scholarly journals Male soldier caste larvae are non-aggressive in the polyembryonic wasp Copidosoma floridanum

2007 ◽  
Vol 3 (4) ◽  
pp. 431-434 ◽  
Author(s):  
David Giron ◽  
Jeffrey A Harvey ◽  
Jena Anne Johnson ◽  
Michael R Strand
Keyword(s):  
Sex Ratio ◽  
Mating System ◽  
Male And Female ◽  
Copidosoma Floridanum ◽  
Males And Females ◽  
Female Soldiers

Polyembryonic wasps are the only parasitoids in which sociality has evolved. Theory implicates both competition and sex ratio manipulation in the evolution of a sterile soldier caste. However, investment in soldiers by males and females is predicted to differ depending upon how offspring are allocated to hosts and the mating system. Here, we compared male and female soldiers in the polyembryonic wasp Copidosoma floridanum . We found that male and female soldiers are morphologically identical. Unlike females, however, male soldiers were non-aggressive towards all competitors. We discuss these results in relation to theory and polyembryonic wasp biology.

Routine Infanticide by Married Couples? An Assessment of Baptismal Records from Seventeenth Century Parma

2011 ◽  
Vol 15 (6) ◽  
pp. 507-530 ◽  
Author(s):  
Laura Hynes
Keyword(s):  
Seventeenth Century ◽  
Sex Ratio ◽  
Economic Status ◽  
Married Couples ◽  
Sex Ratio At Birth ◽  
Male And Female ◽  
Socio Economic Status ◽  
Rural And Urban ◽  
Italian City ◽  
Males And Females

Abstract This study uses baptismal records from the Italian city of Parma from 1609 to 1637 to chart the sex ratio of male and female infants at baptism. This article measures the Parman sex ratio against the natural sex ratio at birth for live-born infants, as determined by Praven Visaria, and offers preliminary findings that indicate that married couples used infanticide as a means of controlling family size and sex in seventeenth-century Parma. The 28 years studied encompass both relatively strong economic and agricultural years as well as a variety of crises. By selecting a period with both good and bad economic years it is possible to see if parents behaved differently as their household conditions varied. Further, dividing the approximately 30,000 baptisms by rural and urban jurisdictions and familial socio-economic status makes visible parental recourse to infanticide through unnatural ratios of males and females within different segments of society.

scholarly journals Investigating the interaction between inter-locus and intra-locus sexual conflict using hemiclonal analysis in Drosophila melanogaster

2021 ◽  
Author(s):  
Manas Geeta Arun ◽  
Tejinder Singh Chechi ◽  
Rakesh Meena ◽  
Shradha Dattaraya Bhosle ◽  
Srishti ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sex Ratio ◽  
Genetic Correlation ◽  
Empirical Evidence ◽  
Sexual Conflict ◽  
Genetic Basis ◽  
Operational Sex Ratio ◽  
Female Fitness ◽  
Male And Female ◽  
Males And Females

Divergence in the evolutionary interests of males and females leads to sexual conflict. Traditionally, sexual conflict has been classified into two types: inter-locus sexual conflict (IeSC) and intra-locus sexual conflict (IaSC). IeSC is modeled as a conflict over outcomes of intersexual reproductive interactions mediated by loci that are sex-limited in their effects. IaSC is thought to be a product of selection acting in opposite directions in males and females on traits with a common underlying genetic basis. While in their canonical formalisms IaSC and IeSC are mutually exclusive, there is growing support for the idea that the two may interact. Empirical evidence for such interactions, however, is limited. Here, we investigated the interaction between IeSC and IaSC in Drosophila melanogaster. Using hemiclonal analysis, we sampled 39 hemigenomes from a laboratory-adapted population of D. melanogaster. We measured the contribution of each hemigenome to adult male and female fitness at three different intensities of IeSC, obtained by varying the operational sex-ratio. Subsequently, we estimated the intensity of IaSC at each sex-ratio by calculating the intersexual genetic correlation for fitness and the proportion of sexually antagonistic fitness-variation. Our results indicate a statistically non-significant trend suggesting that increasing the strength of IeSC ameliorates IaSC in the population.

Sex Behaviour and Sex Determination in Crepidula Fornicata L

1959 ◽  
Vol 36 (1) ◽  
pp. 34-39
Author(s):  
JAN Z. WILCZYNSKI
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Sea Water ◽  
Male And Female ◽  
Crepidula Fornicata ◽  
Naturally Occurring ◽  
Significant Tendency ◽  
Males And Females

1. The percentages of males and females in naturally occurring chains of Crepidula fornicata L. were found to be 39% females, 6% ‘transients’ and 55% males. 2. Disconnected males kept in cages in sea water for 9 months re-established the normal sex ratio. 3. Disconnected males were kept for periods of 4-6 weeks at temperatures of 30° and 10° C. No significant tendency to change sex was observed. 4. Males were injected with extracts of females. No tendency to change sex was observed. 5. In animals of all sizes from small males to large females both male and female gametes are invariably present together. The gametes of both sexes are polymorphic.

scholarly journals Sex determination in crayfish: are intersex Cherax quadricarinatus (Decapoda, Parastacidae) genetically females?

2003 ◽  
Vol 82 (2) ◽  
pp. 107-116 ◽  
Author(s):  
S. PARNES ◽  
I. KHALAILA ◽  
G. HULATA ◽  
A. SAGI
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Genetic Basis ◽  
Male And Female ◽  
Cherax Quadricarinatus ◽  
Male Ratio ◽  
Males And Females ◽  
Normal Males ◽  
Red Claw Crayfish ◽  
Female Genital

In the Australian red-claw crayfish Cherax quadricarinatus (von Martens) (Decapoda, Parastacidae), a gonochoristic species, seven different combinations of intersex individuals (with both male and female genital openings) have been described. However, to date, the genetic basis for this phenomenon has not been investigated. This study was designed to test a simple chromosome-based sex-determination model for C. quadricarinatus that assumes the male to be the homogametic (ZZ) sex. According to our model, intersex individuals that are functionally males are genetically females (WZ). Individual crosses were performed between intersex and female crayfish, with control crosses being performed between normal males and females. The control crosses yielded, in most cases, the expected 1[ratio ]1 sex ratio in the F1 progeny. Crosses between intersex individuals and females yielded a 1[ratio ]3 (male[ratio ]female) sex ratio in most crosses. According to our hypothesis, one-third of the females produced in a cross of a female with an intersex animal should be WW females. The hypothesis was tested by crossing normal males with F1 females, which were progeny of intersex fathers. These crosses yielded almost 100% females, a finding that conforms to the above-suggested sex determination model for C. quadricarinatus and the female WZ genotype of intersex individuals.

Maintenance of androdioecy in the freshwater clam shrimp Eulimnadia texana: longevity of males relative to hermaphrodites

2001 ◽  
Vol 79 (3) ◽  
pp. 393-401 ◽  
Author(s):  
Naida Zucker ◽  
Brian Stafki ◽  
Stephen C Weeks
Keyword(s):  
Sex Ratio ◽  
Mating System ◽  
Mixed Mating ◽  
Mixed Mating System ◽  
Freshwater Clam ◽  
Behavioral Observations ◽  
Clam Shrimp ◽  
Rearing Conditions ◽  
Mating Opportunities ◽  
Males And Females

The clam shrimp Eulimnadia texana exhibits a rare mixed mating system known as androdioecy. In this ephemeral-pond branchiopod crustacean, males coexist with hermaphrodites, which can outcross with males or self-fertilize. We provide an estimate of the longevity of males relative to hermaphrodites (1 – σ), an important parameter of a model that was developed to explain the conditions under which this system would be stable. Under both optimal rearing conditions and various sex-ratio treatments, hermaphrodites from two study populations lived significantly longer than males. Since various aspects of mating have been found to be costly to males and females/hermaphrodites in other taxa, we explored this possibility as well. Hermaphrodites showed no differences in longevity when kept in groups provided with different mating opportunities. Males, however, lived significantly longer when mating opportunities were increased, a result contrary to what we had expected. Behavioral observations, however, suggested that male–male interactions may have been deleterious to males living in groups with little opportunity to mate. This was confirmed by an additional study in which individual males were maintained in the presence and absence of hermaphrodites. Under these conditions we still detected no longevity cost of mating for males.

scholarly journals PERBANDINGAN JENIS KELAMIN DAN DIMORFISME SEKSUAL PADA PERTUMBUHAN IKAN GURAMI (Osphronemus goramy) SERTA IMPLIKASINYA TERHADAP STRATEGI SELEKSINYA

2017 ◽  
Vol 11 (4) ◽  
pp. 307 ◽  
Author(s):  
Sularto Sularto ◽  
Rita Febrianti ◽  
Suharyanto Suharyanto
Keyword(s):  
Sex Ratio ◽  
Standard Length ◽  
Adult Size ◽  
Male Fish ◽  
Male And Female ◽  
Fish Breeding ◽  
Significant Difference ◽  
Different Populations ◽  
Males And Females ◽  
Number Of Males

Ikan gurami (Osphronemus goramy Lac.) pada ukuran dewasa memiliki bentuk morfometrik yang khas khususnya pada ikan jantan, sehingga dapat dibedakan antara ikan jantan dan betina. Ikan gurami jantan memiliki dahi menonjol dan bibir tebal. Penelitian ini bertujuan untuk mengevaluasi rasio kelamin dan perbedaan performa pertumbuhan antara jantan dan betina. Ikan uji yang digunakan adalah empat populasi ikan gurami yang berbeda yaitu: Kalimantan Selatan, Jambi, Majalengka, dan Tasikmalaya. Penelitian dilaksanakan di Balai Penelitian Pemuliaan Ikan (BPPI), Sukamandi pada bulan Juni 2014 sampai dengan bulan Juli 2015. Hewan uji yang digunakan adalah benih ikan gurami keturunan galur murni berasal dari Kalimantan Selatan, Jambi (strain Batanghari), Majalengka, dan Tasikmalaya. Perawatan telur, pemeliharaan benih, dan pembesaran menggunakan prosedur operasional standar BPPI tentang pemeliharaan ikan gurami. Pemeliharaan ikan gurami dilakukan selama 14 bulan. Hasil penelitian menunjukkan bahwa berdasarkan jenis kelaminnya jumlah ikan gurami betina (67,3%-80,7%) lebih banyak dibandingkan dengan jumlah jantannya (19,3%-32,7%). Setelah mencapai ukuran > 300 g terdapat perbedaan pertumbuhan antara ikan jantan dan betina (P<0,05) yakni jantan tumbuh lebih cepat dibandingkan betina pada semua populasi yakni berkisar antara 4,74%-5,67% untuk karakter panjang standar, dan 14,10%-16,52% untuk karakter bobot. Hal tersebut menunjukkan bahwa ikan gurami memiliki dimorfisme pertumbuhan. Oleh karena itu, ketika dilakukan seleksi berdasarkan pertumbuhan 10% terbaik didapatkan ikan jantan 55%-80% lebih banyak dibandingkan ikan betina (20%-45%).Adult size of giant gouramy (Osphronemus goramy, Lac.) has a distinctive shape of morphometric particularly in male fish, making it easy to distinguish between male and female fishes. Giant gouramy males have a prominent forehead and thick lips. This study aimed to determine sex ratios and differences in growth performance between males and females. This study used 4 progenies of giant gouramy seed from four different populations, namely: Kalimantan, Jambi, Majalengka, and Tasikmalaya, aged 14 months. Eggs incubations,seed maintenance and grow-out were conducted using Standard Operational Procedures of Research Institute for Fish Breeding (RIFB) about the rearing of giant gouramy. Seed rearing were carried out for 14 months. The results showed that, based upon the sex ratio, the number of female was more than the number of males, contituting females 67.3%–80.7% and males from 19.3% to 32.7% of populations. After reaching the size of > 300 g there were a significant difference in growth between males and females (P <0.05), in which males grew faster than females in all populations between 4.74%–5.67% for the standard length and 14.10%–16.52% for the weight characters. IThis result indicated that giant gouramy have growth dimorphism.Therefore, when the selection conducted based on the best growth of top 10%, it was found that the number of male composing 55%–80% was higher than the number of female which only accounted for 20%–45%.

scholarly journals PERTUMBUHAN, FAKTOR KONDISI, DAN BEBERAPA ASPEK REPRODUKSI IKAN LEMURU (Amblygaster sirm, Walbaum 1792) DI PERAIRAN SELAT SUNDA

2017 ◽  
Vol 9 (1) ◽  
pp. 43
Author(s):  
Nidya Kartini ◽  
Mennofatria Boer ◽  
Ridwan Affandi
Keyword(s):  
Sex Ratio ◽  
Condition Factor ◽  
Growth Parameters ◽  
Sampling Technique ◽  
Biological Information ◽  
Male And Female ◽  
Conservation Measure ◽  
Males And Females ◽  
First Maturity ◽  
Size At First Maturity

Ikan lemuru (Amblygaster sirm) merupakan salah satu komiditas utama di Selat Sunda yang menjadi target nelayan di Pelabuhan Perikanan Pantai Lebuan. Informasi biologi dibutuhkan untuk menyusun langkah konservasi ikan lemuru. Penelitian ini bertujuan untuk menganalisis kondisi biologis ikan lemuru di perairan Selat Sunda melalui pengkajian parameter pertumbuhan, faktor kondisi, dan beberapa aspek reproduksi. Pengambilan ikan contoh dilakukan pada bulan April-Agustus 2015 dari hasil tangkapan nelayan yang didaratkan di PPP Labuan, Banten menggunakan teknik Penarikan Contoh Acak Berlapis. Jumlah ikan contoh yang diambil selama penelitian sebanyak 527 ekor ikan jantan dan 245 ekor ikan betina. Hasil penelitian menunjukkan bahwa pola pertumbuhan ikan lemuru jantan dan betina adalah isometrik, nilai faktor kondisi ikan lemuru jantan berkisar 0,9346 – 1,0294 dan betina berkisar 0,9401 – 1,0738, parameter pertumbuhan L∞, K, dan t0 pada ikan jantan adalah 248,80 mm; 0,24/tahun;dan -0,38. Adapun parameter (L∞, K, dan t0) pada ikan betina adalah 235,26 mm; 0,46/tahun, dan -0,20. Nisbah kelamin ikan lemuru jantan dan betina TKG IV adalah 0,75:1. Ukuran pertama kali matang gonad (Lm) ikan lemuru jantan dan betina adalah 188 mm dan 186 mm. Sedangkan ukuran pertama kali tertangkap (Lc) ikan lemuru jantan dan betina adalah 172 mm dan 173 mm. Musim pemijahan ikan lemuru diduga terjadi pada bulan Mei dan Juli.The spotted sardinella (Amblygaster sirm) was one of main commodities in the Sunda Strait that maily targeted by fishers in Labuan Coastal Fishing Port, Banten. The biological  information  needed to setup conservation measure of the spotted sardinella. This research aims to analyse the biological conditions of spotted sardinella in the Sunda Strait by reviewing parameters of growth, condition factor, and some reproduction aspect. Research was conducted in April-August 2015 in Labuan Coastal Fishing Port, Banten by using Random Stratified Sampling technique. About 700 samples (527 male and 245 female fishes) collected during study. The results showed that the growth pattern of male and female were isometric, value of condition factor for male ranged from 0,9346 – 1,0294 and for female ranged from 0,9401 – 1,0738. The estimated growth parameters (L∞, K, and t0) for male were 248,80 mm; 0,24 year-1;and -0,38 respectively. While, the parameters (L∞, K, and t0) of female were 235,26 mm; 0,46 year-1;and -0,20 respectively. The sex ratio between males and females for spotted sardinella was 0,75:1. The size at first maturity (Lm) of male and female were 188 mm and 186 mm, respectively. In addition, the size a first caught (Lc) of male and female was 172 mm and 173 mm, respectively. Thespawning season spotted sardinella possibly occurs in May and July.

scholarly journals Gonad maturity of simping Placuna placenta, Linn 1758 (Bivalve: Placunidae) harvested from Kronjo Coastal, Indonesia

2019 ◽  
Vol 5 (1) ◽  
pp. 26-37
Author(s):  
Yon Yonvitner ◽  
Isdradjad Setyobudiandi ◽  
Rokhmin Dahuri ◽  
Jamilah Jamilah
Keyword(s):  
Sex Ratio ◽  
Shallow Water ◽  
Shell Length ◽  
Raw Material ◽  
Mature Stage ◽  
Male And Female ◽  
Gonad Maturity ◽  
Coastal Resource ◽  
Males And Females

Simping (P. placenta) is a coastal resource found in shallow water with a muddy substrate. Simping widely used as a source of food and as raw material for the decoration.  Utilization of simping until now has not yet focused on recruitment, reproductive aspect. This information is important as a basis data for determining the size of the simping catch. This study aimed to find out about of reproduction aspect, determining sex ratio the size of the catch simping. This research was conduct for three months at 3 locations. The number of samples in the analysis is 36 species to determine sex ratio and gonad maturity.  Sex ratio indifferent from male and female, but based on the time sex ratio of simping significant, both male and female. The length size of gonads shellfish matures form 5.50 cm and 5.85 cm at 2 TKG conditions. Length of simping mature from 6.08 cm, 6.24 cm, 6.45 cm and 7.11 cm dominant at TKG mature stage 3,  and 8.61 cm dominant at 4 TKG conditions. Sex ratio reaches 6 cm shell length and not significant between males and females (M: F=1;1).  It is concluded that  the level of maturity of gonads increases  with increasing of simping size. 

scholarly journals Female Fatality due to Cholera was Higher than Male. Studies of Four Cholera Epidemics in the Poznań Province in the Second Half of the 19th Century.

2021 ◽  
Author(s):  
GRAŻYNA LICZBIŃSKA ◽  
Miroslav Králík
Keyword(s):  
Sex Ratio ◽  
Contaminated Water ◽  
Death Rates ◽  
Male And Female ◽  
Empirical Distributions ◽  
Males And Females ◽  
Causes Of Deaths ◽  
The 19Th Century ◽  
Male To Female ◽  
Gender Specific

Abstract Background: Males and females differ in terms of patterns of morbidity and mortality resulting from diseases.Objectives: It has been tested whether cholera epidemics killed selectively by sex in historical populations. Four cholera epidemics in the Poznań Province: 1852, 1855, 1866, and 1873 have been studied.Data sources: Data have been derived from death registers of the selected parishes located on the territory of the Poznań Province. In total, the information about 34, 655 individual cases, with the causes of deaths recognized, has been used, encompassing 18,243 males and 16,325 females. Methods: The daily and weekly incidences of cholera deaths have been counted for epidemics in 1852, 1855, 1866 and 1873. The relations of male-to-female deaths numbers by epidemiological weeks have been computed. The sex ratio at death (SRD) and sex ratio at death from cholera (SRDCh) have been calculated. The differences between the theoretical and empirical distributions in the numbers of male and female deaths, deaths from cholera, SRD and SRDCh have been examined. Results: More females than males died in the periods of cholera epidemics than in non- epidemic ones. The values of SRDCh during the earlier epidemics (1852, 1855) and later epidemics (1866, 1873) were 0.91 and 0.97, respectively. A significant variances in the sex-specific death ratio have been observed between the cholera epidemics periods (SRD=0.89) and non-epidemic periods (SRD=1.13) in Poznań.Conclusions: The gender-specific cholera death rates could have been related to the division of social roles between women and men. Women more frequently than men had contact with contaminated water, e.g. when preparing and cooking meals, feeding, caring for and washing children and caring for sick family members.

Sex Ratios and Sex Allocation

2001 ◽  
Author(s):  
Steven Hecht Orzack
Keyword(s):  
Sex Ratio ◽  
Sex Allocation ◽  
Female Flower ◽  
Reproductive Organs ◽  
Evolutionary Analysis ◽  
Male And Female ◽  
Sex Ratio Theory ◽  
Males And Females ◽  
Descent Of Man ◽  
Evolutionary Aspects

Understanding the allocation of energy is the goal of the evolutionary analysis of sex allocation. Whether one is concerned with the relative sizes of male and female flower parts in plants like those discussed by Campbell (1998), the ratio of males and females in insects like those discussed by Orzack et al. (1991), or the relative sizes of male and female reproductive organs in hermaphroditic fish like those discussed by Leonard (1993), one is concerned with how energy allocated toward reproduction is apportioned into one sex as opposed to the other (or more in the case of some kinds of organisms). Here, the sexes are entities that at regular or irregular intervals produce gametes, some of which come together to produce zygotes. The abstract nature of this description underscores the degree to which there are common evolutionary aspects to all of these problems, despite the fact that the biological details involved are so diverse. One of the most influential and important agendas for evolutionary studies of sex allocation was laid out by Charnov (1982). He described the underlying evolutionary similarities between phenomena as diverse as sex change in shrimp and sex ratio in vertebrates like us. Even more important, he promoted sex allocation as a central evolutionary problem by describing how seemingly unrelated allocation problems could all be analyzed with a kind of mathematical approach elaborated by Shaw and Mohler (1953). I consider in turn four important examples of this approach. Shaw and Mohler’s goal was to understand the evolution of the proportions of males and females. This problem of the sex ratio was most famously addressed by Darwin in his 1871 book, The Descent of Man, and Selection in Relation to Sex, as well as by others in the subsequent decades. The most influential analysis is that of Fisher (1930); however, Carl Düsing, who worked in the 1880s, can rightly be regarded as the progenitor of modern sex ratio theory (see Edwards 1998).

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