Increased male sex ratio among brachypterous progeny in Melittobia femorata, a sib-mating parasitoid wasp (Hymenoptera: Eulophidae)

Trichogramma wasps are tiny parasitoids of lepidopteran eggs, used extensively for biological control. They are often infected with the bacterial symbiont Wolbachia, which converts Trichogramma to an asexual mode of reproduction, whereby females develop from unfertilized eggs. However, this Wolbachia-induced parthenogenesis is not always complete, and previous studies have noted that infected females will produce occasional males in the lab. The conditions that reduce penetrance of the parthenogenesis phenotype are not well understood. We hypothesized that more ecologically relevant conditions of limited host access will sustain female-biased sex ratios. After restricting access to host eggs, we found a strong relationship between reproductive rate and sex ratio. By limiting reproduction to one hour a day, wasps could sustain up to 100% effective parthenogenesis for one week, with no significant impact on total fecundity. Reproductive output in the first 24-hours appears to be critical to the total sex ratio of the entire brood. Limiting oviposition in that period resulted in more effective parthenogenesis after one week, again without any significant impact on total fecundity. Our data suggest that this phenomenon may be due to the depletion of Wolbachia when oviposition occurs continuously, whereas Wolbachia titers may recover when offspring production is limited. In addition to the potential to improve mass rearing of Trichogramma for biological control, findings from this study help elucidate the context-dependent nature of a pervasive symbiotic relationship.

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Absence of complementary sex determination in Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae)

10.7287/peerj.preprints.27871 ◽

2019 ◽

Author(s):

Quan-quan Liu ◽

Jin-cheng Zhou ◽

Chen Zhang ◽

Qian-jin Dong ◽

Su-fang Ning ◽

...

Keyword(s):

Sex Ratio ◽

Sex Determination ◽

Brood Size ◽

Indirect Evidence ◽

Parasitoid Wasp ◽

Mass Rearing ◽

Diploid Male ◽

Diploid Males ◽

Offspring Sex Ratio ◽

Complementary Sex Determination

Over 60 species in Hymenoptera have been reported to possess a complementary sex determination (CSD) system. Under CSD, sex is determined by allelic complementation at one or several sex loci. But this mechanism is still uninvestigated in parasitoid wasp Trichogramma dendrolimi, one of the most important biocontrol agents widely used against Lepidopteran pests. We tested CSD in this species by conducting ten consecutive generations of inbreeding, to monitor both direct evidence (diploid male production) and indirect evidence (brood size, sex ratio, mortality). In total 475 males detected from this inbreeding regime, only one was determined as diploidy. The observed proportions of diploid male offspring significantly differed from expected values under CSD model involving up to ten independent loci, allowing us to safely reject CSD in T. dendrolimi. Meanwhile, the possibility of unviable diploid males was excluded by the absence of significant differences in brood size, offspring sex ratio and offspring mortality among different generations. Our study of sex determination in T. dendrolimi provides useful information for the mass rearing conditions in a biofactory and the quality improvement of this biocontrol agent. It also brings necessary background to further study of the sex determination in Trichogramma.

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APLIKASI TEPUNG TESTIS SAPI YANG MENGANDUNG rGH DALAM PAKAN BUATAN TERHADAP RASIO JENIS KELAMIN, PERTUMBUHAN DAN KELULUSHIDUPAN IKAN NILA (Oreochromis niloticus)

Pena Akuatika Jurnal Ilmiah Perikanan dan Kelautan ◽

10.31941/penaakuatika.v17i2.656 ◽

2018 ◽

Vol 17 (2) ◽

Author(s):

Rachmat Nurul Huda ◽

Titik Sulistiowati ◽

Tristiana Yuniarti

Keyword(s):

Growth Rate ◽

Survival Rate ◽

Sex Ratio ◽

Specific Growth Rate ◽

Oreochromis Niloticus ◽

Specific Growth ◽

Sex Reversal ◽

Average Weight ◽

Fish Feed ◽

Male Sex

ABSTRAKBudidaya ikan nila (Oreochromis niloticus) terus dikembangkan hingga saat ini. Berbagai teknologi dalam bidang perikanan telah diterapkan, salah satunya yaitu sex reversal dalam hal ini jantanisasi. Ikan nila jantan lebih cepat pertumbuhannya dari pada ikan nila betina sehingga dapat meningkatkan hasil produksi. Tujuan penelitian ini yaitu untuk mengetahui pengaruh pemberian tepung testis sapi dan dosis terbaik tepung testis sapi dalam pakan yang mengandung rGH terhadap rasio jenis kelamin, pertumbuhan dan kelulushidupan ikan nila. Bahan uji yang digunakan adalah larva ikan nila dengan stadia larva yang berumur 7 hari setelah lepas kuning telur dan memiliki bobot rata-rata 0,07 gram/ekor. Penelitian ini menggunakan metode eksperimental dengan Rancangan Acak Lengkap 4 perlakuan dan 3 kali ulangan. Perlakuan dalam penelitian ini yaitu dengan menambahkan tepung testis sapi dengan dosis pada perlakuan A (0%/kg pakan), perlakuan B (3%/kg pakan), perlakuan C (6%/kg pakan) dan, perlakuan D (9%/kg pakan). Pakan pada setiap perlakuan dalam penelitian ini telah ditambahkan rGH dengan dosis 2 mg/kg pakan. Data yang diamati meliputi rasio jenis kelamin, laju pertumbuhan spesifik (SGR), dan tingkat kelulushidupan (SR) ikan nila. Hasil penelitian menunjukan bahwa perlakuan C (6% tepung testis sapi/kg pakan) memberikan hasil terbaik dimana nilai rasio jenis kelamin jantan sebesar 74,44±5,09% dan laju pertumbuhan spesifik sebesar 9,48±0,10% bobot/hari. Kesimpulan yang diperoleh dalam penelitian ini yaitu adanya pengaruh nyata terhadap rasio jenis kelamin dan tingkat pertumbuhan spesifik, namun tidak berpengaruh nyata terhadap tingkat kelulushidupan ikan nila dengan pemberian dosis tepung testis sapi terbaik adalah 6% tepung testis sapi/kg pakan.Kata kunci: Sex reversal; Tepung testis sapi; Pertumbuhan, rGH; NilaABSTRACTTilapia fish (Oreochromis niloticus)cultivation still continue to be developed until nowdays. Many fisheries technology had been applied, and one of them is sex reversal which is masculinization. Male tilapia fish grows faster than the female one, so this can boost the produce of the fish. This research aims to know the effect of cow testicle flour addition and determine the best dosage on the fish feed which contains rGH towards the male-sex ratio, growth, and survival rate of tilapia fish. The material which used in this research was tilapia fish (O. niloticus) which under the larvae phase 7 days post the separated egg yolk which have average weight of 0,07 grams/each. This research used experimental methods with Completely Randomized Design of 4 treatments and 3 times of repetitions. The treatments in this research was addition of different dosage of bull testicle which treatment A (0%/kg fish feed),treatment B (3%/kg fish feed), treatment C (6%/kg fish feed) and, treatment D (9%/kg fish feed). The fish feed in every treatment had been added with 2mg rGH/kg fish feed. Data observation during this research were male-sex ratio, specific growth rate (SGR), and survival rate (SR) of tilapia fish. Results of the research showed that treatment C (6%/kg fish feed) gave the best result as male-sex ratio by 74,44±5,09% and specific growth rate by 9,48±0,10% weight/day. Conclusion obtained from this research was: there was different result towards the male-sex ratio and specific growth rate, but there was no difference between the treatments towards the survival rate, the best bull testicle flour dosage was 6%/kg fish feed. Keywords: Sex reversal, Bull testicle flour, Growth, rGH, Tilapia

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BIOLOGI REPRODUKSI IKAN BETOK (Anabas testudineus) DI PAPARAN BANJIRAN LUBUK LAMPAM,KABUPATEN OGAN KOMERING ILIR

BAWAL Widya Riset Perikanan Tangkap ◽

10.15578/bawal.6.3.2014.137-146 ◽

2015 ◽

Vol 6 (3) ◽

pp. 137

Author(s):

Eko Prianto ◽

Mohammad Mukhlis Kamal ◽

Ismudi Muchsin ◽

Endi Setiadi Kartamihardja

Keyword(s):

Sex Ratio ◽

Anabas Testudineus ◽

Commercial Fish ◽

Male And Female ◽

Climbing Perch ◽

Male Sex ◽

First Maturity ◽

Egg Diameter ◽

Floodplain Area ◽

Somatic Index

Ikan betok (Anabas testudineus) adalah salah satu jenis ikan ekonomis penting yang dihasilkan dari perairan paparan banjiran. Penelitian yang bertujuan untuk mengkaji beberapa aspek biologi reproduksi ikan betok di paparan banjiran Lubuk Lampam, Kabupaten Ogan Komering Ilir dilakukan pada bulan Nopember 2012-Oktober 2013. Sampel ikan ditangkap setiap bulanmenggunakan alat tangkap jaring dan bengkirai.Analisis data meliputi sebaran frekuensi ukuran panjang, nisbah kelamin, tingkat kematangan gonad, indeks kematangan gonad, ukuran pertamakali matang gonad, potensi reproduksi dan pola reproduksi. Jumlah sampel ikan betok yang diperoleh sebanyak 540 ekor, terdiri dari 187 ekor ikan jantan dan 353 ekor ikan betina, dengan kisaran panjang ikan betina antara 27-224 mm dan ikan jantan antara 48-243 mm. Rasio kelamin ikan jantan dan betina adalah 0,53 : 1. Tingkat kematangan gonad (TKG) ikan jantan dan betina yang paling banyak ditemui adalah TKG I dengan frekuensi tertinggi pada ukuran 116-132 mm dan 114-129 mmmasing-masing berjumlah 34 dan 33 ekor. Perkembangan tingkat kematangan gonad ikan betok dipengaruhi oleh perubahan tinggimuka air secara musiman. Indek kematangan gonad ikan jantan pada TKGIV berkisar 1,3-15,0%dan ikan betina berkisar antara 1,2 17,1%. Ukuran pertama kali matang gonad ikan betina adalah pada panjang total 160 mm dan ikan jantan pada panjang total 177 mm. Fekunditas ikan betok berkisar antara 224–182.736 butir dengan diameter telur berkisar antara 0,465-1,026 mmdengan pola pemijahan secara sebagian. Climbing perch, Anabas testudineus is a dominant commercial fish inhabit floodplain area of Lubuk Lampam, Ogan Komering Ilir Regency. A study aimed to investigate some aspects of the reproductive biology of climbing perch has been conducted at floodplain of Lubuk Lampam, Ogan Komering Ilir regency from November 2012 to October 2013. Fish sampling was conducted every month using nets and bamboo trap. The data analysis includes lenght frequency distribution, sex ratio, the gonado maturity, gonado somatic index, the size at first maturity, fecundity and reproductive patterns. Climbing perch sample amounted of 540 specimen compose of 187 males and 353 females, with the lenght frequency between 27-224 mm (female) and 48-243 mm (male). Sex ratio of the male and female of the climbing perch was 0,53 : 1. The gonado maturity of male and female are mostly at the first level with the highest frequency between 116-132 mm and 114-129 mm, equivalent to 34 and 33 specimen, respectively. The development of gonado maturity of climbing perch was influenced by seasonally of water level fluctuation. Gonado somatic index of maturity of male and female range 1.3-15.0% and 1.2 -17.1%, respectively. The size at the first maturity of the female was 160 mm lenght and of the male was 177 mm lenght. The fecundity ranges 224 to182,736 eggs with the egg diameter ranges 0.465-1.026 mm and the climbing perch was classified into partially spawner.

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Investigation of intersexual polled goats

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/65/1870 ◽

2015 ◽

pp. 11-15

Author(s):

Judit Bordán ◽

András Kovács ◽

Szilárd Bodó

Keyword(s):

Sex Ratio ◽

Mammalian Species ◽

Sex Reversal ◽

Ovary Development ◽

X Chromosomes ◽

Ovary Cells ◽

Male Sex ◽

Sox9 Gene ◽

Foxl2 Gene

The sex reversal may occur in all mammalian species, but is connected to a favourable trait – the polledness – only in the goat. Later abnormal sex ratio was noticed in these goat populations, in which a part of the phenotypically male individuals was sterile. These males have two X chromosomes. In goats the PIS (Polled Intersex Syndrome) mutation is responsible for the absence of horns in homozygous and heterozygous individuals. This same mutation causes a female-to-male sex reversal, but only in the homozygous polled genetic female goats. The PIS mutation inhibits the expression of the FOXL2 gene which is responsible for ovary development, and a protein encoded by this gene inhibits the activity of the Sox9 gene. The Sox9 gene stimulates the development of the cells of the testis. When the FOXL2 gene is inhibited, the Sox9 gene is activated and transforms the ovary cells into testis cells. In our article we briefly introduce the morphological and chromosome investigations of three intersex individuals we found.

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