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PubMed1992

Some biological effects of Bayluscide on Physa acuta and Helisoma duryi.

The fecundity, viability and the size of egg-masses were studied in Physa acuta and Helisoma duryi snails treated with 1 ppm Bayluscide for two hours. Bayluscide application caused significant and highly significant reduction in the fecundity of both Physa acuta and Helisoma duryi. However, an increase in the fecundity was observed for both treated snails in few days after exposure. Moreover, Bayluscide did not lead to stoppage of egg laying at any day of experiment. Bayluscide caused a reduction in the viability of egg-masses produced by treated Physa acuta or Helisoma duryi snails since they produced higher numbers of abnormal eggs containing dead embryo. Moreover, application of 1 ppm Bayluscide for two hours against Physa acuta caused a decrease in the size of egg-masses produced by treated snails. This is expressed by the production of higher percentage of egg-masses containing small numbers of eggs as compared with those masses produced by control snails.

Animals↗

PubMed2003

[Influence of genotype on endoreduplication of giant chromosomes and expressivity of character eyeless in Drosophila melanogaster].

In Drosophila melanogaster lines LA (low activity), HA (high activity), and Oregon-R (wild type), the effect of genetic background on endoreplication in giant chromosomes of salivary glands, fecundity, and expression of mutation ey was studied. The degree of chromosome polyteny and the number of adult flies in saturated lines eyHA, eyBA, and eyOr were significantly higher than in the original lines. The degree of chromosome polyteny was correlated with fecundity. The expressivity of the ey character was shown to be far lower in lines eyLA, eyHA, and eyOr than in the original eyeless line. In the saturated lines, the eye facets were reduced to a similar degree. All the lines studied displayed clear-cut sexual distinctions in this parameter. In the eyHA line, the coefficients of variation for the degree of chromosome polyteny, fecundity, and expressivity of the ey mutation were much lower than in lines eyeless, eyLA, and eyOr.

Animals↗

PubMed2003

[Influencing factors on the level of the ovulation rate in sheep during the main breeding season--an ultrasonographic study].

The main breeding season for sheep in Germany is from the beginning of September until the end of November. The aim of this study was to determine the factors which influenced the level of the ovulation rate (o. r.) during this period. The examination was conducted over three years and included Booroola. Mutton Merino crosses [heterozygous- (F+) carriers and non-carriers of the Booroola- (FecB) fecundity gene], German Mutton Merino (GMM) and German Blackheaded (GB). In total 1326 examinations were carried out. Between the 8th to 12th day after estrous detection an ovary diagnosis was performed by transrectal scanning with a 7.5 MHz linear probe. The number of the corpora lutea per ewe (o. r.) was documented. The weight and the body condition of the ewes was also determined. During the breeding season the breed of the ewe had the main effect on the level of the o. r. (p < 0.05). This is the reason that the statistical model can only be applied for each breed. The effects of age, year of examination and day of the main breeding season were tested. The age of the ewes and the date of the examination during the breeding season had the main effect on the o. r. In GMM and GB the age influenced the o.r. with an effect of 8.3% and 4.2%. The effect of the season was vice versa (Gmm 3.2%; GB 8.2%). Non-carriers of the Booroola- (FecB) fecundity gene behaved similar like the GMM. However, only the high fecundity carriers of the FecB-gene were strongly influenced by the season. For each breed there exists a typical threshold value for the body weight above which further weight has no effect on the o. r. (GMM 65-70 kg, GB 75-80 kg, non-carriers of the Booroola-FecB gene 55-60 kg and carriers of the FecB-gene 60-65 kg). This value lies at about 80% of the highest measured weight of each breed. The results demonstrated that a balanced age structure in combination with a optimum weight influenced the level of o. r. In addition the date of the season is especially important.

Age Factors↗

PubMed2004

[Prophylactic effect of artesunate against experimental infection of Schistosoma mansoni].

OBJECTIVE: To study the prophylactic effect of artesunate against the infection of Schistosoma mansoni in mice and its optimal scheme for preventing schistosomiasis mansoni. METHODS: BALB/c mice were infected by tail dipping method with S. mansoni cercariae. Mice were administered orally with artesunate at different developmental stage of the parasite, with different regimens. The reduction rates of total and female worms, the number of eggs in the liver and intestine, and the fecundity were calculated and treated statistically. RESULTS: The optimal dosage of artesunate to prevent murine schistosomiasis was 300 mg/kg. The parasite was found to be especially susceptible to artesunate in its schistosomula stage of 14 and 21 d after infection, resulting in worm reduction rate of 84% and 93% respectively compared with control. High protection was reached with worm reduction rate of 99% by the regimens of 300 mg/kg once a week for 4 consecutive weeks beginning 14 d after infection. The fecundity was significantly suppressed, suggesting that the drug inhibited sexual maturation of female worms. The effective protection could also be gained with prolonged interval time of two weeks with worm reduction rate of 97% and 96% beginning 14 or 21 d after infection. CONCLUSION: Artesunate kills schistosomula and reduces the fecundity of females effectively, the infected mice do not develop schistosomiasis mansoni when treated with artesunate. It's proposed that an optimal scheme for field use be the first administration 14 or 21 days after infection with 1 or 2 weeks interval.

Animals↗

PubMed2003

Growth and reproductive biology of loaches Cobitis sp. in Lake Lucień, Poland.

Five age-classes and their corresponding average body lengths of loaches from Lake Lucień were determined by the Bhattacharya method. The maximum observed length was 112 mm for females and 91 mm for males. The von Bertalanffy equation defining growth pattern was L(T) = 116 (1-exp (-0.401(t+0.02. Body length distribution of females and males differed significantly (chi2 = 91.295; df=9; P<0.00). Sex ratio showed the dominance of females in the studied population (M:F = 1:1.75; chi2 =18.00; P<0.01). Females were sexually mature at 56 mm TL and males at 52 mm TL. Female gonad weight increased with body size. The frequency distribution of egg diameters revealed 3 groups of oocytes. The average absolute fecundity was 2180 eggs and ranged from 418 to 6800 per gonad. The number of the largest oocytes (>0.6 mm in diameter) ranged from 208 to 975 (average 501) and was used to estimate fecundity at the moment of spawning. Both fecundity measures are related to body length of females their regression lines were parallel and did not differ in the coefficient of slope. The gonadosomatic index value, as an approximate measure of reproductive effort, was rather small (average IGS = 10.44 ranged from 5.12 to 17.88).

Animals↗

PubMed2005

Geographic variation in diapause incidence, life-history traits, and climatic adaptation in Drosophila melanogaster.

In Drosophila melanogaster, exposure of females to low temperature and shortened photoperiod can induce the expression of reproductive quiescence or diapause. Diapause expression is highly variable within and among natural populations and has significant effects on life-history profiles, including patterns of longevity, fecundity, and stress resistance. We hypothesized that if diapause expression is associated with overwintering mechanisms and adaptation to temperate environments, the frequency of diapause incidence would exhibit a latitudinal cline among natural populations. Because stress resistance and reproductive traits are also clinal in this species, we also examined how patterns of fecundity and longevity varied with geography and how stress resistance and associated traits differed constitutively between diapause and nondiapause lines. Diapause incidence was shown to vary predictably with latitude, ranging from 35% to 90% among natural populations in the eastern United States Survivorship under starvation stress differed between diapause and nondiapause lines; diapause phenotypes were also distinct for total body triglyceride content and the developmental distribution of oocytes in the ovary following stress exposure. Patterns of longevity, fecundity, and ovariole number also varied with geography. The data suggest that, for North American populations, diapause expression is functionally associated with overwintering mechanisms and may be an integral life-history component in natural populations.

Adaptation, Biological↗

PubMed2006

An analysis of continent-wide patterns of sexual selection in a passerine bird.

Patterns of selection are widely believed to differ geographically, causing adaptation to local environmental conditions. However, few studies have investigated patterns of phenotypic selection across large spatial scales. We quantified the intensity of selection on morphology in a monogamous passerine bird, the barn swallow Hirundo rustica, using 6495 adults from 22 populations distributed across Europe and North Africa. According to the classical Darwin-Fisher mechanism of sexual selection in monogamous species, two important components of fitness due to sexual selection are the advantages that the most attractive males acquire by starting to breed early and their high annual fecundity. We estimated directional selection differentials on tail length (a secondary sexual character) and directional selection gradients after controlling for correlated selection on wing length and tarsus length with respect to these two fitness components. Phenotype and fitness components differed significantly among populations for which estimates were available for more than a single year. Likewise, selection differentials and selection gradients differed significantly among populations for tail length, but not for the other two characters. Sexual selection differentials differed significantly from zero across populations for tail length, particularly in males. Controlling statistically for the effects of age reduced the intensity of selection by 60 to 81%, although corrected and uncorrected estimates were strongly positively correlated. Selection differentials and gradients for tail length were positively correlated between the sexes among populations for selection acting on breeding date, but not for fecundity selection. The intensity of selection with respect to breeding date and fecundity were significantly correlated for tail length across populations. Sexual size dimorphism in tail length was significantly correlated with selection differentials with respect to breeding date for tail length in male barn swallows across populations. These findings suggest that patterns of sexual selection are consistent across large geographical scales, but also that they vary among populations. In addition, geographical patterns of phenotypic selection predict current patterns of phenotypic variation among populations, suggesting that consistent patterns of selection have been present for considerable amounts of time.

Age Factors↗

PubMed2006

Biological and ecological studies on the myiasis producing larvae of Megaselia scalaris with special morphology by scanning electron microscopy.

Laboratory study was conducted on the biology of the phorid fly Megaselia sacalaris. The influence of 3 constant temperatures and various larval densities was researched in the laboratory as these relate to mean life stage rate of development and survival. Flay development on a synthetic diet at 25 degrees C. 75=2% RH and 18 hr photophase was used as the standard. Mean times for development and survival were egg incubation 16.3 h (97.6%); larval period 7.3 days (97.6%); pupal period 9.8 days (95.8%, 91.6%); adult longevity 29.9 days, 24.8 days. Fecundity was 664.8 eggs. One generation required 19.7 days. Data are presented on the influence of 20 degrees C and 15 degrees C on the duration of survival and fecundity life-stages. Theoretical lower thresholds of development for life stages are reported. The adverse effect of larval crowding was reflected at the 100 larvae/10 g diet medium as larval and pupal periods increased. At the 200 larvae/10 g diet medium larval survival declined pupal survival decline began at 100/10 g level. Fecundity was not significant altered. The ultrastructure of the larval stages of M. scalaris was studied by scanning electron microscopy (SEM). Significant changes in morphological features were observed in the anterior and posterior spiracles, but only minimal changes in the labium and mouth-hooks were seen. The ultrastructure of M. scalaris larvae not only provided the chronological transformation of the larval instars, but also can be used to explain their feeding behavior and mode of respiration. Besides, morphological structures useful for specific identification of first and second-instar larvae collected from human corpses may be used in forensic practice.

Animals↗

PubMed2006

Male genotype affects female fitness in a paternally investing species.

Male nutrient provisioning is widespread in insects. Females of some species use male-derived nutrients for increased longevity and reproductive output. Despite much research into the consequences of paternal nutrient investment for male and female fitness, the heritability, and therefore the potential of this trait to respond to selection, has rarely been examined. Males of several butterfly species provide the female with nutrients in the spermatophore at mating. Females of the green-veined white butterfly Pieris napi (Lepidoptera: Pieridae) use male donations both for developing eggs (resulting in higher lifetime fecundity of multiply mated females), but also for their somatic maintenance (increasing longevity). Using half-sib, father-son regression and full-sib analyses, I showed that paternal nutrient investment is heritable, both in terms of the absolute but also the relative size of the spermatophore (controlling for body size). Male size and spermatophore size were also genetically correlated. Furthermore, a separate study showed male genotype had a significant effect on female longevity and lifetime fecundity. In contrast, male genotype had no influence on the immediate egg-laying rate of females following mating, suggesting limited scope for male manipulation of immediate female oviposition. These results indicate that females may derive both direct (increased lifetime fecundity and longevity) and indirect (sons with greater reproductive success) fitness benefits from paternal nutrient donations in this species.

Animals↗

PubMed1989

Intrauterine insemination and ovulation stimulation as treatment of infertility.

Fecundity rates were measured for 302 patient-couples in 991 cycles of intrauterine insemination (IUI) between January 1984 and December 1986 in terms of the diagnoses and whether human menopausal gonadotropin (hMG) was also employed. Those rates were compared with the fecundity rates in 255 of the couples followed in 2,668 untreated cycles. IUI was most beneficial for cervical factor infertility, with a monthly yield of 0.11 in conjunction with hMG and for poor postcoital tests in general but was less impressive when seminal parameters were abnormal. The addition of hMG when ovulation was normal (as an independent variable) did not yield results statistically superior to those of IUI alone (fecundity = 0.06 versus 0.03), but the addition of hMG to the regimen gave an improvement over IUI alone when endometriosis had been diagnosed and in the presence of cervical factor infertility. One serious side effect of therapy was a pelvic abscess, which required hospitalization but not surgery.

Adult↗

PubMedDate not supplied

Hysteroscopic treatment of uterine septum.

Authors report their 4 years experience in the treatment of uterine septum by hysteroscopic metroplasty. 35 patients underwent procedure; no complications occurred. Postoperative reproductive outcome was evaluated in 29 women with follow-up longer than 6 months. Patients were divided into 2 groups according to presence or absence of associated factors compromising fertility. Group A composed of 19 women in which uterine septum was the only cause of pregnancy wastage. Preoperatively they had 40 pregnancies all ending in spontaneous abortion. Postoperatively 15 (79%) patients conceived and 13 (68%) had a live baby. Totally they had 18 pregnancies, 2 (12%) ended in abortion, 1 in molar pregnancy, 1 in premature delivery, 11 delivered at term and 3 are currently beyond 20 weeks pregnant, for a live birth rate of 78%. Life table analysis showed an estimated pregnancy rate of 82% at 12 months, monthly fecundability was 0.13. Group B composed of 10 women in which other factors compromising fertility were present. Preoperatively only 5 experienced pregnancy. Totally they had 8 pregnancies 7 (86%) of which ended in abortions and one in extrauterine pregnancy. Postoperatively only 3 (30%) had pregnancy and all had a live baby. Totally they had 4 pregnancies, 1 ended in abortion and 3 at term for a live birth rate of 75%. Life table analysis showed an estimated pregnancy rate of 11% at 12 months, monthly fecundability rate was 0.01. Hysteroscopic metroplasty proved to be safe and effective for solving pregnancy wastage caused by uterine septum. If other factors compromising fertility were present metroplasty did not increase fecundability, but improved live birth rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Habitual↗

PubMed1989

The effects of single and repeated inoculations of various larval doses on Strongyloides ratti burden and distribution in rats.

The changes in worm burden, distribution, length, and fecundity after and during single and repeated inoculations of 10, 50, or 500 larvae of Strongyloides ratti were examined in rats. Worm burden after a single inoculation of a higher larval dose reduced rapidly. Repeated inoculations of lower larval doses at weekly intervals led to a delayed peak and slower reduction of worm burden; the repeated inoculations of 10 larvae did not induce worm expulsion for at least 7 wk. In repeated inoculations at 3-wk intervals, a primary inoculation of 500 larvae induced strong resistance to reinfection at week 3, whereas no resistance was induced until week 6 in rats receiving repeated inoculations of 10 or 50 larvae. Similar dose-dependent reductions in worm length and fecundity were observed in single and repeated inoculations, and the reductions began earlier than worm expulsion. Intestinal migration of worms from the upper small intestine to the large intestine was observed during the course of single and repeated inoculations. Earlier and clearer migration was observed in rats receiving higher doses. These findings indicate that in S. ratti infection, the changes of worm burden, distribution, length, and fecundity are dependent on the inoculated larval dose.

Animals↗

PubMed1988

In vivo and in vitro egg production by Nematospiroides dubius during primary and challenge infections in resistant and susceptible strains of mice.

Experiments were conducted to examine adult worm burdens, fecal egg output, and in vitro fecundity of Nematospiroides dubius in resistant LAF1 and susceptible CBA mice 12, 15, 18, and 21 days following primary and challenge infections. A strong correlation was obtained on the number of eggs produced by worms cultured in vitro and the egg production as assessed by fecal egg count. Worm counts, fecal egg counts, and in vitro fecundity were similar on all days studied following a primary infection in both mouse strains. However, after challenge infection, LAF1 mice showed lower worm burdens, fecal egg output, and in vitro egg production when compared to CBA mice. Although the egg production of surviving female worms from immune LAF1 mice was decreased, it never fell below a threshold of 100 eggs/day. The reduced fecundity may be a manifestation of a general anti-worm response rather than responses directed specifically at worm reproduction.

Animals↗

PubMed1987

[Inversion polymorphism in the malaria mosquito Anopheles messeae. VII. Fertility and the population genetics structure of the species].

The role of chromosomal inversional complexes of different fecundity has been studied in the process of formation of karyotypic populational structure. Females with homozygotes 2R11 and "north-est" inversional combinations are shown to have maximal total egg production, while females with three or four inversional heterozygotes from XL01, XL12, 2R01, 3R01 and 3L01 demonstrated lower level of fecundity. It is found that the seasonal conversion from r-selection to K-selection occurs in the period of population "prosperity" (July). The results of such conversion are destruction of "northest" genocomplexes and reduction of relative fecundity of inversional homozygotes 2R11-Alternative tendencies take place at the beginning of the reproductive period.

Animals↗

PubMed1987

A comparison of three geographical isolates of Trichinella spiralis from the mid-Atlantic United States.

Three isolates of Trichinella spiralis (black bear: 41o50'N, 79o00'W, 1982; grey fox: 41o00'N, 76o00'W, 1982; domestic pig: 39o80'N, 75o30'W, 1983) from the mid-Atlantic United States were characterized in Crl: COBS CFW (SW) mice during 10 successive 40-day generations. Over 10 generations, the isolates differed as follows: worm position of the ursine isolate was significantly more posteriad compared to the porcine isolate; sex ratio of the vulpine isolate was significantly lower compared to the ursine and porcine isolates; females of the porcine isolate produced significantly more newborn larvae in vitro than the sylvatic isolates; both the larvae per gram (LPG) and reproductive capacity index (RCI) were significantly higher for the porcine isolate; and male worms of the vulpine isolate were significantly smaller than those of the porcine or ursine isolates. No differences were observed among isolates for percentage of inoculum recovered, length of female worms, or uterine length. The fecundity of the isolates in hamsters, gerbils, multimammate rats, Sprague-Dawley rats, and Peromyscus sp. was examined also. Based upon RCI and LPG, the porcine isolate was the most fecund in all hosts except gerbils. This higher fecundity was often manifest as increased morbidity and mortality in hosts infected with this isolate. The relationship between the virulent nature of the porcine isolate and the enhanced transmission of T. spiralis are discussed.

Animals↗

PubMed1986

Dermatopathology and immunity in experimental Psoroptes ovis (Acari:Psoroptidae) infestation of naive and previously exposed Hereford cattle.

Naive and previously exposed young Hereford cattle were infested with Psoroptes ovis and maintained in stanchions for 7 weeks. Skin biopsy samples were examined at 1, 2, 5, and 7 weeks after infestation was induced, compared with those from noninfested control calves, and correlated with changes in the mite populations and development of dermatitis. Gross and microscopic appearance of lesions were qualitatively similar in both groups of infested calves. The lesions occurred early in the previously exposed calves, but progressed slowly, whereas lesions in the naive calves appeared later, but were rapidly progressive. The basic histopathologic pattern was chronic exudative superficial perivascular dermatitis compatible with allergy. The mite populations on the naive calves revealed exponential growth and high fecundity, and reached high population densities, whereas mite populations on previously exposed calves had low growth rates and low fecundity and reached population densities 100 to 1,000 times less than those on naive calves. Seemingly, there was a hypersensitivity to mite antigens. The hypersensitivity response may have been a mechanism by which humoral immunity was delivered to the mite microenvironment and may have contributed to acquired resistance by controlling mite populations. The mechanism of population control seems to be related partially to decreased fecundity of female P ovis.

Animals↗

PubMed1986

Insemination with fresh donor semen.

Factors influencing the probability of conception after artificial insemination with donor semen were investigated in a series of 80 infertile couples. Overall, 46 pregnancies were achieved for a crude pregnancy rate of 58%. Life table analysis showed a cumulative probability of conception of 97.1% at the end of 12 cycles and an average fecundability of 15.1%. These results were achieved using a single insemination per cycle and individualizing the day of insemination based on the woman's basal body temperature. Women who had been pregnant previously had a significantly better fecundability than nulligravid women (P less than .05). The overall rates of conception in those women who required therapy for ovulatory dysfunction were the same as normal women although the fecundability was somewhat lower. Women who had abdominal pathology had an overall conception rate of 23%.

Cervix Mucus↗

PubMed1967

Mathematical simulation of an aquatic snail population.

Techniques for controlling the intermediate snail hosts of schistosomiasis have had to be evaluated by field trials, since the complexity of snail population dynamics has so far made it impossible to predict the effects of these techniques and thereby avoid costly field testing.However, in laboratory studies with Biomphalaria glabrata it was found that the fecundity of these snails was directly proportional to F/NV, where F is the total amount of food in the habitat, N the number of snails, and V the volume of the habitat. The use of this fecundity variable together with data published on snail longevity and fecundity made it possible to construct a mathematical model of a snail population which may eventually be useful for evaluating snail control methods.For preliminary verification of the model, its predictions were compared with a published history of a population of Bulinus globosus in a small pond. The general agreement of the predicted and observed population data indicated that the basic structure of the model was sound.

Animals↗