Variation In Reproductive Parameters Research Articles

Reproductive Characteristics of the Northern Mole Vole at the Northeastern Periphery of Species Range

Animal populations living at the periphery of species range are characterized by increased natural mortality, which affects the pattern of population dynamics and reproductive potential of individuals. However, trends of variation in reproductive parameters along ecological gradients are as yet unclear. Analysis of age at maturity, timing of pregnancy, and rates of postnatal development in reproductive pairs of northern mole voles (Ellobius talpinus) kept under laboratory conditions has shown that the test parameters in a population living at the northeastern periphery of the species range (Novosibirsk oblast) are different from those in a population from the optimal zone of the range.

Annual variation in reproductive parameters and sexual behaviour of Saint Croix rams in a semi-desert region in Mexico

ABSTRACT The aim of this study was to determine the semen quality, sexual behaviour and testosterone (T) levels in Saint Croix rams under semi-desert climate conditions. Sixteen rams (70.6 ± 12.5 kg; 24.1 ± 0.3 months old) were randomly divided into a grazing group (GG, n = 8) and a supplemented group (supplemented individually with 1 kg.d−1 of concentrate (156 g CP.kg−1 DM and 2.5 Mcal EM.kg−1 DM). SG, n = 8). Each group grazed on buffel, grass. Every two weeks, semen was collected, and sexual behaviour traits were evaluated. SG rams had greater body weight (P < 0.0001) and greater semen quality than the GG rams. SG rams had greater values for reaction time and lateral approaches than GG rams (P < 0.0001). No interaction was found between treatment and month for T concentration (P < 0.05); the SG rams had greater values during most of the months, but GG rams had greater values during September. Month had a significant effect on T concentration (P < 0.05) with the highest values in autumn. It can be concluded that Saint Croix rams are able to adapt to adverse environmental conditions and that supplementary feed prior to the mating season improves ram sexual behaviour.

Seasonal and interannual changes in reproductive parameters and eggs biochemical composition of the fishery resource Pleuroncodes monodon (Decapoda: Munididae) from the Humboldt Current System

Environmental variables are key drivers of reproductive traits in marine organisms, which can have significant economic consequences in commercial species. Pleuroncodes monodon is an important resource of the industrial fisheries’ fleet of the Humboldt Current System. This species is subject to seasonal variations in pivotal variables such as temperature and food availability, as well as, climatic events. We herein analyse the variations in reproductive parameters and in the eggs’ biochemical profiles in relation to environmental conditions. Differences in all studied parameters were found between 2014 and 2015. In 2015, fecundity (measured as total number of eggs) and protein content were higher than 2014, but lipid content showed the opposite pattern. Seasonal and interannual variations were also observed in the energy content per egg; whilst the brood energy content did not show seasonal or interannual variation. This information is of utmost importance for integrative management of this commercial good as the data measures dynamic variations in the species populations. Currently, this squat lobster is overexploit and so far, no seasonal nor interannual variations have been considered in its management plan. The present study provides evidences that the female lobsters need different management strategies to maintain sustainable fisheries of Concepcion, Chile.

The influence of environmental variables in the reproductive performance of Macrobrachium amazonicum (Heller, 1862) (Caridea: Palaemonidae) females in a continental population.

Macrobrachium amazonicum is a commercially important freshwater prawn with a high degree of reproductive plasticity. The species is classified into two groups: coastal populations, with larger individuals exhibiting high fecundity and needing brackish water for larval development; and continental populations, with smaller specimens exhibiting low fecundities and completing metamorphosis in freshwater. The objective of this study was to investigate the influence of environmental factors in the fecundity, egg size and volume, and reproductive output in females of M. amazonicum from a continental population during a two-year period. We also compared our results with those obtained for other continental and coastal populations. Reproductive parameters differed markedly between continental and coastal populations in most cases. The continental population studied here, however, exhibited reproductive characteristics similar to those of coastal populations. The present study found a correlation between the reproductive parameters and the environmental variables analyzed. This result corroborates the hypothesis that wide variation in reproductive parameters in the geographical distribution of M. amazonicum is related to the environmental characteristics in which populations are inserted. We suggest that further studies could investigate the potential of continental populations for aquaculture, which could significantly reduce production costs.

Geographic variation in life‐history traits: factors shaping energy investment in reproduction in a highland dwelling rodent

AbstractVariation in life‐history traits is shaped by intrinsic and extrinsic factors. Climate influences the availability of energy and nutrients in the environment, and thus animals’ energy balance, their allocation of resources to reproduction and ultimately, fitness. Temperature is reported as a prevailing influence on animals’ investment in reproduction, and diverse hypotheses propose mechanisms by which it occurs. Central and external limits to energy acquisition have been traditionally assumed. Hence, digestive limitations, periods of low food availability or demanding cold conditions would restrict this input. However, under warm conditions endotherms also face the need to dissipate heat from metabolic processes. From this perspective, a high metabolic rate process, such as lactation, would be restricted under increasing ambient temperatures (Ta). Our research addresses the variation in reproductive parameters in Phyllotis xanthopygus, a rodent species broadly distributed in the west highlands and southern parts of South America. Across a pronounced elevation gradient in the central Andes Mountains we found that litter size is comparatively smaller in pregnant females collected at lower elevations. This is congruent with expectations from the heat dissipation limit hypothesis. To disentangle the role of temperature on this pattern, we bred individuals under two thermal treatments. We recorded no changes in the litter size, but pups’ body mass was lower at higher Ta during lactation, also in agreement with decreased metabolism. Offspring size and number are relevant to a species’ fitness. The evidence suggests that in P. xanthopygus these traits vary geographically and are shaped by Ta in the laboratory. A species that evolved in high altitudes, inhabits cold and temperate areas and is sensitive to Ta increases in the laboratory, appears as an excellent candidate to further explore the ecophysiology‐thermal landscape interface, crucial to develop accurate predictive models of biodiversity dynamics.

Assessment of Some Morphometric Parameters in Ram Sperm Correlated with the Collection Method

Abstract It is well known that assisted reproductive techniques are implemented and used worldwide in livestock production, having as aim to allow high genetic animals to produce more descendants in a shorter period of time than possible naturally. They have enabled animal breeders to optimize production and reproduction efficiency of their animals by improving selective traits and accelerating the genetic progress. Artificial insemination techniques in sheep increase the selection differential, being one of the main biotechnologies that are used extensively in the animal livestock. The present research has in view to assess the influence of collection techniques upon some morph metric parameters of the ram sperm. There were analyzed 10 native purebred and crossbred rams from different age category. The semen collection was made by artificial vagina and with the aid of electro ejaculator. At every semen collection, there were recorded the main morphologic features of sperm and also the primary morph metric head sperm indices: head length, head width, head area and head perimeter. The influence of the collection technique was in view along two years, studying the dynamics of the analyzed sperm indices through the computer image analysis. Descriptive statistics were performed on the recorded data to determine normality. Statistical analysis was performed as per standard statistical methods. The results reveal the fact that there were no morph metric differences between the two collection methods. The lack of significant differences indicated that other factors may affect the reproduction efficiency between the two methods. The study clearly demonstrates that there is a variation in reproductive parameters in the rams which could be studied at the molecular level to unveil any genomic markers associated with low fertility and/or infertility. The results obtained for this part of the overall study emphasizes further research to correlate morph metric traits of ram sperm with conception rate of ewes to determine whether morph metric traits need to be included in sperm quality tests for artificial inseminations.

Speciation and reduced hybrid female fertility in house mice.

In mammals, intrinsic postzygotic isolation has been well studied in males but has been less studied in females, despite the fact that female gametogenesis and pregnancy provide arenas for hybrid sterility or inviability that are absent in males. Here, we asked whether inviability or sterility is observed in female hybrids of Mus musculus domesticus and M. m. musculus, taxa which hybridize in nature and for which male sterility has been well characterized. We looked for parent-of-origin growth phenotypes by measuring adult body weights in F1 hybrids. We evaluated hybrid female fertility by crossing F1 females to a tester male and comparing multiple reproductive parameters between intrasubspecific controls and intersubspecific hybrids. Hybrid females showed no evidence of parent-of-origin overgrowth or undergrowth, providing no evidence for reduced viability. However, hybrid females had smaller litter sizes, reduced embryo survival, fewer ovulations, and fewer small follicles relative to controls. Significant variation in reproductive parameters was seen among different hybrid genotypes, suggesting that hybrid incompatibilities are polymorphic within subspecies. Differences in reproductive phenotypes in reciprocal genotypes were observed and are consistent with cyto-nuclear incompatibilities or incompatibilities involving genomic imprinting. These findings highlight the potential importance of reduced hybrid female fertility in the early stages of speciation.

Study Regarding Age-Related Morphometric Features of Buffalo Sperm

Semen production quality from reproduction males depends upon different factors such as:age, breed, collection method, environmental conditions. The present research was conducted to establish the influence of age upon the quantitative and qualitative indices of the native buffalo semen. There were analyzed 20 native buffalo males, from different age categories. At every semen collecting there were recorded the following morphologic and morphometric sperm indices: sperm volume, sperm concentration (x 106spz/ml), total number of sperm cells/ejaculate(x109), head length, head width, tail length, head area and shape factor.The influence of the age was made along two years, studying the dynamics of the sperm indices through the computer image analysis. Descripted statistics were performed on the recorded data to determine normality. Statistical analysis was performed as per standard statistical methods.The results revealed the fact that the best performances were recorded in bulls older than three years old. The study clearly demonstrates that there is a variation in reproductive parameters in the bovine bulls, which could be studied at the molecular level to unveil any genomic markers associated with low fertility and/or infertility. The males may be utilized to obtain semen by subjecting the young ones to training at an early age, thereby decreasing the initial age of semen donation.

Clutch‐size variation in Western Palaearctic secondary hole‐nesting passerine birds in relation to nest box design

Summary Secondary hole‐nesting birds that do not construct nest holes themselves and hence regularly breed in nest boxes constitute important model systems for field studies in many biological disciplines with hundreds of scientists and amateurs involved. Those research groups are spread over wide geographic areas that experience considerable variation in environmental conditions, and researchers provide nest boxes of varying designs that may inadvertently introduce spatial and temporal variation in reproductive parameters. We quantified the relationship between mean clutch size and nest box size and material after controlling for a range of environmental variables in four of the most widely used model species in the Western Palaearctic: great tit Parus major, blue tit Cyanistes caeruleus, pied flycatcher Ficedula hypoleuca and collared flycatcher F. albicollis from 365 populations and 79 610 clutches. Nest floor area and nest box material varied non‐randomly across latitudes and longitudes, showing that scientists did not adopt a random box design. Clutch size increased with nest floor area in great tits, but not in blue tits and flycatchers. Clutch size of blue tits was larger in wooden than in concrete nest boxes. These findings demonstrate that the size of nest boxes and material used to construct nest boxes can differentially affect clutch size in different species. The findings also suggest that the nest box design may affect not only focal species, but also indirectly other species through the effects of nest box design on productivity and therefore potentially population density and hence interspecific competition.

Different life-histories of native and invasiveNeogobius melanostomusand the possible role of phenotypic plasticity in the species’ invasion success

One of the most successful invasive fish species with negative impacts is round goby Neogobius melanostomus that has spread from its original Ponto-Caspian area to west and central Europe and even to North America. Previous studies focused on invasive fishes have revealed that these species have the capability to generate forms with life-history traits that differ between native and non-native populations. As a contribution to explain their invasion success, the theory of alternative ontogenies and invasive potential has been developed. The main aim of the present study was to test the hypothesis derived from this theory, which predicts that females of the non-native population of N. melanostomus (from Slovakia) will have significantly smaller oocytes, higher fecundity and smaller body size at maturity than those of the native population (from Bulgaria). All the three quantitative parameters of life-history traits examined in this study were found to be consistent with the predictions tested. Variations in reproductive parameters observed in non-native N. melanostomus demonstrate the species’ phenotypic plasticity, which appears to be an important attribute that helps potential invaders to establish new populations in unknown environments. However, further experimental studies are necessary to verify this theory by testing hypotheses derived from it.

Temporal variation in reproductive characteristics of an introduced and abundant island population of koalas

Reproductive characteristics of a wildlife population are typically sensitive to changes in environmental conditions and intrinsic factors. Knowledge of these relationships is critical for understanding population dynamics and effective long-term management of a population. We examined temporal variation in reproductive parameters of an abundant, genetically compromised, and high-density population of koalas (Phascolarctos cinereus) on Kangaroo Island, South Australia, over 3 breeding seasons spanning 9 years: November–May of 1997–1998, 2005–2006, and 2006–2007. Timing of the breeding season was consistent between years, but fecundity, sex ratio of young, and the percentage of independent females (those not accompanying a lactating female) , 6 kg varied. Fecundity was lower than in other island populations, suggesting that the quality and distribution of food resources or inbreeding may be impacting the Kangaroo Island population. We did not test for Chlamydophila (synonym 5 Chlamydia), and clinical signs of this disease were not reported for any of the koalas in this study. However, historical evidence of Chlamydophila-infected koalas on Kangaroo Island exists, and the potential impact of this disease on fecundity warrants further investigation. DOI: 10.1644/09-MAMM-A-384.1.

Life cycle of Oithona similis (Copepoda: Cyclopoida) in Kola Bay (Barents Sea)

The annual population dynamics (nauplii, old copepodites CIV–CV and adults) and seasonal variations in reproductive parameters of the cyclopoid copepod Oithona similis were investigated on the basis of the data 1999–2006 in Kola Bay, a large subarctic fjord in the Barents Sea. Population density of O. similis ranged from 110 to 9,630 ind m−3 and averaged 1,020 ± 336 ind m−3. The relative abundance of adults was high during winter (~60%). At the end of winter (mid-March), the population included a large percentage of later-stage copepodites (stage CIV 23% and stage CV 57%). There were two periods of mass spawning, in late June and September. Autumn and summer generations strongly differed in abundance, average prosome length (PL), clutch size (CS), egg diameter (D), egg production rates (EPR and SEPR) and female secondary production. Average PL decreased with increasing water temperature, while D and CS were strongly correlated with PL but unaffected by temperature. Annual average EPR and SEPR were 0.55 ± 0.18 eggs female−1 day−1 and 0.0011 ± 0.003 day−1, respectively. Female secondary production averaged 0.8 ± 0.3 μg C m−3 day−1 (range 0.001–3.58). There were positive relationships between abundance, EPR, SEPR, production and water temperatures. Reproductive parameters appeared to be controlled by hydrological factors and food conditions.

GEOGRAPHIC VARIATION IN MATERNAL INVESTMENT: ACIDITY AFFECTS EGG SIZE AND FECUNDITY IN RANA ARVALIS

Environmental-stress-mediated geographic variation in reproductive parameters has been little studied in natural vertebrate populations outside the context of climatic variation. Based on life-history theory, an increase in the degree of environmental stress experienced by a population should lead to (1) a shift in reproductive allocation from fecundity to offspring quality, (2) stronger trade-offs between reproductive parameters, and (3) changes in the relationship between female phenotype and maternal investment. To test these predictions, we investigated geographic variation in maternal investment of moor frogs (Rana arvalis) in relation to breeding site acidity (pH 4-8). We found that mean egg size increased and clutch size and total reproductive output (TRO) decreased with increasing acidity among 19 Swedish moor frog populations. Tests for variation and co-variation in maternal investment and female size and age in 233 females from a subset of four acid origin (AO) and four neutral origin (NO) populations revealed that clutch size and TRO increased with female size in both acid and neutral environments. However, in AO populations, egg size also increased with female size, and clutch size and TRO with female age, whereas in NO populations, egg size increased with female age. The strength of the egg-size-clutch-size tradeoff tended to be stronger in AO than in NO females as expected if the former experience stronger environmental constraints. All in all, these results suggest that environmental acidification selects for investment in larger eggs at a cost to fecundity, imposes negative effects on reproductive output, and alters the relationship between female phenotype and maternal investment.

Spatiotemporal variation in reproductive parameters of yellow-bellied marmots

Spatiotemporal variation in reproductive rates is a common phenomenon in many wildlife populations, but the population dynamic consequences of spatial and temporal variability in different components of reproduction remain poorly understood. We used 43 years (1962-2004) of data from 17 locations and a capture-mark-recapture (CMR) modeling framework to investigate the spatiotemporal variation in reproductive parameters of yellow-bellied marmots (Marmota flaviventris), and its influence on the realized population growth rate. Specifically, we estimated and modeled breeding probabilities of two-year-old females (earliest age of first reproduction), >2-year-old females that have not reproduced before (subadults), and >2-year-old females that have reproduced before (adults), as well as the litter sizes of two-year old and >2-year-old females. Most reproductive parameters exhibited spatial and/or temporal variation. However, reproductive parameters differed with respect to their relative influence on the realized population growth rate (lambda). Litter size had a stronger influence than did breeding probabilities on both spatial and temporal variations in lambda. Our analysis indicated that lambda was proportionately more sensitive to survival than recruitment. However, the annual fluctuation in litter size, abetted by the breeding probabilities, accounted for most of the temporal variation in lambda.

Annual variation in reproductive parameters of Adélie penguins at Edmonson Point, Victoria Land, Antarctica

Annual egg and chick production and breeding success at the Adelie penguin (Pygoscelis adeliae) colony Edmonson Point (74°21′S–165°10′E), Victoria Land, is presented for eight breeding seasons between 1995 and 2005. During this period the colony consisted of 10–13 subcolonies and averaged 2098 ± 278 breeding pairs. A sample of over 100 nests (114–150), belonging to two subcolonies, was monitored each year. Some breeding parameters remained constant while others showed substantial annual variation. Laying date showed little variation, and laying was highly synchronous: 82.5% of clutches were initiated in a 10-day period, 9–18 November. In contrast, clutch size (1.77–1.97) and incubation period (34.4 ± 2.5) varied significantly. Variation among years was also recorded in hatching success (from 58 to 86%) and breeding success. This last parameter, measured as number of chicks reared to creche per nest with eggs, varied between 0.34 and 0.97.

Long-term studies on productivity of Roseate Terns and Lesser Noddies on Aride Island, Seychelles

This paper summarises up to 16 years of data on the productivity of Roseate Terns and Lesser Noddies on Aride Island, Seychelles, in order to assess: (1) the magnitude of variation in reproductive parameters, (2) the factors influencing their breeding success, and (3) whether common factors influenced the productivity of the two species. With the exception of 2002, the productivity of Lesser Noddies on Aride Island was always higher than that of Roseate Terns. The frequent mass mortalities of chicks on Aride were more common for Roseate Terns (an almost null productivity occurred in 44% of the years) than for Lesser Noddies (productivity less than 0.10 chicks per breeding pair occurred in only 20% of the years). Hatching success of both species was positively correlated, but there was no correlation for productivity, which suggests that stochastic variation in short-term food availability affected both species differently. Our results indicate that food shortage is the main factor explaining the breeding success of both species on Aride; the impact of other factors, such as tick infestation, depended upon the extent of food shortage. The underlying causes of food shortage are difficult to predict, although annual variation in marine productivity seems to be the ultimate factor determining productivity of Roseate Terns and Lesser Noddies.

Demographic and Female Life History Parameters of Free-Ranging Chimpanzees at the Chimpanzee Rehabilitation Project, River Gambia National Park

We analyzed fertility and mortality records for 113 provisioned, free-ranging chimpanzees at the River Gambia National Park, The Gambia. The chimpanzees are rehabilitated orphans released by the Chimpanzee Rehabilitation Project (CRP), and their descendants born in a natural environment. Females experienced their 1st births at an average age of 14.3 yr, with average interbirth intervals of 68 mo. Despite limited provisioning, reproductive parameters in both released and 1st-generation females resembled those of wild chimpanzees and showed seasonal fluctuations. Mortality rates were low compared to those for wild chimpanzees, particularly for infants and juveniles; life expectancy at birth was 23.6 yr for females and 18 yr for males. The results have implications for our understanding of variation in reproductive parameters between captive and wild chimpanzees. We also discuss issues related to chimpanzee conservation and captive rearing.

Reproductive performance of capybaras (Hydrochoerus hydrochaeris) in captivity under different management systems in Argentina

The capybara (Hydrochoerus hydrochaeris Linnaeus, 1766) is a wild rodent of great eco- nomic interest and is easily domesticated. Variations in reproductive parameters for the capybaras depend on both intrinsic and extrinsic factors, which modulate the different stages of its reproduc- tion either in captivity or wildlife. In captivity, an intensive production system is feasible, offering an economical profit under certain reproductive conditions. This work evaluates the reproductive performance of capybaras under different management systems in captivity, interpreting the results biologically and giving management guidelines to optimize their intensive production. The study was carried out at the Capybara Breeding Station, located in the Agricultural Experimental Station Delta del Parana, belonging to the National Institute for Agricultural Technology (INTA; Cam- pana, province of Buenos Aires, Argentina; 34 ◦ 08'S; 58 ◦ 12'W), from August 1997 to December 1998. Three different management systems were tested: System I Isolated pens (IP), composed of three different types of outdoor enclosures for reproduction, and growth. System II Isolated females (IM), formed by a central enclosure (reproduction pen), communicating with 12 paddocks (maternity pen) and growth pens. System III Mixed pens (MP), an enclosure of 35 × 10-m divided in area and maternity pens; the offspring were moved to growth pens elsewhere. A temporary weaning technique was tested for the mixed pens system. The variables analyzed for all systems were litter size at birth and at weaning, nursing and interbirth periods, and survival rates (at birth, weaning and total). The reproductive efficiency of each adult female was calculated as the total number of individuals weaned alive in a one-year period. During the study, 348 young were born in 104 births, from a total of 59 adult females. We conclude that the system that performs the best for capybara reproduction is the mixed pens system, including tem- porary weaning. Under this management strategy the following parameters were registered: mean litter size of 3.8 newborn per birth; 85% of live offspring at weaning; two births per year per female; all resulting in a reproductive efficiency of 6.5 young weaned alive per year × female. These repro- ductive parameters provide the necessary conditions to obtain economical profit of captive-bred capybaras. breeding management / capybara / captivity / production / reproduction

Pairs of extreme avian personalities have highest reproductive success

Summary Intraspecific variation in reproductive decisions is generally considered as a reaction to environmental circumstances. We show that variation in reproductive parameters also covaries with intraspecific variation in personality. During 4 years, we studied reproductive parameters in a natural population of great tits in association with a personality trait: exploratory behaviour as measured in a novel environment. Nest success, fledgling size and condition were all correlated with this personality trait. Slow‐exploring females had a higher nest success and largest fledglings. Fledgling condition was affected by the interaction between male and female exploratory behaviour, with assortative pairs at both ends of the behavioural spectrum producing fledglings in best condition. Fast‐exploring males bred in nestboxes that produced heavy fledglings in other years. We hypothesize that fast‐exploring individuals are better able in defending or obtaining a high quality territory, while slow‐exploring individuals are either better parents or have better chicks which may, in part, explain the patterns in reproductive success. We discuss how these patterns in reproduction can explain earlier reported relationships between offspring recruitment and avian personality and may result in the maintenance of intraspecific genetic variation in personality.

Reproductive Parameters of FemalePan paniscus and P. troglodytes: Quality versus Quantity

We investigated intra- and interspecific differences in life history and reproductive parameters in bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). We compare the parameters of wild and captive females in order to shed light on the influence of habitat or specific differences or both on reproduction. We present new and additional information on reproductive parameters from captive bonobos and chimpanzees. Captive chimpanzees birth more live offspring and have a shorter interbirth interval, but experience higher infant mortality than captive bonobos. Although captive bonobo females tend to start reproduction at a younger age than chimpanzees, this is effectively only so for wild-born females of both species. Ultimately both species reach the same rate of production of offspring surviving to 5 yr. These results contrast with data from the wild. Wild bonobos tend to have higher reproductive success, a higher fertility rate and a shorter interbirth interval than wild chimpanzees. Reproduction is similar for wild and captive bonobos, which suggests that they are producing at their maximum under both conditions. Overall captive chimpanzees perform better than their wild conspecifics, probably because of lower feeding competition. Infant survival is the only specific difference not affected by captivity. Bonobo infants survive better, which suggests that chimpanzee infants are more at risk. We argue that the interspecific variation in reproductive parameters in captivity is related to the different influence of captivity on reproduction and different pressures of external sources of infant and juvenile mortality.