Background: Fecundity is an important parameter in fisheries that predicts the reproductive capability of fish stock. Information on the fecundity of Common carp is helpful in estimating the amount ...of offspring produced in spawning season, which is essential for the stock assessment of the species. Assessment of the fecundity of a fish is essential for evaluating the commercial potentialities of its stock, life history, practical culture and actual management of the fishery. Common carp is a commercially important fish which has the potential to meet the demand of food in the country. Scanty of data is available on fecundity parameter of common carp in Kashmir waters. Therefore, this research work aims to estimate the fecundity of Common carp collected from the Dal lake of Kashmir.
Methods: The present study aims to estimate the fecundity of Common carp, Cyprinus carpio var. communis existing in Dal Lake, Kashmir. The 30 fish samples were collected once every month from the month of January 2018 to December 2018. Fishes were brought to Fisheries Resource Management (FRM), Faculty of Fisheries, SKUAST-K Laboratory for the estimation of total length, weight of fishes and weight of ovaries. Gravimetric and actual counting method was used for the estimation of fecundity. Result: It was observed that the number of eggs varied from 16650 (for a fish with total length 180mm and total weight 120 g) to 129000 (for a fish with total length 430 mm and total weight 1300 g. The mean absolute fecundity was recorded as 68864.07± 6563.59 for a fish with a mean total length of 301.43 ± 13.93 mm and mean total weight of 435.1 ± 66.51 g. The relative fecundity ranged from 99.2-240.8 and the mean relative fecundity was 185.96. Significant positive correlation was found between fish weight and absolute fecundity. (r= 0.907, p less than 0.01), fish length and absolute fecundity (r= 0.976, p less than 0.01), Ovary weight and absolute fecundity (r= 0.998, p less than 0.01). Relative fecundity showed a significant negative correlation with weight, length and absolute fecundity (r= -0.747, p less than 0.01; r= -0.419, p less than 0.05 and r= -0.460, p less than 0.05 respectively.
QUESTIONS: Is there any evidence of coordination among leaf, stem and root traits, and thereby of the existence of a plant economics spectrum at the species and community level in Mediterranean ...forests? Are these traits related to plant size and seed mass? LOCATION: Mediterranean forests and shrublands, Sierra Morena mountains, Córdoba, southern Spain. METHODS: We selected nine woody plant communities along a natural local gradient of soil water and nutrient availability. We measured key leaf, stem, root and whole‐plant traits for 38 dominant woody plant species. The variation across species of 15 functional traits (of the leaf, stem and root) was analysed and coordination among them was tested. We explored the relationships between these traits (hereafter ‘resource‐use traits’ due to their close association with the acquisition–conservation trade‐off) and plant height and seed mass. Finally, we compared results at species level with those calculated at community level, considering community‐weighted means (CWMs). RESULTS: We found a significant coordination between traits belonging to different plant organs, and propose the existence of a plant economics spectrum in Mediterranean forests along the environmental gradient. However, weaker relationships were found within groups of species under similar environmental conditions. We did not find the expected orthogonal relationships between plant height, seed mass and resource‐use traits. Relationships among functional traits were stronger at the community level than at the species level. CONCLUSIONS: This study reveals a high degree of functional coordination between traits belonging to different plant organs at both species and community level, and suggests the existence of a plant economics spectrum across 38 Mediterranean woody plant species. However, this general trend of functional coordination between organs became weaker or disappeared when considering restricted groups of species belonging to environmentally similar sites (e.g. dry vs wet sites), suggesting that the diversification of strategies within communities is not related to the economics spectrum at a lower spatial scale. Interestingly, the high degree of coordination between resource‐use traits and seed mass at the community level seems to support the tolerance–fecundity model, which predicts an inverse relationship between fecundity and stress tolerance.
Female fecundity is dependent on age and mated status. Young female insects accumulate considerable fat stores to fuel energetically expensive ovary development and egg production. Consequently, ...younger females are expected to have more stored fat than older females while the latter should have larger egg loads than the former. Mating is expected to increase fecundity because male ejaculates contain fecundity-enhancing substances that stimulate egg development, ovulation and oviposition. We experimentally tested the effect of female age (young versus old) and mated status (virgin versus mated) on fat and egg loads in female Gryllus firmus field crickets (Orthoptera: Gryllidae), in addition to testing the prediction that young or mated females have higher resting metabolic rates (RMR) than old or virgin females because the former should be significantly more engaged in the energetically expensive activity of egg production than the latter. As predicted, we found that young females had more fat and fewer eggs than old females and that fat loads negatively correlated with fecundity across all females. Young females also exhibited higher RMR, as expected if egg production is energetically costly. Contrary to expectation, however, mated status had little effect on fat load, egg production or RMR. That mating had little effect on total egg production (i.e. stored and oviposited eggs) challenges the hypothesis that male fecundity-enhancing substances in the ejaculate stimulate egg production. Our experiment also permitted us to examine the validity of two popular indices of body condition, the scaled mass index (SMI) and residual body mass (Ri). Neither index accurately represented the true treatment effects of age and mated status on fat load; however, the SMI reflected true fat content in young, but not old, females.
•We tested effects of age and mated status on fat and egg loads in female Gryllus firmus.•Young females had more fat and fewer eggs than old females.•Fat loads were negatively correlated with fecundity across all females.•Young females had a higher resting metabolic rate (RMR) than old females.•Mated status had little effect on fat load, egg production or RMR.
Multiple niche‐based processes including conspecific negative density dependence (CNDD) determine plant regeneration and community structure. We ask how interspecific and intraspecific ...density‐dependent interactions relate to plant life histories and associated functional traits. Using hierarchical models, we analysed how such interactions affected first‐year survival of seedling recruits of 175 species in a tropical forest, and how species abundances and functional traits are related to interspecific variation in density‐dependent effects. Conspecific seedling neighbour effects prevailed over the effects of larger conspecific and all heterospecific neighbours. Tolerance of seedling CNDD enhanced recruit survival and subsequent abundance, all of which were greater among larger seeded, slow‐growing and well‐defended species. Niche differentiation along the growth–survival trade‐off and tolerance of seedling CNDD strongly correlated with regeneration success, with manifest consequences for community structure. The ability of larger seeded species to better tolerate CNDD suggests a novel mechanism for CNDD to contribute to seed‐size variation and promote species coexistence through a tolerance–fecundity trade‐off.
Peroxisomes are ubiquitous cellular organelles participating in a variety of critical metabolic reactions. PEX14 is an essential peroxin responsible for peroxisome biogenesis. In this study, we ...identified the human PEX14 homolog in the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae). N. lugens PEX14 (NlPEX14) showed significant topological similarity to its human counterpart. It is expressed throughout all developmental stages, with the highest expression observed in adult insects. Down-regulation of NlPEX14 through injection of NlPEX14-specific double-strand RNA impaired nymphal development. Moreover, females subjected to dsNlPEX14 treatment exhibited a significantly reduced lifespan. Additionally, we found abnormal ovarian development and a significant decrease in the number of eggs laid in NlPEX14-downregulated females. Further experiments support that the shortening of lifespan and the decrease in female fecundity can be attributed, at least partially, to the accumulation of fatty acids and reduced expression of vitellogenin. Together, our study reveals an indispensable function of NlPEX14 for insect reproduction and establishes a causal connection between the phenotypes and peroxisome biogenesis, shedding light on the importance of peroxisomes in female fecundity.
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•Down-regulation of NlPEX14 impaired nymphal development.•Down-regulation of NlPEX14 reduced lifespan.•The expression of Vg reduced after down-regulation of NlPEX14.•Reduction in fecundity attributed to fatty acids accumulation.
This paper mainly aims at highlighting the differences in reproductive parameters of females of a lot of Palas Merino breed crossed with the Merino Palas breed male (group I) and a lot of Palas ...Merino females crossed with males of breed Ile de France (group II). Research has been conducted in a trading company in Vaslui county, on a herd of 600 female heads. The results showed that reproductive parameters of Merino sheep breed group crossed with rams of the breed Ile de France (group II) where higher compared to the Merino sheep breed group crossed with Merino rams (group I), given that environmental conditions were identical for two lots. So, the index of fecundity determinate had value of 92.00 %from the first batch of sheep and of 92.33 % for the second batch of sheep also The calculated prolificacy for the these two lots had values of 113.40 for the first lot and of 136.69% for the second lot. Note that two reproductive parameters analyzed a very significant difference was found in the prolificacy parameter. Of breeding parameters studied, a very significant difference was found in the prolificacy parameter.
Abstract
STUDY QUESTION
Does the long-term fecundity of women with polycystic ovary syndrome (PCOS) differ from those without PCOS?
SUMMARY ANSWER
Cumulative probability of childbirth is similar ...between women with and without PCOS.
WHAT IS KNOWN ALREADY
PCOS is the main cause of anovulatory infertility in women after menarche. Previous studies indirectly suggest that fecundity in women with PCOS over the longer term may not be lower than in women without PCOS.
STUDY DESIGN, SIZE, DURATION
This is a population-based study using four linked Swedish national registries. A total of 45 395 women with PCOS and 217 049 non-PCOS women were included. Follow-up began at the age of 18 years and continued for a maximum of 26 years, from 1989 to the end of 2015. Childbirth was the main outcome, as identified from the Medical Birth Register.
PARTICIPANTS/MATERIALS, SETTING, METHODS
All women born between 1971 and 1997 who were identified with a PCOS diagnosis in the Swedish Patient Registry between 1 January 2001 and 31 December 2016 were included in the study population. Five controls per women with PCOS were randomly drawn from the Total Population Registry. The control women were born in the same year and living in the same municipality as the patient. The fecundity ratio (FR) was calculated by clustered Cox regression using a robust variance, adjusted for maternal birth period, country of birth and level of education.
MAIN RESULTS AND THE ROLE OF CHANCE
The cumulative probability of childbirth was 80.2% (95% CI, 79.5–80.9%) in women with PCOS and 78.2% (95% CI, 77.9–78.5%) in those without PCOS. Adjusted FR was 0.81 (95% CI, 0.80–0.82) for first childbirth and 0.58 (95% CI, 0.57–0.60) for first childbirth following a spontaneous pregnancy. The FR for second childbirth was 0.79 (95% CI, 0.77–0.80). Women with PCOS had more than one child less frequently than the comparison group. Within the PCOS group, early age at diagnosis, later birth year, Nordic country of origin and low educational level positively influenced the FR.
LIMITATIONS, REASONS FOR CAUTION
Results are not adjusted for BMI, and time from intention to conceive to first childbirth could not be captured. Data on pregnancies, miscarriages or abortions and fertility treatment are unknown for women who did not give birth during the study period. Women with PCOS who did not seek medical assistance might have been incorrectly classified as not having the disease. Such misclassification would lead to an underestimation of the true association between PCOS and outcomes.
WIDER IMPLICATIONS OF THE FINDINGS
While cumulative probability of childbirth is similar between groups, women with PCOS need longer time to achieve their first childbirth. Women with PCOS have a lower FR and give birth to fewer children per woman than women without PCOS. Early diagnosis of and information about PCOS may improve affected women’s reproductive potential.
STUDY FUNDING/COMPETING INTEREST(S)
This study was funded by the Swedish Society of Medicine. Inger Sundström Poromaa has, over the past 3 years, received compensation as a consultant and lecturer for Bayer Schering Pharma, MSD, Gedeon Richter, Peptonics and Lundbeck A/S. The other authors declare no competing interests.
Although density regulates the abundance of most wild animal populations by influencing vital rates, such as fecundity and survival, the mechanisms responsible for generating negative density ...dependence are unclear for many species. Site dependence occurs when there is preferential filling of high-quality territories, which results in higher per capita vital rates at low densities because a larger proportion of occupied territories are of high quality. Using 41 yr of territory occupancy and demographic data, we investigated whether site dependence was a mechanism acting to influence fecundity and, by extension, regulate a population of Canada Jays in Algonquin Provincial Park, Ontario, Canada. As predicted by site dependence, the proportion of occupied territories that were of high quality was negatively correlated with population density and periods of vacancy were shorter for high-quality territories than for low-quality territories. We also found evidence that per capita fecundity was positively related to the proportion of occupied territories that were of high quality, but only when environmental conditions, which influence the entire population, were otherwise poor for breeding. Our results suggest that site dependence likely plays a role in regulating this population but that environmental conditions can modulate the strength of density dependence.
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