Variations in reproductive strategies between one invasive population and two native populations of Pseudorasbora parva

Reproductive traits of one invasive population in Lake Fuxian and two native populations in Lakes Chao and Dongting for Pseudorasbora parva were investigated to determine the variations in their reproductive strategies associated with the change of environmental conditions. Compared with the two native populations, P.parva markedly experienced the protraction in their spawning time and the decrease in mortality for adult individuals in Lake Fuxian. The three populations all got their first sexual maturity at the same age, but their total lengths at maturity were quite different for those in Lake Chao were significantly lower than in Lakes Fuxian and Dongting. Additionally, in spite that no significant difference occurred in their relative fecundities for P. parva in Lakes Fuxian and Dongting, the population in Lake Chao showed the markedly higher relative fecundity than the other two populations. These results were analyzed with the variations in water temperature, nutrient status, fishing stress among the three lakes. The relative decline in fecundity for the invasive population, which conflicted with the enemy release hypothesis, was disscussed with the context of the preponderance of another invasive fish, Neosalanx taihuensis, in Lake Fuxian.

Reproductive strategies and seeds behavior of Betula platyphylla Suk. Population

By the methods of morphological anatomy and investigation in the sample fields, the main studies were carried out such as morphological anatomy of reproductive organs, birch population’s reproductive ages, reproductive allotment value and seed behavior. The relationship between birch population and their surroundings was studied. The results showed that birch’s flower organs and its seeds were suitable well for spreading by wind. The seeds by wind can fly far away in a short time. The quantity of seed spreading greatly varied with different communities. Birch’s reproduction age can be changed in different ecological surroundings. The reproductive allotment value of birch was obviously different at different reproductive stages. In the mesic habitat, birch can grow well. The lowest reproductive age of them was 12, average age 15. In most cases the age of branches to bearing fruits was more than 18. The order of reproductive allotment values was as follows: a flowering phase > flower bud phase > fruit phase.

Genome-wide SNP markers provided insights into the reproductive strategy and genetic diversity of the green tide causative species Ulva prolifera in China

Ulva prolifera is the causative species of the annually occurring large-scale green tides in China since 2007.Its specific biological features on reproductivity strategies,as well as intra-species genetic diversity,are still largely unknown,especially at the genome level,despite their importance in understanding the formation and outbreak of massive green tides.In the present study,the restriction site-associated DNA genotyping approach(2b-RAD)was adopted to identify the genome-wide single-nucleotide polymorphisms(SNPs)of 54 individual thalli including samples collected from Subei Shoal in 2019 and Qingdao coast from 2019 to 2021.SNPs genotype results revealed that most of the thalli in 2019 and 2020 were haploid gametophytes,while only half of the thalli were gametophytes in 2021,indicating flexibility in the reproductive strategies for the formation of the green tides among different years and the dominance of asexual and vegetative reproductive mode for the floating period.Besides,population analysis was conducted,and it revealed a very low genetic diversity among samples from Subei Shoal and the Qingdao coast in the same year and a higher divergence among samples in different years.The results showed the efficiency of 2b-RAD in the exploration of SNPs in U.prolifera and provided the first genome-wide scale evidence for the origin of the large-scale green tides on the Qingdao coast.This study improved our understanding of the reproductive strategy and genetic diversity of the green tide causative species and will help further reveal the biological causes of the green tide in China.

Differences in functional traits and reproductive allocations between native and invasive plants

Because co-occurring native and invasive plants are subjected to similar environmental selection pressures,the differences in functional traits and reproductive allocation strategies between native and invasive plants may be closely related to the success of the latter.Accordingly,this study examines differences in functional traits and reproductive allocation strategies between native and invasive plants in Eastern China.Plant height,branch number,reproductive branch number,the belowground-to-aboveground biomass ratio,and the reproductive allocation coefficient of invasive plants were all notably higher than those of native species.Additionally,the specific leaf area(SLA)values of invasive plants were remarkably lower than those of native species.Plasticity indexes of SLA,maximum branch angle,and branch number of invasive plants were each notably lower than those of native species.The reproductive allocation coefficient was positively correlated with reproductive branch number and the belowground-to-aboveground biomass ratio but exhibited negative correlations with SLA and aboveground biomass.Plant height,branch number,reproductive branch number,the belowground-to-aboveground biomass ratio,and the reproductive allocation coefficient of invasive plants may strongly influence the success of their invasions.

Impacts of grazing and mowing on reproductive behaviors of Stipa grandis and Stipa krylovii in a semi-arid area

Disturbance can affect biomass allocation of plants,but can it influence plant reproductive behavior?To address this issue,we performed field plant community investigations and explored the reproductive behaviors of Stipa grandis and Stipa krylovii in response to grazing and mowing treatments at Maodeng pasture of Xilinguole League of Inner Mongolia,China during 2007–2009.The results showed that,with a similar niche width for the two plant species under mowing and grazing treatments,mowing significantly increased the ratio of ramet to genet number of S.krylovii and the carbon to nitrogen ratio of S.grandis,and grazing significantly decreased the ratio of vegetative to reproductive tiller biomass of S.grandis and increased the ratio of vegetative to reproductive tiller number of S.krylovii.Regression analysis showed that the significantly positive effect of root to shoot biomass ratio was stronger on the ratio of vegetative to reproductive tiller number of S.grandis than on that of S.krylovii.These results indicated that grazing and mowing influenced the reproductive manner and the process of sexual reproduction of S.grandis and S.krylovii.

Mating and reproductive characteristics of the pathogenic nematode Bursaphelenchus xylophilus

Pine wood nematode(B ursaphelenchus xylophilus),one of the most destructive invasive species,has caused extremely serious economic,ecological and social losses in many countries throughout the world.Since the high reproductive rate of B.xylophilus PWN is the main cause of rapid death of its pine hosts(Pinus spp.),understanding the reproductive and population biology and the ecology of this nmatode are of great importance.This study mainly focused on analyzing the mating process and population structure under different combinations of sex ratios for mating.Reproductive efficiency of B.xylophilus peaked when the sex ratio(female to male)was 3.4:1.Phases of the mating process for the different sex-ratio combinations indicated that B.xylophilus had evolved alternative reproductive strategies to cope with complex copulating conditions to obtain a suitable population structure for further propagation.This research provides fundamental information on the mechanism that is responsible for the rapid population growth of B.xylophilus.

Egg investment strategies adopted by a desertic passerine, the Saxaul Sparrow(Passer ammodendri)

Background:As one of the reproductive strategies adopted by bird species,variation in investment in egg production and its influencing factors are important and well-studied subjects.Intraclutch changes in egg size associated with laying order may reflect a strategy of"brood survival"or"brood reduction"adopted by female birds in different situations.Methods:We conducted field studies on the breeding parameters of the Saxaul Sparrow(Passer ammodendri)in Gansu Province,China from 2010 to 2017,to clarify the factors affecting the egg investment and reproductive performance of this passerine species.Results:Our results revealed significant differences in clutch size,egg size and the fledging rate between the first and second brood of Saxaul Sparrows and suggested that this typical desert species allocates more breeding resources to the more favourable second brood period,leading to greater reproductive output.Female body size presented a positive relationship with egg size,and male body size presented positive relationships with clutch size and hatchability.The females that started their clutches later laid more eggs,and hatchability and the fledging rate also increased with a later laying date in the first brood period.With successive eggs laid within the 5-egg clutches(the most frequent clutch size),egg size increased for the first three eggs and then significantly decreased.Conclusions:Our results indicate that female Saxaul Sparrows increased egg investment because of good quality of paired males and good environmental conditions.The intraclutch variation of egg size suggests that this species inhabiting an arid environment adopts a"brood reduction"strategy.

Haloxylon ammodendron (Amaranthaceae) fruit development delay caused by post-flowering non-inductive photoperiod

Haloxylon ammodendron （C. A. Mey.） is one of the economically and ecologically important desert trees used for sand fixation. The ovary of H. ammodendron is found not to swell after flowering in spring until at the end of August or early September in western China. However, what happens for ovary at anatomic level in that period and which crucial ecological factor regulates the phenomenon of H. ammodendron have not been fully understood. To characterize the phenomenon and explore the crucial environmental regulating factors, we carried out the morphological and anatomic observations at the different development stages of the fruits and three single-factor experiments （low air temperature, sufficient soil moisture, and short day length）. Our results showed that under the natural conditions, the ovary of H. ammodendron after flowering developed slowly and the morphological changes of fruits were not significant for the period from May to August and after late August or early September; and then the ovary developed rapidly and matured in October. Cell division in embryo was observed to start approximately 25 days after flowering （DAF） and just developed to globular embryo stage at mid-August. Photoperiod was identified as the pivotal environmental factor regulating the fruit development of H. ammodendron. Moreover, the threshold value of day length for the fruit development was 14.0 h. A long day （〉14.0 h） treatment began from 5 DAF could delay fruit development of H. ammodendron while a short day （〈14.0 h） treatment could accelerate it. Moreover, a further longer day treatment （〉15.0 h） could also delay fruit development even when they had developed for a long time （110 DAF）. The present study indicated that H. ammodendron adopted a reproductive strategy of delayed fruit development and this strategy helps it survive and obtain offspring in harsh desert habitats.

Male parent birds exert more effort to reproduce in two desert passerines

Background:Parental investment by birds is limited by the habitat environment,and a male parent increases its effort to reproduce in birds that live in high-altitude areas.Methods:A study of the reproductive behaviour of the Saxaul Sparrow(Passer ammodendri)and the Isabelline Shrike(Lanius isabellinus)was carried out at the Gansu An’xi Extremely Arid Desert National Nature Reserve in northwest China to determine the reproductive input of passerine species in desert habitats.Results:In Saxaul Sparrows,compared to the female parent,the male parent exhibited a significantly higher fre-quency of nest-defense behaviour(chirping and warning)during nesting,hatching and feeding periods.In addition,in comparison to the female parent,the male parent exhibited almost equal frequencies of nesting and incubation but fed nestlings significantly more times.Similar to the male sparrows,the feeding rates of the male Isabelline Shrikes were significantly higher than those of the females.The hatching rate and fledging rate of the Saxaul Sparrow on aver-age in this study were 81.99 and 91.92%,respectively,while those of the shrike were 69.00 and 96.53%,respectively.Conclusions:These two different passerine species living in the same desert environment exhibited the same trend in their reproductive investments.Adapting to desert environments is a strategy that may have evolved in passerines where male parent birds put more effort than females into reproduction to ensure high reproductive output.

Reproductive biology in an invasive plant Solidago canadensis

Solidago canadensis,a perennial Compositae plant originating from North America,was introduced into China as a horticultural plant in 1935.Under natural condi-tions,S.canadensis allocates large amounts of energy to sexual reproduction and produces many seeds,which reflects an r-strategy with high seed number and small seed size.In addition,naturalized populations have a great capacity to grow clonally with underground stems.S.canadensis has become an invasive weed in eastern China,and has caused serious damages to agricultural production and ecosystems in several provinces in China.In order to understand the reproductive characteristics of S.canadensis and effectively control its spread,we examined soil conditions,seed charac-teristics,seed germination and the capacity for asexual reproduction in different plant parts.We investigated the population dispersion of S.canadensis in fixed sites for three years,and analyzed the seasonal dynamics of the morphological parameters of the underground parts and the caloric values of different organs of S.canadensis.We also compared differences in the root systems of S.canadensis and composite exotic weeds.The following results were obtained:1)Under natural conditions,the germination season of S.canadensis lasts from March to October,with a peak from April to May.Vegetative growth and asexual reproduction are especially vigorous during summer due to high temperatures and soil drought stress.On the other hand,the rainy season proves suitable for seed germination.Most S.canadensis flower between September and January,and fruit in late October.A mature plant can produce about 20000 seeds.The mean weight of 1000 seeds ranges from 0.045 g to 0.050 g,and the mean seed moisture content ranges from 60%to 80%.The light-winged seeds disperse readily by air,water,vehicles,human activity or through livestock.2)S.canadensis seeds have a wide tolerance for different values of pH,salinity and soil moisture.The mean percent germination of seeds is 30%under suitable conditions.The results of seed germination under various environmental stresses and investigation of soil conditions indicate that well-aerated,slightly acidic soils with low salinity are suitable for the growth of S.canadensis.Additionally,S.canadensis has a high tolerance for contamination by heavy metal elements including Zn,Cu and Pb,but has low accumulation coefficients for these elements.3)S.canadensis reproduces asexually via underground rhizomes and nodes on the stem base to recruit new individuals,and in plants that experience mechanical damage,this repro-ductive strategy is used to produce clonal shoots.The capacity for asexual reproduction among different plant parts rank as follows:underground parts>stem-base(20 cm)>stem-base(30 cm)>stem-base(45 cm)>stem.Further,with increasing mechanical damage,the quantity of shoots produced by the plant decreases.4)The morphological parameters of the root system of S.canadensis including length,surface area,volume,and average diameter are greater than for composite exotic weeds.These parameters indicate that S.canadensis has the physiological potential to widely invade China.5)The aboveground growth rate and most of the underground morphological parameters vary remarkably among the seasons,with a peak normally occurring in September.In August,a fraction of the energy in leaves and stems is allocated underground to increase fine root growth and water uptake during hot weather.Additionally,the seasonal dynamics of the underground morphological parameters and the caloric values of different organs of S.canadensis enhance its reproductive ability.Based on the results above,we conclude that S.canadensis has great invasive potential in China.We suggest that urgent measures should be taken to control its further spread,and to minimize its impact on local plant diversity.

Pheromones emitted by both female and male moths regulate coordination between the sexes for Agriphila aeneociliella (Lepidoptera: Crambidae)

The complex and efficient sex pheromone communication system in insects is essential for reproduction and for reproductive isolation of species.In moths,sex pheromone communication starts with male attraction to compounds emitted by females;only a few species act in the reverse.However,how the pheromones that are emitted by both sexes co-regulate and coordinate mate finding and mating remains unknown.Here,we identified both the male and female pheromones of Eastern Grass Veneer moth,Agriphila aeneociliella(Lepidoptera:Crambidae),and demonstrated their efficiency in manipulating behavioral responses of the opposite sex.Combining data from analysis of gas chromatography-electroantennogram detection,gas chromatography-mass spectrometry,and olfactory behavior assays,the female pheromone of A.aeneociliella was identified as(Z,Z,Z)-9,12,15-octadecatrienal and(Z)-9-hexadecenyl acetate,while the male pheromone was determined to be 1-nonanal.Both the 2 individual components of the female pheromone and their binary mixture were significantly attractive to males,and the 1-nonanal male pheromone induced strong electrophysiological responses in females and induced attraction of females in a Y-tube olfactory test.Depending on the concentration of 1-nonanal,its addition to the binary mixture of the female pheromone either enhanced(10^(−3) or 10^(−2)μg/μL)or reduced(1μg/μL)the aphrodisiac effect of the mixture on males.In wind-tunnel bioassays,different concentrations of pheromones,including the binary mixture of female pheromone and the mixture of male and female pheromones,had significant effects on male behavior.Our findings suggested that the blend of both female and male pheromones plays a significant role in the sexual communication system in some moths.

Social buffer or avoidance depends on the similarity of stress between queen ants

The association of unrelated ant queens(pleometrosis)is supposed to improve nest foundation and competitiveness under environmental stress,but its evolutionary maintenance is difficult to explain because only one of the queens survives after nest foundation.My aim was to test the potential effect of queen association as a social buffer,that is,as a mechanism reducing stress and improving fitness due to the benefits of social contact.I analyzed the survival,fecundity,and behavior of isolated and paired Lasius flavus queens exposed and not exposed to stressors(disturbing environmental conditions).I found no difference in survivorship between isolated and paired queens or between stressed and unstressed isolated queens.Groups in which 1 or 2 paired queens were stressed showed higher mortality.Unstressed queens died similarly to their stressed nestmates,suggesting stress transmission.A trend suggested that paired queens produced eggs more quickly,but eggs were produced similarly between isolated and paired queens.Social avoidance was observed in groups with 1 stressed and 1 unstressed queen.However,the groups with 2 stressed queens showed the expected behaviors according to social buffering:lower mobility and more interindividual inspection.My findings suggest the synergistic effect of pleometrosis and stress and the dependence of stress level similarity between nestmates on social buffering or rejection on ant queens.

Genetic basis and biotechnological manipulation of sexual dimorphism and sex determination in fish

Aquaculture has made an enormous contribution to the world food production,especially to the sustainable supply of animal proteins.The utility of diverse reproduction strategies in fish,such as the exploiting use of unisexual gynogenesis,has created a typical case of fish genetic breeding.A number of fish species show substantial sexual dimorphism that is closely linked to multiple economic traits including growth rate and body size,and the efficient development of sex-linked genetic markers and sex control biotechnologies has provided significant approaches to increase the production and value for commercial purposes.Along with the rapid development of genomics and molecular genetic techniques,the genetic basis of sexual dimorphism has been gradually deciphered,and great progress has been made in the mechanisms of fish sex determination and identification of sex-determining genes.This review summarizes the progress to provide some directive and objective thinking for further research in this field.

Sex determination mechanisms and sex control approaches in aquaculture animals

Aquaculture is one of the most efficient modes of animal protein production and plays an important role in global food security.Aquaculture animals exhibit extraordinarily diverse sexual phenotypes and underlying mechanisms,providing an ideal system to perform sex determination research,one of the important areas in life science.Moreover,sex is also one of the most valuable traits because sexual dimorphism in growth,size,and other economic characteristics commonly exist in aquaculture animals.Here,we synthesize current knowledge of sex determination mechanisms,sex chromosome evolution,reproduction strategies,and sexual dimorphism,and also review several approaches for sex control in aquaculture animals,including artificial gynogenesis,application of sex-specific or sex chromosome-linked markers,artificial sex reversal,as well as gene editing.We anticipate that better understanding of sex determination mechanisms and innovation of sex control approaches will facilitate sustainable development of aquaculture.

Sexual conflict and deception in poison frogs

I review evidence that females deceive males in the context of sexual selection and sexual conflict in the green poison frog, Dendrobates auratus. In this species, males mate polygynously when they have the opportunity, but polygyny imposes a cost on female reproductive success. Some females attempt to guard their mates when those males are approached by other fe- males. This behavior involves both aggression toward other females and active ＂pseudo-courtship＂ of the male. This courtship is hypothesized to be a deceptive signal that ffmctions to prevent the male from mating with other females. Observational and com- parative evidence is presented in support of the predictions of this hypothesis. This form of deception is compared to similar be- haviors that occur in other species, and the possibility that other forms of deception occur in poison frogs is discussed

Adult size and tinning of reproduction in five species of Asobara parasitoid wasps

The majority o f adult parasitoid wasps are unable to synthesize lipids and therefore face a trade-off between the investment of lipids in eggs or in the maintenance of soma.It has been shown that resource allocation should depend on body size in parasitoids.Given that smaller females have shorter expected life times,they should concentrate their reproductive effort into early life.To test this prediction,we investigated the relationship between body size and the timing of egg production in parasitoids.We measured body size,lipid reserves,and reproductive investment(number of eggs,ovigeny index equivalent[OIE]and egg size)at eclosion in five species of Asobara(Hymenoptera:Braconidae)originating from different geographic and climatic environments.Our results show significant interspecific variation in all these traits.A diagnostic test for phylogenetic independence revealed that closely related species did not resemble each other more closely than expected by chance for all traits measured.Lipid reserves scaled positively with body size both between and within species.In agreement with theory,01 correlated negatively with body size both between and within species.Total egg area at eclosion correlated negatively with lipid reserves both between and within species.This indicates the existence of a trade-off between allocation of lipids to current reproduction and survival/future reproduction.With the exception of the most extreme pro-ovigenic species,A.pers im ilis,we found that proovigeny was compensated for by small egg size.Our results indicate the role of habitats in shaping interspecific variation in resource allocation strategies.

Trait allometries generate super-honesty in Anolis dewlaps and may underlie sexual dimorphism

Whether or not sexually selected traits consistently exhibit positive allometry(i.e.are disproportionately large in larger individuals)is an ongoing debate.Multiple models and exceptions to this rule suggest that the underlying drivers of sexual trait allometry are nuanced.Here,we compare allometries of sexual and non-sexual traits of a species(Anolis aquaticus)within a well-studied lizard genus to test the competing hypotheses that sexual traits are,or are not,defined by positive allometry.We further consider the relationships of trait functions,which are relatively well understood in the genus Anolis,and allometry to identify potential drivers of allometric patterns.In particular,we explore how trait allometries interact to influence total organism function and generate sexual dimorphism.We quantified size(of targeted traits)and color of a sexual signal(the dewlap)in Anolis aquaticus in the field.The dewlap conveyed information relevant to intra-sexual combat and exhibited positive allometry.Overall,our results suggest that using single-trait allometries as indicators of past selection provides only an incomplete understanding of trait evolution.Although the function of positive allometry in some individual sexual signals(e.g.those conveying“super-honest”information)may be straightforward,we illustrate how scaling relationships interact synergistically to influence the function of phenotypes and propose avenues for future research.

Guideline for Diagnosis and Treatment of Infertility in Advanced Age Women(Revised Edition)

As more and more couples postpone their childbearing plan,and Chinese two-child policy is fully liberalized,the proportion of advanced-age parents gradually increases.However,ovarian function gradually descends with age,and the incidences of uterine fibroids,scarred uterus,and pelvic inflammation disease significantly increase,which increases the risk of infertility.Even though the advanced-age women successfully get pregnant through assisted reproductive technology(ART),the risks of pregnancy complications and medical and surgical complications(such as miscarriage,gestational diabetes,gestational hypertension,intrauterine fetal death,low birth weight of newborn,or premature birth)will increase with age.Currently,the consistency of diagnosis and treatment strategies on elderly patients with infertility is still lacking,and the efficacy of the diagnosis and treatment is even worse.In light of the above situations,the specialized committee organized experts of reproductive endocrinology and ART to compose this guideline,aiming for standardizing the process of diagnosis and treatment on advanced-age infertile women.This guideline interprets reproductive status and related fertility evaluation on advanced-age infertile women,and discusses prepregnancy preparation of body and nutrition and consultation,as well as related risk assessment of pregnancy.It also analyzes the current clinical and laboratory hot issues:the genetic characteristics of advanced-age women,evaluation,counseling,and corresponding laboratory screening,diagnostic methods,and operational norms.In addition,for the advanced-age women with high incidence of medical and surgical complications,this guideline gives us norms of diagnosis and treatment on different complications.Finally,strategies of ART are made for the advanced-age infertile women,which can provide basis and guidance for their diagnosis and treatment.

Genetic analysis of group composition and relatedness in white-headed langurs

We collected fecal samples of white-headed langurs from 3 of the 4 remaining habitat fragments(Fa,Fb and CZ)located in southwestern Guangxi,China in Nov 2005,and used 5 microsatellite loci and the SRY gene to assess the relatedness between 46 langurs within and between groups.We observed 2 forms of group structure:one-male/multi-female groups(OMGs)and all-male groups(AMGs).One AMG in Fa was composed of 2 generations,included a father,2 sons and 1 unrelated male,and all OMGs in all 3 habitats included 1 resident male,several adult females and offspring.Of the 21 identified father-offspring cases,the resident male fathered 20(95%)and the non-resident male sired 1(5%),suggesting that adult males had overwhelming priority of access to females as the resident male in an OMG,while the non-resident male may also have the opportunity to adopt surreptitious mating strategies.