The reproductive biology of the two-banded sea bream (Diplodus vulgaris) from the SW Coast of Portugal.

Journal of Applied Ichthyology 16(3): 110-116. DOI:10.1046/j.1439-0426.2000.00232.x

Volltext

Abstract:

The study of the reproduction of Diplodus vulgaris (Geoff.) as part of a base-line study of the fishery resources of the south-west coast of Portugal, was based on the analysis of the spawning season, gonad maturation, size at maturity, fecundity and hermaphroditism. The spawning season is relatively long, from December to March, with peaks in January and February. No significant differences were found either in the sex ratio (M : F = 1.01) over the year or by size. The size at first maturity (L50) for all sexes and undetermined individuals combined was 18.33 cm total length (TL), with no significant differences between males and females. The estimated L50 is considerably greater than the minimum legal size in Portugal of 15.0 cm. Mean absolute fecundity (Fa) was 131 127 oocytes, ranging from 31 523 to 250 608. The relationship between absolute fecundity and total length (TL) (Fa = 25 398 TL – 484 426) and somatic weight (SW) (Fa = 878.8SW – 71 416) was of the linear type. The mean number of oocytes per gram of somatic weight was 526, ranging from 194 to 887. The reproductive strategy of this species is characterized by a rudimentary hermaphroditism with possible protandry, as evidenced by the existence of individuals in sexual transition.

gonçalves-biblio

https://www.researchgate.net/publication/230327695_The_reproductive_biology_of_the_two-banded_sea_bream_Diplodus_vulgaris_from_the_SW_Coast_of_Portugal

Reproduction in the round-eared elephant shrew (Macroscelides proboscideus) in the southern Karoo, South Africa.

Journal of Zology 240(2): 233-243. https://doi.org/10.1111/j.1469-7998.1996.tb05282.x

Abstract:

Reproduction in round-eared elephant shrews occurred throughout the year. Male round-eared elephant shrews were spermatogenically active, with spermatozoa stored in the cauda epididymes, throughout the year. Pregnant females occurred in all months except March and May and there was a decline in the occurrence of pregnancies during early winter (March-July). This tendency towards seasonality of pregnancies was mirrored by the appearance of juveniles, with 77% of all young animals caught between September and February. Bone calcium concentrations were significantly lower during the dry winter than during summer. From October onwards (the beginning of the wet season), bone calcium concentrations increased, reaching high levels in December which were maintained until April. This increase in bone calcium concentrations coincided with the rainy season and with an increase in the intake of herbage, and during this period 60% of all pregnancies occurred. We conclude that the ability of the round-eared elephant shrew to vary its diet may allow some individuals to breed throughout the year. The reduction in the occurrence of pregnancies in early winter probably ensures that few births occur when bone calcium concentrations are low.

bernard-biblio

Breeding Biology of Vanellus chilensis (AVES: Charadriidae) in a Peri-urban Area of Southern Brazil.

Revista de Ciéncia Ambientais 13(3): (ISSN 1981-8858). http://dx.doi.org/10.18316/rca.v13i.6070

Abstract:

The neotropical species Vanellus chilensis, known as Southern Lapwing, is found in grassland environments, in rural and urban open areas. e species is considered a social Bird, which aggregates in pairs or small groups during the breeding period, in austral spring and summer. During the reproductive period, the cooperative breeding behavior is common among individuals of the species, when a non-breeding individual, called "helper", assists the breeding pair in parental care activities. We monitored a total of 11 social breeding unities of V. chilensis between august 2014 and january 2015 in the Universidade do Vale do Rio dos Sinos campus, in São Leopoldo, Rio Grande do Sul. We conducted nest observations, by evaluating the breeding success of individuals regarding eggs and chick's loss, with and without helpers' presence, as well as behavioral aspects. We recorded the laying of 65 eggs, of which 10.7% achieved breeding success, regarding the number of viable chicks. In this study, helpers' presence in the nests did not influence the breeding success of individuals, thus, dismissing the hypothesis that helpers' assistance improves breeding success of the species. Our findings contribute to the knowledge on the breeding biology of V. chilensis in peri-urban areas.

haeberlin-biblio

Notes on Nest and Chicks of the Guianan Red Cotinga (Phoenicircus carnifex) in Amazonas, Brazil.

The Wilson Journal of Ornithology 127(3):521–523.

Abstract:

The Guianan Red Cotinga (Phoenicircus carnifex) is a poorly known member of the family Cotingidae, and information concerning its biology, ecology, and natural history are scarce. We provide the first description of the nest and young of the Guianan Red Cotinga and provide additional natural history data on its diet and habitat preferences.

gomes-biblio

Nicht invasive Bestimmungsmethoden von Steroidhormonen und deren Anwendung bei Geparden (Acinonyx jubatus) in europäischen Zoos.

Vet.med. Diss., FU Berlin.
Gutachter: Univ.-Prof. Dr. Heribert Hofer; Prof. Dr. Klaus Eulenberger; Univ.-Prof. Dr. Jörg Aschenbach
78 Seiten; Tabellen; Grafiken.

Volltext (PDF)

Zusammenfassung:

Die bisherigen Erfolge in der Züchtung von Geparden (Acinonyx jubatus) in menschlicher
Obhut sind bis heute nicht zufriedenstellend. Seit Jahrzehnten wird an den Ursachen dieser
Problematik geforscht. Bis vor kurzem ging man noch davon aus, dass der genetische
Flaschenhals, durch den die Population entstehungsgeschichtlich gegangen ist, maßgeblichen
Anteil an dem Phänomen hat. Untersuchungen im Freiland zeigten jedoch, dass freilebende
Geparde regelmäßig und problemlos reproduzieren, wenn sie in Ökosystemen leben, in denen
keine Löwen (Panthera leo) und Tüpfelhyänen (Crocuta crocuta) vorkommen, die ihre
Jungtiere töten. Davon unterscheiden sich die Populationen in den Zoos weltweit
entscheidend. Hier kommt es selten zu erfolgreichen Nachzuchten, obgleich Löwen und
Tüpfelhyänen als Mortalitätsursache der Jungtiere ausscheiden. Verschiedene Gründe
wurden hierfür untersucht. Unter anderem wurde vermutet, dass die unterschiedlichen
Lebenssituationen der Tiere im Freiland und in Zoos zu einer unterschiedlichen Belastung
führen, und somit die erhöhte Allostase („Stress“) in begrenzter und gemanagter Umgebung
zu einer schlechteren Reproduktion führt. Allerdings gelingt es einigen Einrichtungen immer
wieder verlässlich, mit Geparden Nachzuchterfolge zu erzielen. Auch wenn die
Stressbelastung in zoologischen Gärten höher als im Freiland sein sollte, ist zu erwarten dass
sich die erfolgreich züchtenden Haltungen in einem oder mehreren Faktoren von den nicht
erfolgreich züchtenden Haltungen unterscheiden.

Diese Dissertation wurde durchgeführt, um diese Faktoren zu ergründen und
gegebenenfalls Empfehlungen zur besseren Erhaltungszucht dieser bedrohten Tiere in Zoos
zu ermöglichen. Hauptaugenmerk lag auch in dieser Arbeit zuerst auf der Untersuchung der
allostatischen Belastung der Zootiere. Die Konzentration von Glukokortikoiden im Körper wird
gewöhnlich als ein Maß für den Stress bei Wirbeltieren verwendet. Blutabnahmen unter
Narkose führen allerdings binnen kürzester Zeit zu einer akuten Erhöhung dieser Hormone im
Blut, die keinen Rückschluss auf vorausgehende Werte mehr zulassen. Daher sollte die
Probennahme berührungsfrei erfolgen, um Handling-Effekte bei der Messung der
Glukokortikoid-Messwerte zu vermeiden. Hierzu eignet sich bei Katzen besonders der Kot, um
die Metabolite der Glukokortikoide zu messen. Bisher gab es keinen für Geparde validierten
Enzyme-Immunoassay (EIA), der die fäkalen Glukokortikoid-Metabolite (fGCM) messen
konnte und sie auch charakterisierte, sowie die Affinität des EIA bestimmte. Die vorhandenen
Radio-Immunoassays (RIA) werden auf Grund der Radioaktivität oft nur ungern eingesetzt.
Daher wurde in Kapitel 2 ein neuer EIA für Geparde entwickelt und technisch wie biologisch
validiert und charakterisiert. Der EIA dokumentierte erfolgreich eine erhöhte Konzentration
von fGCM nach der experimentellen Zuführung von adrenocorticotropen Hormon (ACTH) bei
einem männlichen und einem weiblichen Gepard. Diese experimentelle Zuführung von
Hormonen mit dem Nachweis eines erwarteten Ergebnisses wird als „Hormonchallenge“
bezeichnet und ist die hierfür allgemein akzeptierte Form einer biologischen Validierung.
ACTH führt über eine Aktivierung der Nebennierenrinde zu einem schnellen Anstieg von
Glukokortikoiden im Blut. Dieser Anstieg ist mit Verzögerung von etwa einem Tag dann auch
im Kot nachweisbar.

Glukokortikoide (wie z.B. Cortisol) gehören zu den Steroidhormonen. Da sich Cortisol-
Metabolite nur unwesentlich von anderen Steroidhormon-Metaboliten (wie z.B von
Testosteron) unterscheiden, war eine eindeutige Abgrenzung zu den fGCM im Kot wichtig.
Kapitel 3 beschreibt einen zweiten entwickelten EIA, der Testosteron-Metabolite im Kot
detektiert. Dieser unterstreicht nicht nur die gut trennbare Messung von Testosteron-
Metaboliten zu anderen Steroidhormon-Metaboliten, sondern könnte in Zukunft auch
Aussagen über die reproduktive Aktivität männlicher Tiere berührungsfrei erlauben. Auch der
Testosteronassay wurde mit Hormonchallenges biologisch validiert. So wurde ein erhöhter
Testosteronanstieg nach der Injektion von Gonadotropinreleasinghormon (GnRH)
nachgewiesen. GnRH bewirkt in der Hypophyse eine Freisetzung von Gonadotropinen (Follikel
stimulierendes Hormon (FSH), Luteinisierndes Hormon (LH)), die wiederum auf die
Geschlechtsorgane wirken. LH bewirkt beim männlichen Säuger durch Aktivierung der Leydig-
Zellen der Hoden u.a. einem Anstieg von Testosteron im Blut. Dieser war im Kot nachweisbar.
Kapitel 4 verglich fGCM von reproduzierenden und nicht reproduzierenden weiblichen
Geparden, um zu untersuchen, ob die beiden Gruppen unterschiedliche Stresswerte
aufwiesen, was nicht der Fall war. Es war zudem bereits bekannt, dass Schwierigkeiten in der
Reproduktion in menschlicher Obhut auch nicht durch die geringe genetische Variabilität der
Geparde verursacht wurde und es keine(n) endogene(n) jahreszeitlichen Umweltsignale
(Zeitgeber) gibt, der/die die Reproduktion auslöst/en. Daher wurden die Vorhersagen zweier
weiterer Hypothesen untersucht, um zu verstehen, welche Faktoren einen Einfluss auf den
Fortpflanzungserfolg von Gepardenweibchen haben könnten. Dies waren die Hypothesen (1)
fehlende Fortpflanzung aufgrund der reproduktiven Unterdrückung durch Artgenossen, 2)
fehlende Fortpflanzung aufgrund der beschleunigten Alterung der inneren Geschlechtsorgane
(ARA = asymmetric reproductive aging) bei Weibchen, die sich nicht in jungen Jahren
fortpflanzen. Die lebensgeschichtlichen Daten bezüglich der reproduzierenden und nicht
reproduzierenden weiblichen Geparde in fünf zoologischen Gärten in Europa sind mit den
Vorhersagen beider Hypothesen kompatibel.

Die Diskussion der gesamten Doktorarbeit und der neuen Erkenntnisse behandelt
Kapitel 5. Darin werden auch Empfehlungen für die zoologischen Gärten und das europäische
Erhaltungszuchtprogramm (EEP) vorgestellt, damit in Zukunft die unbefriedigenden
Nachzuchterfolge dieser Spezies der Vergangenheit angehören.

ludwig-biblio

Notes on Reproduction of the Zebra Shark, Stegostoma fasciatum, in a Captive Environment.

In: SMITH, M. et al. (2004) The Elasmobranch Husbandry Manual: Captive Care of Sharks, Rays and their Relatives: 493-497. ISBN-13: 978-0-86727-152-3

Abstract:

A pair of zebra sharks (Stegostoma fasciatum) successfully reproduced in the Shark Reef exhibit, Henry Doorly Zoo. Mating behavior was similar to that described for the nurse shark (Ginglymostoma cirratum) (Klimley, 1980; Carrier et al., 1994) and chain dogfish (Scyliorhinus retifer) (Castro et al., 1988). Between September 1998 and September 2000, 80 fertile eggs were laid. Mean incubation time was 152.5±26.5 days, newborns had a mean TL of 30.2±0.8 cm, and mean weight of 92.2±14.0 grams. Increased water temperature resulted in decreased incubation time (R2=0.887, n=6).

kunze-biblio

Virgin birth in a hammerhead shark.

Biol Lett. 2007 Aug 22; 3 (4): 425–427.
Published online 2007 May 22. doi: 10.1098/rsbl.2007.0189

Abstract:

Parthenogenesis has been documented in all major jawed vertebrate lineages except mammals and cartilaginous fishes (class Chondrichthyes: sharks, batoids and chimeras). Reports of captive female sharks giving birth despite being held in the extended absence of males have generally been ascribed to prior matings coupled with long-term sperm storage by the females. Here, we provide the first genetic evidence for chondrichthyan parthenogenesis, involving a hammerhead shark (Sphyrna tiburo). This finding also broadens the known occurrence of a specific type of asexual development (automictic parthenogenesis) among vertebrates, extending recently raised concerns about the potential negative effect of this type of facultative parthenogenesis on the genetic diversity of threatened vertebrate species.

chapman-biblio

Reproduction, Growth and Development in Captive Beluga (Delphinapterus leucas).

Zoo Biology 24 (1): 29-49.
https://doi.org/10.1002/zoo.20037

Abstract:

Recent success propagating captive beluga has resulted from combined efforts by North American zoos and aquariums to manage disparate collections as a single population. This success has provided a tremendous opportunity to increase our understanding of beluga reproductive biology. Blood samples were collected on a weekly to biweekly basis from 23 female and 12 male beluga, ranging in age from 2–15 years, for analysis of serum progesterone (P) and testosterone (T), respectively. Peri‐parturient observational data, including food intake, duration and signs of labor, and nursing patterns were collected from 15 days prepartum to 30 days postpartum during 21 births. Total body lengths and weights were collected from 10 captive‐born beluga. For female beluga, the mean (±SD) age, body length, and weight at first conceptions were 9.1±2.8 years, 318.0±9.1 cm, and 519±84 kg. Thirty‐five luteal phases and 13 conceptions were detected from January–June, and 70% of luteal phases and 80% conceptions occurred from March–May. The mean luteal phase and total estrous cycle lengths were 30.0±6.5 days and 48.0±4.6 days, respectively. For male beluga, the mean age that males sired their first calf was 13.3±2.6 years. Compared to younger males (<8 years of age, 0.95 ng/ml), levels of T secretion in older males (>8 years of age, 5.0 ng/ml) were elevated significantly only during the interval from January–April. Highest T concentrations (6.2±4.9 ng/ml) were recorded from January–March, whereas nadir concentrations (1.1±1.0 ng/ml) were detected from August–September. The mean gestation length was 475.0±20.4 days (n=9). For parturition, the mean time from the first appearance of fluke or rostrum to delivery, delivery to placental passage, and delivery to nursing were 4.4±2.9 hr, 7.6±1.8 hr, and 43±45 hr, respectively. All cows had decreased food intake on the day of delivery, with 44% having zero intake. Peak 24‐hr nursing activity occurred 3.9±2.7 days post‐partum. Growth (i.e., body weight and length) as a function of age were well described by the Gompertz model (r2=0.91, 0.93). Based on the model, growth in body weight and length were significantly greater in males compared to females. Predicted birth weight (88.9 kg) was similar for both sexes, however, and male calves were predicted to be shorter (154.3 cm) than female calves (160.7 cm). The results provide the first descriptions of captive beluga reproductive physiology, including endocrinology, peri‐parturient behavior, growth, and reproductive maturity. This knowledge is important for helping to maintain genetically diverse, self‐sustaining populations of captive beluga whales. Zoo Biol 24:29–49, 2005. © 2005 Wiley‐Liss, Inc.

robeck-biblio

Reproductive Biology of Boiga guangxiensis Wen, 1998 (Serpentes: Colubridae)

Asian Herpetological Research 2010, 1(1): 44-47
DOI: 10.3724/SP.J.1245.2010.00044

Abstract:

Up to now, the reproductive biology of most species of the genus Boiga is investigated very little. Important data on the reproductive biology of Boiga guangxiensis were received by us for the first time. The investigations were carried out in Viet Nam during expeditions and in the laboratories of Tula Exotarium in the period between 1998−2000.

The data on the feeding, egg size, incubation, size of hatchings, and juvenile colouration of this species are provided for the first time. In addition, the data on size and ratio of snout-vent length/tail length of this snake are provided based on the Vietnamese samples. Our researches demonstrated that B. guangxiensis is distinguished from most other species of the genus by a number of peculiarities of its reproductive biology. Also, morphological differences between Chinese and Vietnamese individuals of this species were noted.

One-sided ejaculation of echidna sperm bundles.

The American Naturalist 170:162-164. DOI: 10.1086/522847

Abstract:

We report for the first time an unusual ejaculatory mechanism in the short-beaked echidna in which each side of the bilaterally symmetrical, rosettelike glans penis is used alternately, with the other being shut down. This is unparalleled in mammals but is reminiscent of the use of hemipenes in squamate reptiles, providing further reproductive evidence of a sauropsidian lineage in the Monotremata. Further, we describe the occurrence of motile sperm bundles in ejaculated echidna semen and provide scanning electron micrographs of their morphology. Sperm bundling appears to confer increased sperm motility, which may provide the potential for sperm competition between males.