Patterns Of Reproductive Activity Research Articles

Variation in body size and reproductive characteristics among chromosomal races of the Sceloporus grammicus complex in México

Abstract Populations and chromosomal races of a species often show variation in life-history characteristics due to phylogeny and environmental factors. We analysed variation in snout–vent length (SVL) and reproductive variables, such as minimum SVL at sexual maturity, litter size and embryo volume in females of the Sceloporus grammicus lizard complex, which includes seven chromosomal races as well as hybrid zones among different combinations of races (F5, F5 + 6, potential but unverified F5 + 6, F6, FM1, FM2, FM2 × F5 hybrid zone, FM3, LS and unverified SGG). The SGG, F5 and LS females were larger than F6 and FM3 females. Females with non-vitellogenic follicles and vitellogenic follicles were smaller than females with embryos. The SVL of females containing embryos varied among chromosomal races, the largest being the same as indicated above, but the smallest was the FM2 × F5 hybrid zone. Litter size was similar among chromosomal races (5.8 embryos), while embryo volumes varied among them. Two patterns of reproductive activity were found: seasonal and continuous reproduction. Our results showed the influence of environmental factors of each locality, which supports the ecological hypothesis. The use of chromosomal races did not reveal a significant phylogenetic effect, because allozyme and molecular data show only small pairwise genetic distances among the S. grammicus populations on the Mexican Plateau.

Reproductive strategies of a lizard community from an arid environment of Mexico

The goal of this study is to describe patterns of reproductive activity and associated characteristics in a lizard community from an arid environment in the southern Chihuahuan Desert region of Mexico. Results of this study showed variation in snout–vent length (SVL) in adults female and male among 18 species. A similar pattern occurred in body mass of males and females, which varied mainly among species and not substantially between sexes. Mean clutch/litter size and egg/embryo mass and volume varied among species, and egg/embryo mass and volume were positively correlated with female SVL. Oviparous species were larger in SVL than viviparous species; however, SVL in females, clutch/litter size and egg/embryo volume were similar between oviparous and viviparous species, but the oviductal mass of oviparous species was larger than in viviparous species. Clutch/litter size and oviductal mass were correlated with female SVL in both oviparous and viviparous species. This relationship was similar for egg/embryo volume in oviparous species, but not in viviparous species. Seven species showed a prolonged reproductive period, and five had short reproductive periods. The results of this study provide evidence of high diversity in reproductive strategies that have evolved among organisms that live in this environment.

Reproductive activity and morphometric assessment of three commercial species of sea cucumber (Echinodermata) from Karimunjawa National Park, Indonesia

Abstract. Mustagfirin, Wijayanti DP, Subagiyo. 2021. Reproductive activity and morphometric assessment of three commercial species of sea cucumber (Echinodermata) from Karimunjawa National Park, Indonesia. Biodiversitas 22: 3333-3341. Sea cucumbers are benthic animals that have economic value and play an important role in the environment. Exploitation on large scale to fulfill high market demand, caused overexploitation. The number of sea cucumbers in Karimunjawa decreased as a result of limited management. There is no study conducted on the commercial sea cucumbers (Holothuria edulis, Pearsonothuria graeffei, and Bohadschia vitensis) in Nyamuk Island, Karimunjawa. The objectives of the research were to determine the morphometric assessment and the reproductive cycle of the three species. The morphometric assessment of weight showed that the weight of H. edulis ranges 247.3-2539g, P. graeffei 415.3-428.1g, and B. vitiensis 672.4-678.1g, respectively. The first maturity size of gutted body weight (GWB50) for H. edulis was 127.84g, P. graeffei 357.61g, and B. vitiensis 279.34g. The gonad somatic index (GSI) range 13.60-15.60% for H. edulis, 14.75-12.25% for P. graeffei and 10.83-14.57% for B. vitiensis. The result of gonad somatic index with a value above 10% means that it has entered the spawning phase. The above data indicated that the three commercial species spawned monthly, during new moon. It is likely that the spawning peak occurred when the temperature was increased. However, the pattern of reproductive activity in this study was limited at Nyamuk Island. Future studies are needed to observe whether there is a correlation between the increasing water temperature and the reproductive activity of the three sea cucumbers.

Reproductive activity patterns of four species of Cinnamomum in Purwodadi Botanic Garden

The aims of this study were to know flowering and fruiting pattern of the four Cinnamomum and their response in relation to seasonal change in rainfall, temperature and air humidity in Purwodadi Botanic Garden. The vegetative and reproductive activities were observed once per week based on the abundance of leaves, flowers and fruits using a scoring method from 0-4, for 6-8 years of observations. The rainfall per month, temperature, and humidity were simultaneously recorded. Data were analysed by Principal Component Analyses to determine the microclimate variables that have correlation to the reproductive activity patterns of all four species. Most species started flower budding during Juni – August, except C. burmanii which produced flowers 2-3 times per year in small quantity. Flowering of C. burmanii showed positively correlations with rainfall intensity, while flowering the other three species did not relate to microclimate in PBG. Six dry months preceding a long dry season in 2015 caused C. burmanii did not produce flowers and fruits.

Behavioral and morphological contrasts on the reproduction of two prolonged breeders of the genus Physalaemus (Anura: Leptodactylidae).

The reproduction is one of the main events in the life of an organism, and anurans stand out among vertebrates because of the diversity of their reproductive strategies. We studied the reproduction of two syntopic species, Physalaemus aff. albonotatus and P. santafecinus, and comparatively described their reproductive activity pattern, advertisement calls, calling sites, daily calling activity, amplexus behavior, foam nests, and microhabitats in foam nests. In regards to the reproductive activity pattern, both species were defined as prolonged breeders. However, P. santafecinus exhibited a behavior like explosive breeders: it had a faster reproductive response against rains than P. aff. albonotatus. The calling activity was restricted exclusively to night hours in P. santafecinus, whereas P. aff. albonotatus called during both night and day. The advertisement calls of both species showed a rich harmonic structure, and were characterized by a bimodal harmonic dominance. The species differed significantly in microhabitat calling sites, foam nests, and microhabitats in foam nests. Namely, P. santafecinus frequently called and constructed its nests in sites more exposed than those of P. aff. albonotatus. The general differences in reproductive behaviors observed between the species principally agree with their different reproductive activity patterns.

Demography and Condition of Brown Lemmings (Lemmus trimucronatus) During Cyclic Density Fluctuations Near Barrow, Alaska

We analyzed data collected from 19 428 necropsied brown lemmings (Lemmus trimucronatus) collected over a period of 22 years near Barrow, Alaska. Here we report on seasonal and cyclic patterns in reproductive activity of females and males, population structure, adult body size, condition (weight per unit length and body fat), and wounding. We also provide the first detailed information on these characteristics at low population densities. The seasonal pattern of reproduction included short summers (about 2.5 months) with intense reproduction, long winters (about 6.5 months) with moderate reproduction, and virtual cessation of breeding during the short springs and autumns (1.5 months each). Overall sex ratios appeared equal, but the proportion of males decreased during summer. The proportion of immature lemmings increased in late summer and autumn after intense summer breeding, then declined in winter. Adult body weight and condition (weight per unit length) peaked in summer when the food supply also peaked, but body fat, though still minimal, peaked in winter. The greatest incidence of wounding occurred in males, but wounding increased in both sexes during early summer, the period of most intense breeding. As reported previously for arvicoline rodents, a longer summer reproductive season occurred during the low and increase phases, but no change in litter size occurred during the cycle. Contrary to earlier reports, a much lower frequency of pregnancy occurred during the high phase, but later reproductive maturation during the high phase received little support. The sex ratio generally changed little during the course of a population cycle, but the proportion of females did decline during springs when the population increased to high densities. We found a greater proportion of adults during the high and decreasing phases, reflecting the reduced reproduction during those phases. Higher body weights and better condition of adults occurred during high densities. Wounding (fresh scars from bites) also peaked during years with high densities, though only for adult males and non-reproductive females. Overall, it appeared that nutrition strongly influenced seasonal changes in reproduction, population structure, and body condition; predation affected both seasonal and cyclic changes in population structure and survival; and that nutrition, and perhaps social strife, caused cyclic changes in reproduction, survival, and body size.

Reproductive dynamics of Lycengraulis grossidens (Clupeiformes: Engraulidae) and Platanichthys platana (Clupeiformes: Clupeidae) in a subtropical coastal lagoon.

We evaluated the reproductive dynamics of two fish species, Lycengraulis grossidens and Platanichthys platana, in a subtropical freshwater coastal lagoon (Peri Lagoon) in Brazil. Samples were collected from nine sites every two months from June 2008 to April 2012. Different fishing methods were used to capture larvae, juveniles, and adults. Limnological variables were obtained using multiparameter probe. More females than males were collected of both fish species and the chi-square test (χ2) was used to confirm that the sex ratio was female-biased. Large numbers of maturing and mature fishes were observed in almost every sampling month. The gonadosomatic index (GSI) of L. grossidens was the highest in August, October, and December for females and in October for males, and no significant difference was found across years. The GSI of P. platana showed no significant difference across months for either sex; however, significant differences were recorded in year three (June 2010-April 2011) and year four (June 2011-April 2012) for females and in year three (June 2010-April 2011) for males. For both species, GSI was negatively correlated with temperature and water level. L. grossidens larvae were more abundant in October 2010, showing a positive correlation with water transparency, whereas P. platana larvae were more abundant in June 2011, showing a positive correlation with water transparency and negative correlation with temperature and precipitation. Both species were represented by different stages, including larvae, which confirm that these species reproduce in Peri Lagoon. Reproduction was more pronounced in autumn and winter; however, reproductive activity was evident throughout the sampling period. In conclusion, our results show that abiotic factors strongly influence the temporal pattern of reproductive activity and larval assemblages of both L. grossidens and P. platana in Peri Lagoon, Brazil.

Spatial and temporal patterns of toadfish and black drum chorusing activity in the South Atlantic Bight

Many fish species produce sounds as a part of their reproductive behavior. Using passive acoustic recording approaches, these sounds can be used to document temporal and spatial patterns of reproductive activity of fish populations. We conducted an 11-month passive acoustic survey at three different locations off the coasts of Georgia (40 km north of Grays Reef National Marine Sanctuary) and North Carolina (Onslow Bay) to understand the spawning phenology of two species of acoustically active fishes: black drum (Pogonias cromis) and toadfish (Opsanus sp.). Due to the depth of the recording locations, we could not confirm whether the toadfish calls were produced by O. tau, or another Opsanus species. Both taxa have readily identifiable, distinct sounds. Chorusing sounds from both species were detected at all three Georgia sites and at two of the three North Carolina locations; chorusing duration of both species was greater in Georgia. The onset and duration of chorusing activity for both species was correlated with water temperature. The abundance of calls of these two species from field recordings further demonstrates the value of long-term passive acoustic surveys for understanding the reproductive seasonality of acoustically active fish species.

Seasonal and continuous spermatogenesis in the viviparous lizard Sceloporus grammicus, a study of two populations in contrasting environments from the Central Mexican Plateau

The annual histological changes of the seminiferous tubules and anterior testicular ducts were described for the viviparous lizard, Sceloporus grammicus, in two populations inhabiting contrasting environments; relating the reproductive activity of males with temperature, rainfall and photoperiod for each population. Adult males were collected monthly in Zacualtipán and Tizayuca, Hidalgo state, Mexico. Testes and anterior testicular ducts were removed and fixed in formalin, dehydrated in alcohol, embedded in paraffin, sectioned at 5μm and stained using hematoxylin-eosin. In the Zacualtipán population, the results revealed strong annual variations in stages of the germ cells, and diameter and height of the epithelia of seminiferous tubules, ductuli efferentes and ductus epididymis. In the Tizayuca population, the histological observations of the testis and anterior testicular ducts demonstrated spermiogenesis and spermiation throughout the year, an unusual pattern of reproductive activity, which had not been described previously in any populations of this species. The observed spermatogenesis patterns are not explained by a single environmental factor; but by the local set of environmental cues. In both populations, during spermatogenesis a single population of germ cells developed synchronously, followed by one massive spermiation event, which is characteristic of reptilian species. Our observations show differences between the two populations studied, which might be indicative of plasticity in response to local environmental conditions.

Oogenesis and ovarian histology in two populations of the viviparous lizardSceloporus grammicus(Squamata: Phrynosomatidae) from the central Mexican Plateau

The annual histological changes in ovarian morphology (oogenesis, follicular atresia, and corpus luteum) are described for the Mexican lizard Sceloporus grammicus, in two populations that inhabit contrasting environments (vegetation categories, climate, precipitation, and temperature) from Hidalgo State, Mexico. Two germinal beds were situated on the dorsal surface of each ovary of this species. In both the populations, oogenesis involves two major processes: previtellogenesis and vitellogenesis. The histological changes during previtellogenesis are similar to those for other reptilian sauropsids, whereas vitellogenesis differs and the features of this last process are described for the first time. In early previtellogenesis, primary oocytes have fibrillar chromosomes and the ooplasm stains slightly. The primordial follicles are surrounded by a granulosa composed of cuboidal follicular cells. During late previtellogenesis, the oocyte had an eccentric nucleus with lamp-brush chromosomes and multiple nucleoli. The granulosa becomes multilayered and polymorphic, containing three cell types: small, intermediate, and pyriform. The zona pellucida was homogeneous and clearly observed. In early vitellogenesis, the oocyte showed several small acidophilic granules distributed in the center and the periphery of the oocyte. As vitellogenesis progresses, the yolk platelets move toward the central area of the oocyte and they fuse to form acidophilic and homogeneous yolk. Lipid droplets were distributed irregularly in the ooplasm of the oocyte. In Zacualtipán, the results revealed a strong seasonal reproductive activity. Females had vitellogenic follicles from July to September, and pregnant females were founded from September to March. In Tizayuca, the results showed an unusual pattern of reproductive activity. Females with vitellogenic follicles and pregnant females were found throughout the year, indicating continuous reproduction. We suggest that the observed differences in reproductive activity from these populations indicate adaptative fine tuning in response to local environmental conditions. These results contribute to the knowledge of variation in vitellogenesis and reproductive strategies of this species and among spiny lizards overall.

[Reproductive ecology of Geobatrachus walkeri (Anura: Strabomantidae)].

Geobatrachus walkeri is a frog that belongs to a monotypic genus and is endemic to the Sierra Nevada de Santa Marta, Colombia. The species inhabits different microhabitats between 2 000 to 3 500m altitude, including the leaf litter of a pine plantation. To understand its reproductive ecology, we conducted eight frog samplings, covering the rainy and dry seasons, and two habitat types (secondary native forest and pine plantation) during 2010-2011. For this study, we also included data obtained from five previous similar samplings undertaken during 2008-2009. The pine leaf litter was the main microhabitat where frogs were found; we heard choruses of six-ten calling males during all sampled months, and observed the frogs having diurnal and nocturnal activity. Regardless of the year of study, the population consisted of neonates recruited several times of the year, a large number of juveniles with a wide range of body sizes, and fewer adults with a narrower range of body size. The histological analyses of the gonads showed that the size at maturity was near 18mm SVL for males and females, and those adult males and females were reproductive active during all sampling months, suggesting a continuous reproductive activity pattern. However, during the dry season, the seminiferous tubules showed a drastically diminished spermatic epithelium although containing abundant luminal spermatozoa, which suggest a reduction in the sperm production at the end of this season. Similarly, frogs of all age categories were significantly more abundant during the early dry season, whereas were significantly less abundant with the advancement of the dryness suggesting that the intensity of the dry season could temporally stop the activity and reproduction of this population.

Brooding in a temperate zone land snail: seasonal and regional patterns

The goal of this study is to assess if the reproductive strategy of a brooding land snail shifts along a climatic gradient. We focused on the following traits: timing and length of the reproductive season, brood size, ontogenetic dynamics of embryos, and reproductive mode (viviparity versus egg-laying). We dissected the central European door snail Alinda biplicata, collected monthly from eight populations covering the oceaniccontinental climatic gradient within the species’ distribution range. Forty percent of the 1706 dissected individuals were brooding. The species displayed a spring-summer reproductive activity pattern: intrauterine brooding was recorded between March and September; first embryos of a developmental stage that equals that of live-born neonates appeared in late April. Brooding started approximately when the mean daily temperature of a month exceeds ca. 5°C, thus the ontogenetic development of embryos is advancing earlier in populations under the influence of mild oceanic climate, and later in the eastern, more continental part of the range, or in submontane localities. A range-wide synchrony in reproduction occurred in May, when average temperatures and precipitation display a high rangewide similarity. The mean number of intrauterine eggs decreased between spring and summer in all populations (April: 10.9 ± 2.9; September: 6.4 ± 2.4), suggesting a gradual release of neonates which are not immediately replaced in uteri by new eggs. Snails from areas with long frosty winters do not invest much in a second reproductive period in late summer. Embryos of advanced embryonic stage were found in the reproductive tract of individuals from each population, thus we refute the hypothesis that A. biplicata switches its reproductive strategy towards oviparity under the influence of oceanic climate.

Patrón reproductivo y talla media de madurez sexual de hembras de la langosta <i>Panulirus gracilis</i> (Decapoda: Palinuridae) en Playa Lagarto, Guanacaste, Costa Rica

La langosta Panulirus gracilis es importante como recurso pesquero de las comunidades costeras en el Pacífico Norte de Costa Rica. Debido a la importancia de actualizar el conocimiento relacionado con el patrón reproductivo de esta especie, se analizaron 357 especímenes de langostas P. gracilis hembras capturados mediante el buceo con compresor y el buceo a pulmón durante noviembre de 2007 a octubre del 2008 en Playa Lagarto. Se examinó la composición de las tallas por estrato de profundidad, el patrón mensual de la actividad reproductiva (IAR) asociado al aumento relativo de la temperatura superficial del océano, y además se determinó la talla media de madurez sexual utilizando Modelos Lineales Generalizados. Los cuatro estados fisiológicos de madurez sexual mostraron que las hembras sin masa espermatófora y no ovígeras, presentaron las menores tallas con una media de 62.3mm de longitud cefalotoráxica (LC). Se observaron características de madurez sexual a partir de tallas muy bajas que van desde 30 a 50mm de LC, encontrándose la menor hembra ovígera reportada para esta especie de 35.8mm de LC y el mayor porcentaje de hembras maduras entre 70 y 80mm de LC. Los porcentajes del IAR se mantuvieron por encima del 50% durante el año, con excepción de los meses de octubre y enero. Además, se observó un aumento en el IAR que inició a partir de abril y continuó hasta agosto asociado a un relativo aumento en la temperatura a partir del mes de marzo, sin embargo esta relación no fue significativa (r2=0.49, p>0.05). No se descarta que la baja talla media de madurez sexual de 70.2mm de LC para P. gracilis en esta región sea causada por las prácticas de pesca. Se recomienda que se establezca una veda en la región de cinco meses (abril-agosto) con el fin de proteger la estacionalidad reproductiva de la especie y promover un mayor reclutamiento a las áreas de pesca.

The Interaction Between Photoperiod and Nutrition and Its Effects on Seasonal Rhythms of Reproduction in the Ewe1

In sheep, the seasonal patterns of reproductive activity are driven primarily by the annual photoperiodic cycle, but can also respond to other environmental factors, such as nutrition, yet little is known about the mechanisms underlying this interaction. This study was designed to define the interaction between photoperiodic and nutritional cues on seasonal patterns of ovarian activity, and to determine if there is a central interaction between these cues. Groups of Ile-de-France ewes were maintained in two nutritional states (restricted and well fed) under a simulated annual photoperiod of 8-16 h of light per day over two breeding seasons. At the end of the first breeding season, half of the animals of each group were ovariectomized (OVX) and fitted subcutaneously with estradiol implants. Low nutritional status shortened the season of ovarian activity, determined from the pattern of progesterone concentrations, by modifying the timing of seasonal transitions between periods of ovarian activity and anestrus. The same results were observed for the seasonal rhythm of neuroendocrine activity, assessed in the OVX ewes, from the pattern of luteinizing hormone concentrations. These results were then confirmed for neuroendocrine activity induced by a photoperiodic treatment. We conclude that nutrition centrally modulates the interpretation of photoperiod to affect seasonal reproductive transitions. The mechanisms of this interaction are discussed in the paper.

Control of Carapa guianensis phenology and seed production at multiple scales: a five-year study exploring the influences of tree attributes, habitat heterogeneity and climate cues

Abstract:During 5 y, we monitored reproductive activity and seed production of Carapa guianensis in two forest types to test the hypothesis that seed production is influenced by multiple factors across scales (regional climatic cues, local habitat heterogeneity and individual tree attributes). Variability in seed production was moderate at the population (CVp = 1.25) and individual level (xCVi = 1.24). A mixed model with a Poisson regression revealed that seed production was explained by variables at all scales. Total seed production was significantly higher in occasionally inundated forests. Diameter at breast height, dbh2, crown cross-sectional area, liana load, density, dry-season rainfall and mean maximum temperature were also significant in explaining seed production variation. Seed production increased with dbh until 40–50 cm, then decreased. Liana load demonstrated a negative relationship with seed production, but only in terra firme forests. Climatic cues (rainfall and temperature parameters) were central to setting overall patterns in reproductive activity and seemed to best explain why years with high seed production were consistent across the two forest types (habitats) examined. Dry-season rainfall was positively correlated with seed production.

Temporal and Spatial Patterns of Reproductive Activity inRhinella hoogmoedi(Anura: Bufonidae) from a Tropical Rainforest in Northeastern Brazil, with the Description of It's Advertisement Call

The study of ecological and behavioral aspects of anuran reproduction is fundamental for the understanding of the evolution of life history traits. In this study we present the temporal and spatial patterns of reproductive activity in Rhinella hoogmoedi, as well as the description of its advertisement call, in a population from a remnant of tropical rainforest in Northeastern Brazil. Calling activity began before the start of the rainy season and lasted from November to April; vocalization activity was not correlated with the amount of rainfall. Reproductive males called on a variety of substrates close to or in permanent or temporary water bodies, during both day and night. Male behavior at high and low densities, calling sites occupancy and reproductive period indicate an unusual explosive breeding pattern for the species. Rhinella hoogmoedi presented a multi-pulsed call, composed of pulse group calls, similar to Rhinella paraguayensis, Rhinella castaneotica, Rhinella martyi, populations of Rhinella gr. margaritifera from Bolivia, Rhinella margaritifera from French Guyana, and Rhinella gr. margaritifera from Cusco, Peru. Acoustic parameters such as call duration, number of pulse groups per call, number of calls per minute, note duration, number of notes per minute, pulse rate, dominant frequency, and amplitude modulation types of call, were good parameters to discriminate among the species of the Rhinella margaritifera group, as in the members of the Bufonidae family. New descriptions of complete advertisement calls and molecular studies will help elucidate taxonomic, biogeographic, and phylogenic patterns for this complex of species.

Distribuição temporal e diversidade de modos reprodutivos de anfíbios anuros no Parque Nacional das Emas e entorno, Estado de Goiás, Brasil

As comunidades de anfíbios anuros, principalmente de regiões tropicais, são influenciadas diretamente pelas condições ambientais, as quais desempenham um papel importante na estruturação e regulação das comunidades. Esse estudo teve como objetivo determinar a diversidade de modos reprodutivos, a temporada de vocalização e testar a correlação das variáveis climáticas sobre a riqueza, a abundância dos anuros adultos e dos girinos e sobre a atividade de vocalização dos machos em 12 corpos d'água localizados no interior e entorno do Parque Nacional das Emas, sudoeste do estado de Goiás, Brasil. Foram realizadas 16 amostragens entre dezembro de 2005 e março de 2008. Um total de 25 espécies de cinco famílias foram registradas: Bufonidae (uma espécie), Hylidae (nove espécies), Leptodactylidae (oito espécies), Leiuperidae (seis espécies) e Microhylidae (uma espécie). Quatro padrões de atividade reprodutiva foram reconhecidos entre as espécies: contínuo, intermediário, prolongado e explosivo. A riqueza de anuros adultos, a abundância e atividade de vocalização dos machos foram positivamente relacionadas com a temperatura do ar, umidade e precipitação. A riqueza de girinos foi positivamente relacionada com a precipitação e com a temperatura da água, mas não houve relação da abundância de girinos com nenhum dos descritores climáticos. Foram registrados seis modos reprodutivos: 56% das espécies apresentaram modos reprodutivos aquáticos generalizados (modo 1 e 4), e 44% depositam os ovos em ninhos de espuma (modos 11, 13, 30 e 32). As espécies registradas no presente estudo apresentaram predominância de modos reprodutivos generalizados e padrão reprodutivo tipicamente associado ao período quente e chuvoso, como esperado para regiões tropicais sazonais. Entretanto, a segregação temporal entre grupos de espécies dentro do período chuvoso parece facilitar a coexistência de espécies generalistas típicas de áreas abertas e/ou antrópicas.

Monitoring reproduction in the critically endangered marsupial, Gilbert’s potoroo ( Potorous gilbertii): Preliminary analysis of faecal oestradiol-17β, cortisol and progestagens

Gilbert’s potoroo ( Potorous gilbertii) was rediscovered in 1994 after having been presumed extinct for 120 years. Estimates indicate fewer than 40 individuals remain at Two Peoples Bay Nature Reserve on the south coast of Western Australia although a translocated population of approximately 20 animals has recently been established on nearby Bald Island. A captive breeding facility has been established adjacent to the mainland population but few young have been produced (8 since 1995). Faecal levels of oestradiol-17β (E 2) were monitored over a 2-year period in an effort to determine cyclic reproductive activity, and faecal cortisol levels were also monitored to gauge whether chronic stress may be a factor limiting breeding in captivity. Faecal steroids were monitored in six captive females, and four captive male potoroos, and four wild females. The only captive births recorded after 1998 were one in August 1999 and one in February 2001, both to the same female. Peaks in E 2 concentration, up to 10 ng g −1 of dried faecal mass were measured and results to date suggest the main breeding period to be November–December based on elevated E 2 levels at this time. Clear patterns of reproductive activity in the captive females, however, were not evident. Analysis of epithelial cell counts from urinogenital swabs and faecal E 2 and progestagen (PM) levels from a single female kept at the Perth Zoo, suggest that Gilbert’s potoroo has an oestrous cycle of approximately 39 days. Faecal cortisol levels in captive females were significantly lower than those in wild-caught individuals and thus there is no indication that elevated cortisol levels per se inhibited reproduction in captive females.

Effects of season and feeding level on reproductive activity and semen quality in Payoya buck goats

The aim of this study was to determine if there is a seasonal pattern of reproductive activity in male Payoya goats and if this seasonality can be modulated by a higher level of nutrition. For a period of 16 months, 10 adult bucks were divided into two experimental groups that differed in their feeding level. The high nutrition group (H, n = 5) received 1.6 times their maintenance food requirements. The control nutrition group (C, n = 5) received a diet that supported 1.1 times their maintenance requirements. Body weight and testosterone concentrations were determined weekly, and testicular weight was determined every 2 weeks. Sexual behaviour and semen characteristics were determined monthly. Feeding level did not affect the onset or the end of the reproductive activity as measured by testosterone concentrations, with high testosterone concentrations between July and November. Ejaculation latency was positively influenced by feeding level: 43.2 ± 2.2 s vs. 61.6 ± 3.2 s for H and C group, respectively ( P < 0.001). The percentage of males that ejaculated or that were sexually active was higher in the H group ( P < 0.01). No differences between feeding levels were observed in the different semen characteristics studied. However, major differences between months were observed for all studied variables. These results lead us to conclude that Payoya bucks exhibit large seasonal variation in their reproductive activity. Higher feeding level allowed a better sexual behaviour in bucks in late spring, when male effect is used on the local livestock to breed females.

Annual characteristics of estrous activity in wool and hair ewe lambs under subtropical conditions

The increased emphasis placed on lamb production in Brazil points to the need for a better knowledge of the annual pattern of reproductive activity in ewe lambs. This study evaluates the annual estrous activity pattern of hair and wool ewe lambs raised in southeast Brazil. Estrous characteristics were recorded for 12 months in ten Santa Inês and 21 Romney Marsh and Suffolk ewe lambs. Santa Inês ewe lambs exhibited a greater length of the normal estrous cycle (14 to 19 days) than Romney Marsh and Suffolk ewe lambs (17.0 ± 0.1 days vs. 16.5 ± 0.2 and 15.9 ± 0.2 days). All the ewe lambs presented a greater number of periods of estrus per animal per month for single estrous cycles (up to 26 days) during autumn and winter. During spring and summer there was a reduction of this number but this decline varied according to the breed. For Santa Inês ewe lambs the reduction was only significant in the summer. For wool ewe lambs the reduction was significant in both seasons but was more accentuated for Romney Marsh. The Romney Marsh ewe lambs had a more restricted breeding season than Suffolk and both presented optimal estrus activity in autumn and winter. Santa Inês ewe lambs had a continuous distribution of estrous cycles along the year, although presenting a reduction in the number of estrous periods in the summer. The ewe lambs of three breeds presented characteristics of sexual immaturity, like irregular estrous cycles and silent ovulations.