scholarly journals The sex ratio in farmed American mink (<i>Neovison</i> <i>vison</i>)

2018 ◽  
Vol 61 (3) ◽  
pp. 359-363
Author(s):  
Lidia Felska-Błaszczyk ◽  
Natalia Ławrów ◽  
Bogdan Lasota ◽  
Beata Seremak ◽  
Katarzyna Pęzińska-Kijak ◽  
...  
Keyword(s):  
Sex Ratio ◽  
American Mink ◽  
Male Offspring ◽  
Time Interval ◽  
Gestation Length ◽  
Northern Poland ◽  
Mating Interval ◽  
Mating Time

Abstract. The aim of the study was to analyse the sex ratio of American mink litters in relation to dam's age, gestation length, and time interval between the first and second mating. The observations were carried out on a mink farm located in northern Poland. The analysis involved litters of 207 females, aged 1 (n=107) and 2 years (n=100), which successfully raised all the born kits. The sex of the offspring was identified on weaning. The kits were assigned to groups according to their dam's gestation length, mating date, and first-to-second mating interval. It was found that female kits quantitatively predominated over male offspring. Longer pregnancies, delayed mating time, and greater interval between the first and second mating was accompanied by a higher number of female births in relation to male births.

scholarly journals Reproductive potential and nesting effects of Osmia rufa (syn. bicornis) female (Hymenoptera: Megachilidae)

2016 ◽  
Vol 60 (1) ◽  
pp. 75-86 ◽  
Author(s):  
Karol Giejdasz ◽  
Monika Fliszkiewicz ◽  
Andrea Bednárová ◽  
Natraj Krishnan
Keyword(s):  
Sex Ratio ◽  
Reproductive Potential ◽  
Female Offspring ◽  
Male Offspring ◽  
Nesting Behavior ◽  
Solitary Bee ◽  
Male And Female ◽  
Individual Female ◽  
The Family ◽  
Number Of Cells

Abstract The red mason bee Osmia rufa is a solitary bee belonging to the family Megachilidae, and is prone to nest in aggregations. Each female builds a nest separately in pre-existing cavities such as holes in wood and walls or empty plant stems. This is done by successively setting the cells in a linear series. In this study, we elucidate the nesting behavior and the reproductive potential of a single O. rufa female. The reproductive potential of nesting females was evaluated after the offspring finished development. We observed that an individual female may colonize up to five nest tubes and build 5-34 cells in them (16 on an average). During the nesting time the number of cells decreased with the sequence of nest tubes colonized by one female, which built a maximum of 11 cells in the first occupied nest and 5 cells in the last (fifth nest). Our observations indicated that 40% of nesting females colonized one nest tube as compared to 7% colonizing five nest tubes. Furthermore, in subsequent nest tubes the number of cells with freshly emerged females gradually decreased which was the reverse with males. Thus, the sex ratio (proportion of male and female offspring) may change during the nesting period. The female offspring predominated in the first two nesting tubes, while in the subsequent three tubes male offspring dominated. We also cataloged different causes of reduction in abundance of offspring in O. rufa females such as parasitization or problem associated with moulting.

Sex ratio manipulation and decreased growth of male offspring of undernourished golden hamsters (Mesocricetus auratus)

1986 ◽  
Vol 18 (4) ◽  
pp. 241-249 ◽  
Author(s):  
Jay B. Labov ◽  
U. William Huck ◽  
Prabha Vaswani ◽  
Robert D. Lisk
Keyword(s):  
Sex Ratio ◽  
Mesocricetus Auratus ◽  
Male Offspring ◽  
Golden Hamsters

Trophectoderm grade significantly affects the sex-ratio imbalance in favor of male offspring

2013 ◽  
Vol 100 (3) ◽  
pp. S463
Author(s):  
T. Habara ◽  
S. Terada ◽  
N. Yoshioka ◽  
N. Hayashi
Keyword(s):  
Sex Ratio ◽  
Male Offspring ◽  
Sex Ratio Imbalance

Chromosomes and sex ratio of the collared lemming, Dicrostonyx richardsoni

1986 ◽  
Vol 64 (1) ◽  
pp. 12-15 ◽  
Author(s):  
Jay R. Malcolm ◽  
Ronald J. Brooks ◽  
James P. Bogart
Keyword(s):  
Sex Ratio ◽  
Chromosomal Polymorphism ◽  
Male Offspring ◽  
Binomial Probability ◽  
Centric Fission ◽  
Males And Females ◽  
Dicrostonyx Torquatus

The chromosomes of 18 laboratory-born Dicrostonyx richardsoni (= D. groenlandicus richardsoni) were examined. Eight females had 2n = 44 and two large metacentric chromosomes, three females and two males had 2n = 43 and three large metacentrics, and two females and three males had 2n = 42 and four large metacentrics. The observed chromosomal polymorphism was explained as a Robertsonian transformation in which metacentrics underwent centric fission to form two telocentrics, or two telocentrics fused to form a metacentric. No chromosomal differences were observed between males and females that had the same number of large metacentrics. The laboratory sex ratio at weaning was 0.38:1 (363 males, 596 females). Observed and expected distributions of proportions of male offspring among dams were significantly different if dams were assumed to produce males with binomial probability 0.5, or with probability 0.38. There was qualitative support for three female types, each producing males with probability 0.50, 0.25, or 0.33, as has been hypothesized for Dicrostonyx torquatus from Asia.

scholarly journals Effect of exposure time of pregnant females guppies, Poecilia reticulata Peters, in 17a-methyltestosterone solution on sex ratio of their offsprings

2007 ◽  
Vol 1 (1) ◽  
pp. 47
Author(s):  
M. Zairin Junior ◽  
A. Yunianti ◽  
R.R.S.P.S. Dewi ◽  
Kusman Sumawidjaja
Keyword(s):  
Sex Ratio ◽  
Exposure Time ◽  
Treatment Duration ◽  
Poecilia Reticulata ◽  
Female Offspring ◽  
Control Group ◽  
Time Interval ◽  
Water Flea ◽  
Pregnant Females ◽  
Males And Females

<p>ABSTRACT</p><p>This experiment was carried out to study the effect of female broodstocks immersion in 17amethyltestosterone (MT) solution on sex ratio of their offspring, Three-months old males and females were paired to mate in aquaria for four days.  Broodstocks were fed with frozen blood worm and water flea 2-3 tii-nes daily.  Twelve days after mating, female broodstock were treated by immersing in 2 mg/1 MT solution for 0. 6, 12, 24 and 48 hours.  Birthed guppy babies were collected and reared separately from their parents.  During the rearing period, the babies were fed with artemia nauplius and silkworm until identification for male and female.  Percentage of female offspring in control group were higher than those of male.  Exposure of pregnant females to MT solution for 0, 6, 12, 24, and 48 hours resulted in 42, 1'/o, 51%, 84,6%, 1 00%, dan 100% of males offspring, respectively.  The best result was obtained from 24 hours treatment.  Longer treatment duration tend to shorten time interval between treatment and birth. Key words :  Guppy, 17(x-methyltestosterone, exposure time, broodstock immersion, sex ratio   ABSTRAK Penefitian ini bertuiuan untuk mengetahui pengaruh lama waktu perendaman induk di dalam larutan hormon 17a-metiltestosteron (MT) terhadap nisbah kelamin ikan gapi.  Induk Ikan gapi berumur tiga bulan dikawinkan berpasangan di dalam akuarium selama empat hari Induk diberi pakan cuk merah beku dan kutu air dengan frekuensi 2-3 kali sehari.  Dua belas hari setelah masa perkawinan, induk betina diberi perlakuan berupa perendaman di dalam larutan MT 2 mg/1 selama 0 (kontrol), 6, 12, 24, dan 48 jam.  Anak-anak ikan gapi yang baru lahir dipelihara terpisah dari induknya.  Selama masa pemeliharaan, anak ikan gapi diberi pakan nauplius artemia dan cacing rambut.  Pemeliharaan berlangsung sampai jenis kelamin anak ikan gapi dapat diidentifikasi.  Persentase anak ikan gapi betina pada semua ulangan kontrol lebih tinggi daripada .iantan dengan perbandingan persentase rata-rata 57,9%: 42,1%.  Adapun pada lama waktu perendaman 0, 6, 12, 24, dan 48 jam, menghasilkan persentase anak ikan gapi berfenotip jantan berturut-turut sebesar 42,1%, 51%, 84,6%, 100%, dan 100%.  Lama waktu perendaman terbaik adalah 24 jam.  Selain itu terdapat kecenderungan bahwa semakin lama waktu perendaman semakin cepat kelahirannya. Kata kunci :  Ikan gapi, 17ot-metiltestosteron, lama perendaman, perendaman induk, nisbah kelamin</p>

scholarly journals Maternal Lineage of Warmblood Mares Contributes to Variation of Gestation Length and Bias of Foal Sex Ratio

PLoS ONE ◽  
2015 ◽  
Vol 10 (10) ◽  
pp. e0139358 ◽  
Author(s):  
J. Kuhl ◽  
K. F. Stock ◽  
M. Wulf ◽  
C. Aurich
Keyword(s):  
Sex Ratio ◽  
Gestation Length ◽  
Maternal Lineage

scholarly journals ANALISA ASPEK REPRODUKSI IKAN TOMAN (Channa micropeltes) DI SUNGAI BELIDA KABUPATEN MUARA ENIM

2020 ◽  
Vol 8 (1) ◽  
pp. 12-21
Author(s):  
Danang Yonarta ◽  
Yulisman Yulisman ◽  
Riswandi Riswandi
Keyword(s):  
Sex Ratio ◽  
Time Interval ◽  
Maturity Level ◽  
Female Fish ◽  
Natural Conditions ◽  
Male And Female ◽  
Gonad Maturity ◽  
Fish Resources ◽  
Gonadal Maturity ◽  
Abundant Population

Management of snakehead fish resources in swamp waters need to be done to anticipate a decline in stock in the waters. At this time the area where snakehead fish still have an abundant population is in southern sumatera, precisely in the Belida River, Muara Enim Regency. Until now there has been no information regarding the reproductive aspects of snakehead fish, their location and spawning season. The purpose of this study was to obtain information about the reproductive aspect of snakehead fish which includes sex ratio, gonad maturity level. Gonad maturity index and egg fecundity. The research was conducted in September-December 2019. The location was determined based on the natural conditions of the Belida River and human activities. Fish sampels were caught using experimental gill nets with ½ mash net size. Sampling of fish is done every 4 months with a time interval of once a month. The resuls of study in the male and female fish ratio 1,6:1. This ratio consisted of 109 fish (62,3%) and 66 female fish (37,7%). Gonadal maturity indeks  for male snakehead fish ranged from 0,21 to 0,86, while female snakehead fish ranged from 1,18 to 2,30. snakehead fish egg fecundity were 24.786 eggs with a diameter of 2,20 – 2,51

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