidae)

1993 ◽  
Vol 22 (5) ◽  
pp. 1161-1165 ◽  
Author(s):  
P. Glynn Tillman ◽  
James R. Cate
Keyword(s):  
Sex Ratio ◽  
Host Size ◽  
Adult Size ◽  
Bracon Mellitor

scholarly journals Effects of host and foundress density on reproductive strategy of Diaeretiella rapae

2012 ◽  
Vol 65 ◽  
pp. 294-294 ◽  
Author(s):  
R. Kant ◽  
M.A. Minor ◽  
S.A. Trewick ◽  
W.R.M. Sandanayaka
Keyword(s):  
Sex Ratio ◽  
Reproductive Strategy ◽  
Sex Allocation ◽  
Parasitic Wasp ◽  
Female Offspring ◽  
Reproductive Fitness ◽  
Brevicoryne Brassicae ◽  
Diaeretiella Rapae ◽  
Progeny Production ◽  
Total Parasitism

The reproductive fitness of a parasitoid depends on the oviposition decisions of a female in response to competition The present study investigated the oviposition and sex ratio of offspring produced by the parasitic wasp Diaeretiella rapae while competing with other conspecific females and at different host densities The number of Brevicoryne brassicae nymphs parasitised by female D rapae increased with the number of nymphs offered to them However the proportion of nymphs parasitised by the female decreased when nymph density was high The proportion of fertilised eggs oviposited by females decreased when nymph density increased An increase in the number of foundresses (females ovpositing together) increased the total parasitism but the contribution of each female (the number of nymphs each female parasitised) decreased Smaller proportions of female offspring were produced when females were competing for the same hosts The results of this study suggest that both host and foundress densities asymmetrically affect progeny production and sex allocation in this species

Proximate mechanisms responsible for random mating by size in the Himalayan toad Duttaphrynus himalayanus

2020 ◽  
pp. 1-13
Author(s):  
Lixia Zhang ◽  
Yongsun Sheng ◽  
Xiangyu Yuan ◽  
Fei Yu ◽  
Xueting Zhong ◽  
...  
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Female Body ◽  
Random Mating ◽  
Apparent Size ◽  
Operational Sex Ratio ◽  
Female Body Size ◽  
Short Period ◽  
Significant Difference ◽  
Duttaphrynus Himalayanus

Abstract Exploring the mechanisms that affect mating pattern with respect to body size has implications for understanding the evolution of sexual selection. Theory predicts that the absence of a relationship between female body size and fecundity, unbiased operational sex ratio, and a short breeding season will lead to random mating by body size in anuran amphibians. We tested these predictions in the Himalayan toad Duttaphrynus himalayanus inhabiting southeastern Tibet. Our study did not detect any correlation between female body size and number of eggs laid, nor was there a significant difference in the sex ratio of toads captured from the breeding site. In addition, the toads were reproductive for only a short period, from late April to early May (typical of an explosively breeding species). As expected, we detected a weak but not significant relationship between body size of amplexing males and females. Our results revealed no apparent size-assortative pairing in the study population of the Himalayan toad and may contribute to an increasing body of literature on mating patterns in relation to body size in animals with indeterminate growth.

scholarly journals Quality deterioration of mass reared offsprings of Bracon hebetor in successive generations

2016 ◽  
Vol 13 (2) ◽  
pp. 1-12
Author(s):  
MS Alam ◽  
MZ Alam ◽  
SN Alam ◽  
MRU Miah ◽  
MIH Mian ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Significant Variation ◽  
First Generation ◽  
Galleria Mellonella ◽  
Progeny Production ◽  
Bracon Hebetor ◽  
Sixth Generation ◽  
Male Sex ◽  
Successive Generations ◽  
Wax Moth

A study was undertaken to determine the generation-wise parasitizing efficiency of mass reared Bracon hebetor on wax moth (Galleria mellonella). Two experiments were conducted to achieve the objectives. In the first experiment, the host larvae and parasitoid were released in the field micro plot during first generation and reared in the laboratory in subsequent generations. In another experiment, all generations were developed in the laboratory. In the first experiment, generation showed significant variation on sex ratio of adult progeny production. The male sex ratio increased with the range of 62.89 to 74.58% and female sex ratio declined ranging from 39 to 25% with the advancement of generations. The percent parasitization and adult progeny production was not influenced appreciably with the progress of generation. In the second experiment parasitization and adult progeny production did not vary significantly in successive generations. However there was a decreasing trend in parasitization from 95 to 55% by Bracon hebetor and adult progeny production by 47.5 to 15.5 adultsfemale-110 larvae-1 over generation. The sex ratio of adult progeny was significantly influenced by inbreed generation in laboratory reared population. Female decrease in sex ratio from first to sixth generation was 39.25 to 16.88%.SAARC J. Agri., 13(2): 1-12 (2015)

scholarly journals Is Evolution of Mating Preferences Inevitable? Random Mating in the Multisex System of Tetrahymena thermophila

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Sujal S. Phadke ◽  
Lauren Cooper ◽  
Rebecca A. Zufall
Keyword(s):  
Theoretical Model ◽  
Mate Choice ◽  
Sex Ratio ◽  
Sexual Differentiation ◽  
Mating Systems ◽  
Tetrahymena Thermophila ◽  
Random Mating ◽  
Maximum Amount ◽  
Mating Preferences ◽  
Mechanistic Basis

Ciliate mating systems are highly diversified, providing unique opportunities to study sexual differentiation and its implications for mating dynamics. Many species of ciliates have multiple (>2) sexes. More sexes may mean more choice and an opportunity for evolution of preferential mating. We asked if the multiple sexes of the ciliate Tetrahymena thermophila mate preferentially among each other. We quantified pairing frequencies among four sexes of T. thermophila using experiments that allowed the sexes to compete as mating partners. We found that all sexes mated equally frequently among each other, that is, we found no evidence of preferential mating with respect to sex. This suggests that the “mate choice” in this ciliate is binary, between whether to form a pair or not and, in this regard, sex facilitates only self-/non-self-distinction. Thus, presence of multiple sexes does not necessarily result in the evolution of mating bias, which could decrease the maximum amount of mating that would otherwise be possible in a population. Our result of random mating verifies a key assumption in the theoretical model of sex ratio evolution in T. thermophila. Investigation into molecular differences between the sexes will be necessary to reveal the mechanistic basis of random mating among them.

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