Reproduction of the biogenic reef-forming honeycomb worm Sabellaria alveolata in Ireland

2010 ◽  
Vol 90 (3) ◽  
pp. 503-507 ◽  
Author(s):  
S.C. Culloty ◽  
E. Favier ◽  
M. Ní Riada ◽  
N.F. Ramsay ◽  
R.M. O'Riordan
Keyword(s):  
Sex Ratio ◽  
Small Proportion ◽  
Sampling Period ◽  
Male And Female ◽  
Distinct Peak ◽  
Stage Of Development ◽  
South West ◽  
Female Gametogenesis

The stage of development of the gametes of both male and female honeycomb worms Sabellaria alveolata (L.) was examined, using histology, over a 14-month period. Samples came from Howes Strand and Garrettstown, County Cork in south-west Ireland. A clear cycle of both male and female gametogenesis was evident, with a distinct peak in the summer (June–September) when the majority of them were ripe. During October–January a small proportion of males contained abundant spermatozoa, but no mature oocytes were found. Over the whole sampling period the ratio of males:females was 1.4:1. Further south in Roches de la Fosse in France at the centre of its range, two spawnings and an even sex-ratio have been reported.

scholarly journals Reproductive Biological Performance of Otolithes ruber (Bloch and Schneider 1801) in San Miguel Bay, Philippines

2020 ◽  
pp. 127-136
Author(s):  
Noemi SB. Lanzuela ◽  
Errol M. Gallego ◽  
Jethro Emmanuel P. Baltar
Keyword(s):  
Sex Ratio ◽  
Reference Point ◽  
Sampling Period ◽  
Nursery Ground ◽  
Male And Female ◽  
Average Fecundity ◽  
Otolithes Ruber ◽  
Spawning Potential Ratio ◽  
Biological Performance ◽  
First Maturity

The tigertooth croaker, Otolithes ruber (Bloch and Schneider 1801), was studied to determine its reproductive biology characteristics for 34 months from March 2015 to November 2017. A total of 7,977 individuals were sampled and the measured total lengths (TL) ranged from 8.1 cm to 32.1 cm (16.70 ± 2.53 cm ) and 10.0 cm to 33.5 cm (17.95 ± 2.95 cm) for male and female, respectively. The length-weight relationship can be summarized as W = 0.00521 L3.18 and W = 0.00837 L3.01 for female and male, respectively. The length at first maturity of this species was determined to be 13.95 cm, which is smaller compared to other studies. The overall sex ratio of this species was 1:0.8, with males dominating the female sex (P < 0.05, X2 = 64.3). In addition, synchronized development of male and female gonads was observed. It was also verified that mature individuals were present all throughout the study period indicating that this species spawn continuously and the presence of juveniles during the sampling period indicated continuous recruitment. Mean monthly GSIs indicate July to November as the main spawning season of this species. The in-site occurrence of mature and juvenile stocks in the bay further implicates that San Miguel Bay is a nursery ground for this species. The fecundity varied between 3,420 to 422,100 with an average fecundity of 86,142 eggs. Lastly, the spawning potential ratio is still above the limit reference point (SPR = 0.36), indicating that the stock can still replenish their biomass.

scholarly journals Seasonal progression of sex ratio and phytoplasma infection in Scaphoideus titanus Ball (Hemiptera: Cicadellidae)

2008 ◽  
Vol 99 (4) ◽  
pp. 377-383 ◽  
Author(s):  
F. Lessio ◽  
R. Tedeschi ◽  
M. Pajoro ◽  
A. Alma
Keyword(s):  
Sex Ratio ◽  
Sampling Period ◽  
Seasonal Occurrence ◽  
Sticky Traps ◽  
Laboratory Rearing ◽  
Male And Female ◽  
Scaphoideus Titanus ◽  
Phytoplasma Infection ◽  
Males And Females ◽  
Sweep Net

AbstractThe differences between the seasonal occurrence and likelihood of being infected by FD phytoplasmas, of male and female Scaphoideus titanus Ball, were investigated. Sex ratio (male: female) was calculated by counting males and females sampled by means of yellow sticky traps and sweep-nets and from adults derived from hatched eggs in field-collected grapevine wood. PCR essays were performed to test differences in infection between genders. Overall, the sex ratio on sticky traps was significantly more male biased (1.99:1) if compared to net sweeping (0.62:1) and laboratory rearing (0.60:1). The peak of male presence was recorded in the middle of July in laboratory rearing and sweep net, and in the middle of August on sticky traps; the maximum presence of females was detected at the end of July in laboratory rearing, and at the end of August in sweep net samplings and on sticky traps. The seasonal sex ratio was more male biased at the beginning in laboratory rearing (1.50:1) and sticky traps (9:1), and then decreased in favor of females at the end of the sampling period, both in laboratory rearing (0.17:1) and in sticky traps (0.07:1). This trend was significantly less skewed, although similar, in sweep net samplings that recorded a sex ratio of 1:1 and 0.16:1 at the beginning and at the end of the sampling period, respectively. Concerning phytoplasma detection, an interaction between gender and sampling period was observed, the males showing a peak of infected individuals later in the season (35%). Some possible behavioral explanations of the data obtained are given.

scholarly journals REPRODUCTIVE ASPECTS OF SCALLOPED PERCHLET, Ambassis nalua (HAMILTON, 1822) IN PABEAN BAY INDRAMAYU, WEST JAVA

2017 ◽  
Vol 9 (1) ◽  
pp. 113-124 ◽  
Author(s):  
Nisha Desfi Arianti ◽  
M.F. Rahardjo ◽  
Ahmad Zahid
Keyword(s):  
Sex Ratio ◽  
Sampling Period ◽  
Spawning Season ◽  
Diameter Distribution ◽  
Male And Female ◽  
Fish Samples ◽  
Males And Females ◽  
Mature Fish ◽  
First Maturity ◽  
Egg Diameter

ABSTRACTScalloped perchlet, Ambassis nalua,  is one of fishes in Pabean Bay, Indramayu. This research aims to determine the reproductive aspects of Ambassis nalua in Pabean Bay Indramayu including sex ratio, spawning season, first maturity, fecundity and spawning pattern. Fish samples were collected by trap net and trammel net at three sites in Pabean Bay from April to October 2015. A total of 424 of A. nalua were caught, consist of 114 males and 310 females; with total length ranged from 38.04 to 112.63 mm and total weight ranged from 0.37 to 25.44 g. Sex ratio of mature fish  was 1:1.9. The mature males and females were found in every month of sampling period. The gonado-somatic index (GSI) ranged from 0.40 to 0.83 and 2.36 to 4.54 for male and female, respectively. The peak of spawning season was found in September. The first maturity (Lm50) for male and female were 79.17 mm and 91.25 mm, respectively. The fecundity varied from 3,451–32,465 eggs. Egg diameter distribution shows that spawning pattern of A. nalua was batch spawner. Keywords: Ambassis nalua, spawning season, sex ratio, reproduction

The DEVELOPMENT OF Elaeidobius kamerunicus FAUST POPULATION AFTER INTRODUCTION AND THE IMPROVEMENT OF OIL PALM FRUIT SET IN SERAM ISLAND, MOLLUCAS, INDONESIA

2016 ◽  
Vol 24 (1) ◽  
pp. 47-55
Author(s):  
Agus Eko Prasetyo ◽  
Agus Susanto
Keyword(s):  
Sex Ratio ◽  
Oil Palm ◽  
Fruit Set ◽  
Average Risk ◽  
Palm Fruit ◽  
Male And Female ◽  
Risk Of Death ◽  
North Sumatra ◽  
Female Flowers ◽  
Elaeidobius Kamerunicus

Elaeidobius kamerunicus is the main pollinating agent in oil palm plantations in Indonesia today. The development of oil palm plantations in new areas requires introduction of these insects, moreover the new areas are located on different islands. First introduction of Elaeidobius kamerunicus Faust had been done from North Sumatra to Seram Island on 23 September 2013. The introduction was performed on larva and pupa stadium in 4-5 days post anthesising of male inflorescences. The introduction of E. kamerunicus using plywood boxes has an average risk of death by 7.89% at 6 days delivery period. Observation before releasing of the weevils showed that this insect was not detected in both of oil palm male and female flowers and the oil palm fruit set was very low approximately 11.27%. For about 500 weevils/ha were released in Marnuhu estate and could be developed into 362,401 weevils/ha in 5 months with 97.86% of oil palm sex ratio. The oil palm fruit sets were increased after 1 and 2 months introduction, 53.70% and 75.56 %, respectively. The lower sex ratio of oil palm or the more availability of male inflorescences make growth of E. kamerunicus population became faster and the greater number of weevils that visiting anthesising of female flowers make the higher value of oil palm fruit set.

The DEVELOPMENT OF Elaeidobius kamerunicus FAUST POPULATION AFTER INTRODUCTION AND THE IMPROVEMENT OF OIL PALM FRUIT SET IN SERAM ISLAND, MOLLUCAS, INDONESIA

2018 ◽  
Vol 24 (1) ◽  
pp. 47-55
Author(s):  
Agus Eko Prasetyo ◽  
Agus Susanto
Keyword(s):  
Sex Ratio ◽  
Oil Palm ◽  
Fruit Set ◽  
Average Risk ◽  
Palm Fruit ◽  
Male And Female ◽  
Risk Of Death ◽  
North Sumatra ◽  
Female Flowers ◽  
Elaeidobius Kamerunicus

Elaeidobius kamerunicus is the main pollinating agent in oil palm plantations in Indonesia today. The development of oil palm plantations in new areas requires introduction of these insects, moreover the new areas are located on different islands. First introduction of Elaeidobius kamerunicus Faust had been done from North Sumatra to Seram Island on 23 September 2013. The introduction was performed on larva and pupa stadium in 4-5 days post anthesising of male inflorescences. The introduction of E. kamerunicus using plywood boxes has an average risk of death by 7.89% at 6 days delivery period. Observation before releasing of the weevils showed that this insect was not detected in both of oil palm male and female flowers and the oil palm fruit set was very low approximately 11.27%. For about 500 weevils/ha were released in Marnuhu estate and could be developed into 362,401 weevils/ha in 5 months with 97.86% of oil palm sex ratio. The oil palm fruit sets were increased after 1 and 2 months introduction, 53.70% and 75.56 %, respectively. The lower sex ratio of oil palm or the more availability of male inflorescences make growth of E. kamerunicus population became faster and the greater number of weevils that visiting anthesising of female flowers make the higher value of oil palm fruit set.

Sperm Competition and the Dynamics of X Chromosome Drive: Stability and Extinction

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1721-1731 ◽  
Author(s):  
Jesse E Taylor ◽  
John Jaenike
Keyword(s):  
Sex Ratio ◽  
Sperm Competition ◽  
X Chromosome ◽  
Sex Chromosome ◽  
Basin Of Attraction ◽  
Male Mating ◽  
Male And Female ◽  
Mating Rate ◽  
Female Mating ◽  
Balanced Polymorphism

AbstractSeveral empirical studies of sperm competition in populations polymorphic for a driving X chromosome have revealed that Sex-ratio males (those carrying a driving X) are at a disadvantage relative to Standard males. Because the frequency of the driving X chromosome determines the population-level sex ratio and thus alters male and female mating rates, the evolutionary consequences of sperm competition for sex chromosome meiotic drive are subtle. As the SR allele increases in frequency, the ratio of females to males also increases, causing an increase in the male mating rate and a decrease in the female mating rate. While the former change may exacerbate the disadvantage of Sex-ratio males during sperm competition, the latter change decreases the incidence of sperm competition within the population. We analyze a model of the effects of sperm competition on a driving X chromosome and show that these opposing trends in male and female mating rates can result in two coexisting locally stable equilibria, one corresponding to a balanced polymorphism of the SR and ST alleles and the second to fixation of the ST allele. Stochastic fluctuations of either the population sex ratio or the SR frequency can then drive the population away from the balanced polymorphism and into the basin of attraction for the second equilibrium, resulting in fixation of the SR allele and extinction of the population.

Staying ‘stoked’: Surfing, ageing and post-youth identities

2017 ◽  
Vol 54 (4) ◽  
pp. 387-409 ◽  
Author(s):  
Belinda Wheaton
Keyword(s):  
Middle Age ◽  
Cultural Barriers ◽  
Physically Active ◽  
Men And Women ◽  
Male And Female ◽  
South West ◽  
Barriers And Challenges ◽  
Ways Of Being ◽  
Scholarly Attention ◽  
Equipment Performance

Surfing has consistently been framed as a youth focused, male-dominated sport and culture. Despite surfing’s ageing demographic, neither the ways in which age impacts on surfing identities and mobilities, nor older surfer’s experiences and subjectivities, has been given scholarly attention. In this paper, I discuss research exploring the experiences and identities of middle-aged and older recreational male and female surfers in the south and south-west of England. The research illustrates that participation in surfing as a sport and lifestyle remains highly significant for some men and women through middle-age and into retirement. I consider the cultural barriers and challenges in dealing with a loss in physical performance through ageing, such as adaptations to their equipment, performance, and style, and the implications for how individuals negotiate bodily capital, space and identity. Nonetheless, older surfers also embrace different ways of being a surfer which challenge some of the more exclusionary aspects of surfing identities. Theoretically the paper develops an intersectional approach to sporting identity that explicitly recognises and accounts for the contribution of age to social identity. The research also contributes to the growing literature on physically active ‘post-youth’ leisure lifestyles, illustrating how shifting definitions of ageing have given ‘rise to new expectations, priorities and understandings’ of sporting lifestyles amongst those in middle age, and beyond.

scholarly journals KOMPOSISI UKURAN, PERBANDINGAN JENIS KELAMIN, DAN TINGKAT KEMATANGAN GONAD IKAN TODAK BERPARUH PENDEK (Tetrapturus angustirostris) DI SAMUDERAHINDIA

2017 ◽  
Vol 3 (2) ◽  
pp. 123
Author(s):  
Dian Novianto ◽  
Budi Nugraha ◽  
Andi Bahtiar
Keyword(s):  
Indian Ocean ◽  
Sex Ratio ◽  
Size Composition ◽  
Maturity Stage ◽  
Chi Square ◽  
Male And Female ◽  
Level Ii ◽  
Chi Square Test ◽  
The Indian Ocean ◽  
Tuna Longline

Ikan todak berparuh pendek atau ikan tumbuk atau shortbill spearfish (Tetrapturus angustirostris) merupakan salah satu hasil tangkapan sampingan rawai tuna. Informasi mengenai ikan todak berparuh pendek seperti komposisi ukuran, perbandingan kelamin, dan tingkat kematangan gonadsangat terbatas. Tulisan ini bertujuan untuk menyajikan data dan informasi mengenai aspek biologi ikan todak berparuh pendek yang merupakan hasil tangkapan sampingan dari rawai tuna yang beroperasi di Samudera Hindia. Penelitian ini dilakukan pada bulan September sampai Desember 2008 di perairan Samudera Hindia. Hasil penelitian menunjukan bahwa ikan todak berparuh pendek memiliki kisaran panjang tubuh 135-175 cmLJFL dan modus pada kisaran 155-165 cmLJFL.Perbandingan jenis kelamin ikan jantan dan betina 1:13,5, berdasarkan atas hasil uji chi-square menunjukan bahwa rasio ikan jantan dan betina pada periode penelitian ini tidak seimbang. Pada bulan September ikan todak berparuh pendek betina didominansi oleh tingkat kematangan gonad IIsebesar 66,7%, bulan Oktober oleh tingkat kematangan gonad V sebesar 46,2%, bulan Nopember oleh tingkat kematangan gonad II sebesar 53,3%, sedangkan pada bulan Desember oleh tingkat kematangan gonad III sebesar 42,9%. Pada bulan Nopember sampai Desember terlihat bahwa tingkat kematangan gonad V mulai berkurang, hal ini menunjukan bahwa pada bulan Nopember sampai Desember diduga banyak ikan todak berparuh pendek betina yang sudah memijah. Shortbill Spearfish (Tetrapturus angustirostris) is one of bycatch of tuna longline. Information about shortbill spearfish on the size composition, sex ratio, and maturity stage is still very limited. The objective this paper is to present the data and information about shortbill spearfish which is a bycatch of tuna longline that operated in the Indian Ocean. Research was conducted during September until December 2008 in Indian Ocean. The results showed that the shortbill spearfish have body length about 135-175 cmLJFL and modes in 155-165 cmLJFL. Sex ratio of the male and female was 1:13.5. Based on chi-square test showed that the ratio of male and female in the period of the study was not balanced. In September, the female stage maturity was dominated by level II of 66.7%, October by level V of 46.2%, November by level II of 53.3%, and December by level III of 42.9%. During November until December showed that the maturity stage of level V was decreased, this shows that in this time the female of shortbill spearfish was spawned.

scholarly journals Hubungan panjang bobot dan faktor kondisi ikan wader bintik dua Barbodes binotatus (Valenciennes, 1842) di Sungai Barambai Samarinda Kalimantan

2019 ◽  
Vol 18 (2) ◽  
pp. 87 ◽  
Author(s):  
. Jusmaldi ◽  
Nova Hariani
Keyword(s):  
Sex Ratio ◽  
Condition Factor ◽  
Mean Value ◽  
Male And Female ◽  
Weight Relationship ◽  
Total Length ◽  
East Kalimantan ◽  
Fish Samples

Biology of the spotted barb Barbodes binotatus (Valenciennes, 1842) in Barambai River, east Kalimantan is unknown. This study aimed to analyses sizes of fish, sex ratio, length-weight relationship and condition factor of the spotted barb. A total of 347 fish samples were collected by several gears in Barambai River from August to October 2017. The results of this research showed that the total length of the fish ranged from 45.67 to 146.01 mm and weight ranged from 1.27-43.34 g. The sex ratio of male and female were 1:1.12. The length-weight equations for males was W = 1x10-5 L3.063, W = 8x10-6L3.108 for females, and W = 9 x 10-6 L3.091 for both sexes. The condition factor (K) for the spotted barb was ranged between 0.826 – 2.214 with mean value of 1.163.  AbstrakBiologi ikan wader bintik dua Barbodes binotatus (Valenciennes, 1842) di Sungai Barambai, Kalimantan Timur belum diketahui. Penelitian ini bertujuan menganalisis ukuran ikan, nisbah kelamin, hubungan panjang bobot, dan faktor kon-disi. Total 347 sampel ikan dikumpulkan dengan menggunakan berbagai alat tangkap di Sungai Barambai dari bulan Agustus sampai Oktober 2017. Hasil penelitian menunjukkan bahwa panjang total ikan berkisar dari 45,67 sampai 146,01 mm dan bobot tubuh berkisar 1,27- 43,34 gram. Nisbah kelamin jantan dan betina 1: 1,12. Model hubungan panjang bobot ikan jantan W = 1x10-5 L3,063, ikan betina W = 8x10-6L3,108,dan keseluruhan jenis ikan W =  9 x 10-6  L3,091. Faktor kondisi (K) ikanwader bintik dua berkisar antara 0,826 - 2,214 dan rata-rata 1,163. 

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