Reproductive biology

Several reproductive specializations are found within the elasmobranchs. All elasmobranchs fertilize internally and produce a relatively small number of large eggs. Elasmobranch fecundity generally ranges from one to two offspring produced a year up to a maximum of 300 in the whale shark (Compagno, 1990; Joung et al., 1996). Elasmobranch reproductive strategies include oviparity, aplacental viviparity and placental viviparity (Wourms, 1977). Oviparous species enclose eggs in an egg case and deposit them into the environment, where embryos develop external to the body of the mother . .Embryos remain in the egg case to develop for a period ranging from less than two months to over one year (Compagno, 1990). Viviparous species retain eggs within the uteri where the embryos develop. The yolk sac of placental viviparous species interdigitates with the uterine wall to form a placenta in which nutrients from the mother are transferred to the embryo. In most species the egg envelope is retained and incorporated into the uteroplacental complex (Hamlett, Wourms and Hudson, 1985). Gestation for viviparous species ranges from less than six months to greater than two years (Compagno, 1990). Viviparous species may have either lecithotrophic or matrotrophic development. Lecithotrophic development occurs when embryos derive their nutrition solely from yolk reserves and occurs in many aplacental viviparous species. Matrotrophic development occurs when embryos supplement the yolk reserves by obtaining maternally derived nutrients during gestation and also occurs in many aplacental species and all placental viviparous species (Wourms and Lombardi, 1992). The advantage of matrotrophy may be the increase in juvenile size at birth and therefore increased survivorship of young. Another important consideration in the evolution of elasmobranch reproductive strategies is the presence or absence of uterine compartments. Uterine compartments are formed in all species with placental development and some species with aplacental development and are believed to be an important step in the evolution of placental viviparity (Otake, 1990).https://scholarworks.wm.edu/vimsbooks/1026/thumbnail.jp

Nectaries and reproductive biology of croton sarcopetalus (euphorbiaceae)

Flower morphology, nectary structure, nectar chemical composition, breeding system, floral visitors and pollination were analysed in Croton sarcopetalus, a diclinous-monoecious shrub from Argentina. Male flowers have five receptacular nectaries, with no special vascular bundles, that consist of a uniserial epidermis with stomata subtended by a secretory parenchyma. Female flowers bear two different types of nectaries: inner (IN) and outer (ON) floral nectaries. IN, five in all, are structurally similar to the nectaries of male flowers. The five ON are vascularized, stalked, and composed of secretory, column-shaped epidermal cells without stomata subtended by secretory and ground parenchyma. In addition, ON act as post-floral nectaries secreting nectar during fruit ripening. Extrafloral nectaries (EFN) are located on petioles, stipules and leaf margins. Petiolar EFN are patelliform, stalked and anatomically similar to the ON of the female flower. Nectar sampled from all nectary types is hexose dominant, except for the ON of the female flower at the post-floral stage that is sucrose dominant. The species is self-compatible, but geitonogamous fertilization is rarely possible because male and female flowers are not usually open at the same time in the same individual, i.e. there is temporal dioecism. Flowers are visited by 22 insect species, wasps being the most important group of pollinators. No significant differences were found in fruit and seed set between natural and hand pollinated flowers. This pattern indicates that fruit production in this species is not pollen/pollinator limited and is mediated by a wide array of pollinators. © 2001 The Linnean Society of London.Fil: Freitas, Leandro. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Bernardello, Gabriel Luis Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Galetto, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Paoli, Adelita. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

5 Reproductive Biology

The reproductive potentiaI of animal species is a compound result of numerous behavioral and physiological characteristics, most of which can be considered species-typical. These include such things as the time required to attain reproductive maturity, the number of nesting or renesting attempts per year once maturity is attained, the number of eggs laid per breeding attempt, and the number of years adults may remain reproductively active. These traits place an upper limit on the reproductive potential of a species, which is never actually attained. Rather, the actual rate of increase will only approach the reproductive potential, being limited by such things as the incidence of nonbreeding; the mortality rates of adults; decreased hatching success resulting from infertility, predation, or nest abandonment; relative rearing success; incidence of renesting and clutch sizes of renests; and similar factors that affect the reproductive efficiency. The relative involvement of the male in protecting the nest or the young may also influence hatching or rearing success. Among those species in which the male does not participate in nesting behavior, the relative degree of monogamy, polygamy, or promiscuity may strongly influence the reproductive ecology and population genetics of the species. Although many of these considerations will be treated under the accounts of the individual species, a general comparison of the grouse and quail groups as a whole are worth considering here, to see if any general trends can be detected

Reproductive Biology of Kawakawa, Euthynnus Affinis (Cantor, 1849) in Eastern Indian Ocean

Tongkol komo (Euthynnus affinis) merupakan salah satu jenis ikan ekonomis penting bagi nelayan di Denpasar, Bali. Penelitian ini bertujuan untuk menganalisis biologi reproduksi ikan tongkol komo seperti tingkat kematangan gonad (TKG), indeks kematangan gonad (IKG) dan panjang proporsi matang gonad 50% (L50) dan 95% (L95) tongkol komo di Samudra Hindia Bagian Timur. Contoh ikan dikumpulkan dari hasil tangkapan nelayan yang didaratkan di Pangkalan Pendaratan Ikan (PPI) Kedonganan, Bali dari bulan Mei hingga September 2016. Jumlah contoh ikan yang dikumpulkan sebanyak 168 ekor, masing-masing diukur panjang cagak, bobot individu, bobot gonad dan penetapan TKG. Data yang diperoleh dianalisis untuk menentukan TKG, IKG dan proporsi matang gonad. Hasil penelitian diperoleh panjang cagak berkisar antara 26-55 cm dengan rata-rata 38 cm dan didominasi kelas panjang 28 cm. Tingkat kematangan gonad ikan didominasi oleh TKG III (38%), kemudian diikuti oleh TKG II (26%), TKG I (22%) dan TKG IV (14%). Rata-rata indeks kematangan gonad sebesar 0,558 dengan kisaran 0,009-5,075. Proporsi Panjang matang gonad 50% dan 95% berturut-turut adalah 48,4 cm dan 55,7 cm. Perlu dilakukan pengaturan penangkapan sehingga 50% ikan yang tertangkap sudah pernah memijah

Reproductive Biology Of Pokea Clam Batissa Violacea Var. Celebensis, Von Martens 1897 At Lasolo Estuary, Southeast Sulawesi

Pokea clam Batissa violacea var. celebensis von Martens 1897 that inhabits the substrates of some estuaries in Southeast Sulawesi has a tendency to have different reproductive pattern. The aim of this study was to determine the sex ratio, gonadal maturity stage (TKG), gonadal maturity index (IKG) and the size at first gonad maturity of pokea in Lasolo estuary, Southeast Sulawesi. Samples were randomly collected using a traditional fishing gear called tangge. Sex ratio, TKG, IKG, and the size at first gonad maturity were determined using standard methods and formulas and then analyzed using Chi Square, quantitative description and non-linear regression. The results showed that the number of males were higher than the numbers of females, ranging from 71.85-89.84% and 10.16-28.15%, respectively. Gonadal maturity development of male and female occured simultaneously. Early gonadal maturity stage began in January. Spawning occurs twice, beginning with maturity in April and spawning in May and then again maturity in July and spawning in July until October. IKG values of male and female were relatively the same ranging from 2.56-31.92. The males matured earlier than the females at size 1.95 cm and 2.15 cm, respectively

Reproductive Biology of Silurid Catfishes Ompok Miostoma (Vaillant 1902) in Mahakam River East Kalimantan

Biologi reproduksi ikan lais O. miostoma (Vaillant 1902)sebagai salah satu spesies endemik di Sungai Mahakam Kalimantan Timur belum pernah diketahui. Tujuan penelitian ini adalah menganalisisaspek reproduksi ikan laisberkaitan dengan Perubahan musimyang mencakupnisbah kelamin, musim pemijahan, lokasi pemijahan, ukuran kali pertama matang gonad, indeks kematangan gonad dan fekunditas.Total ikan contoh 1214 ekor telah dikumpulkan setiap bulan mulai dari bulan November 2013 sampai Oktober 2014di empat lokasi perairan Sungai Mahakam, menggunakan berbagai alat tangkap. Hasil penelitian menunjukkanukuran panjang total ikan berkisar dari 132,19-227,30 mm dan bobot berkisar dari 20,00-70,40 gram.Nisbah kelamin seluruh ikan jantan dan betina yang diamati 1 : 1,56, sedangkanpada tahap kematangan gonad 1:1,77. Musim pemijahan terjadi mulai dari bulan November sampai Januari dan puncak pemijahan pada bulan Desember. Lokasi pemijahan tertinggi ditemukan di rawa banjiran Danau Semayang. Ukuran ikan pertamamatang gonad pada jantan berkisar dari 191,05-202,60 mm dan betina berkisar dari 179,56-198,50 mm. Rata-rata indeks kematangan gonad (IKG) tertinggi ditemukan pada jantan dan betina berturut turut 0,32 dan 2,07 selama musim pemijahanpada bulan November dan menurun hingga terendah pada bulan Februari. Fekunditas total berkisar dari 2.648-12.495 butir telur per individu.Ada korelasi positif antara fekunditas dengan panjang total dan bobot ikan

Reproductive Biology of Pigs

This report describes aspects of sexual development and maturation, hormonal regulation in boars, hormones and puberty in gilts )including the environment and hormone treatment, estrous cycle, ovulation rate, conception rates, embryo survival, and litter size), pregnancy, lactation, and sows at weaning. In addition, genes that affect these developmental and reproductive processes are included

Reproductive biology of Sciaenid fish, Johnieops osseus (Day), from the South Kanara coast

Though some informalion is available regarding the breeding habits and early life histories of sciaenids'-s detailed studies on reproductive biology are lacking. The present paper deals with the reproductive biology of Johtlieops osseus, the dominant species of the sciaenids captured off South Kanara Coast