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PubMed2002

Pupal mass and wing length as indicators of fecundity in Aedes albopictus and Aedes geniculatus (Diptera: Culicidae).

Many studies investigating the ecology and evolution of mosquitoes rely on morphometric measurements related to body size to estimate fecundity. Determining the most reliable estimators of fecundity is therefore an important methodological consideration. We compared the relative accuracy of pupal mass and wing length in predicting the fecundity (number of mature stage IV follicles of the first gonotrophic cycle) for (1) Aedes albopictus (Skuse) reared in the laboratory, (2) Aedes geniculatus (Oliver) reared in the laboratory, and (3) A. geniculatus that completed their larval development in water-filled tree holes (their natural habitat) in the field. In all cases, pupal weight and wing length provided highly significant and equally accurate indicators of fecundity. Furthermore, the measurement error (1 - repeatability) for both traits was < or = 1%. Our results indicate that either pupal mass or wing length can be used with confidence to predict fecundity in these two aedine mosquitoes.

Aedes↗
PubMed2000

The relationship between size and fecundity in Aedes albopictus.

Recent use of correlates of the intrinsic rate of increase and models to study population dynamics in mosquitoes has emphasized the need for species specific data on the relationship of morphological factors such as body size to life history parameters such as fecundity. Aedes albopictus is of concern because of its continued spread and population growth in the U.S. and the potential for virus transmission. We examined the relationships between pupal wet weight and adult female wing length and between female wing length and fecundity in the first gonotrophic cycle in U.S. strains of Ae. albopictus. There was a significant positive relationship between pupal wet weight and adult wing length. The relationship between wing length and fecundity was also significant and positive, but with lower correlation coefficients and higher variance indicating that other factors also affect fecundity. The regression coefficients for the fecundity-wing length equation did not differ between two strains of Ae. albopictus.

Aedes↗
PubMed1992

Abnormal findings on hysterosalpingography: effects on fecundity in a donor insemination program using frozen semen.

OBJECTIVE: We sought to evaluate the effect of abnormal baseline hysterosalpingography (HSG) on subsequent fecundity during the first six cycles of treatment. METHODS: Hysterosalpingography was performed on 208 asymptomatic ovulatory women with no history of pelvic disease who were referred for donor insemination. The findings were categorized into five groups: 1) normal study, 2) uterine anomaly or filling defect with bilateral tubal patency, 3) normal uterine anatomy with unilateral tubal patency, 4) normal uterine anatomy with bilateral tubal blockage, and 5) normal uterine anatomy with hydrosalpinx. Subjects in groups 4 and 5 received inseminations only if patency of at least one fallopian tube was demonstrated with laparoscopy. Life-table analysis was performed to calculate the average monthly fecundity and cumulative conception rates for each group. The Mantel-Haenszel test was used to compare group fecundities. RESULTS: A total of 1460 donor insemination cycles were performed. The number of cycles in each group were as follows: group 1, 1173 (80%); group 2, 153 (10%); group 3, 90 (6.2%); group 4, 16 (1.1%); and group 5, 28 (1.9%). None of the patients in group 4 or 5 conceived. The cumulative conception rates in the first three groups were 46, 34, and 40%, respectively, and were not significantly different from one another (P greater than .05). Although a high incidence of uterine filling defects and unilateral tubal blockage was observed (19.2%), the incidence of an abnormal HSG finding that significantly decreased fecundity was only 2.8%. CONCLUSION: In women with no history of tubal or uterine disease, routine HSG before initiation of donor insemination is of limited value for identifying decreased treatment fecundity.

Adult↗
PubMed1992

Relationship of follicle number and other factors to fecundability and multiple pregnancy in clomiphene citrate-induced intrauterine insemination cycles.

OBJECTIVE: To determine characteristics associated with pregnancy and multiple gestation after clomiphene citrate (CC)-intrauterine insemination (IUI). DESIGN: Prospective study of all patients undergoing CC-IUI between January 1, 1983 and December 31, 1989. SETTING: Private fertility clinic. PATIENTS: Eight hundred forty-nine patients undergoing 1,974 cycles of CC-IUI. MAIN OUTCOME MEASURES: Relationship between number and size of preovulatory follicles, age, additional infertility diagnosis, medication, and initial semen quality to fecundity, birth, and multiple gestation. RESULTS: Uncorrected, per cycle fecundity was 7.2%. The number of follicles greater than or equal to 12 mm (r = 0.055, P less than 0.05) was and the number greater than or equal to 15, 18, and 21 mm was not correlated with fecundity. Endometriosis with (P = 0.013) or without (P less than 0.0005) tubal adhesions and tubal adhesions alone (P = 0.005), decreased fecundability by 50%. Initial semen quality did not affect fecundity, unless semen concentration was less than 5 x 10(6)/mL or motility was less than 20%. Multiple pregnancy was not associated with the dose of CC, use of human chorionic gonadotropin, or number of follicles. CONCLUSIONS: Multiple pregnancy was unrelated to follicle numbers or to CC dose. The highest birth rates after CC-IUI occurred when initial sperm concentration was greater than or equal to 5 x 10(6)/mL, motility was greater than or equal to 20%, and no endometriosis or adhesions were present.

Clomiphene↗
PubMed1991

The effect of age on female fecundity.

To determine the relationship between age and female fecundity, 210 women were studied prospectively. The subjects had negative infertility evaluations and were receiving therapeutic donor insemination. Life-table analysis was performed on 751 donor insemination cycles. For comparison, patients were divided into five separate age groups and into two separate groups, ages 19-34 and 35-45. Monthly fecundity and cumulative conception rates were calculated for each group. A significant difference was found when all age groups were compared (P = .05) and when those at or above age 35 and those below age 35 were compared (P less than .05). Frozen semen was used in 92% of all cycles. The average monthly fecundity of all patients treated with frozen semen was 16%. This study confirms a progressive decline in fecundity with age in a completely evaluated group of women undergoing therapeutic donor insemination and demonstrates that frozen semen can yield acceptable fecundity provided sufficient numbers of motile sperm are used for each procedure.

Adult↗
PubMed1978

Effects of various factors on selection for family planning status and natural fecundability: a simulation study.

The effect of various factors on selection for family planning status and for natural fecundability is studied in a simulation that incorporates a beta distribution of fecundability among women. The mean fecundabilities of current spacers, current limiters, current nonusers, and pregnant women are compared. These ratios are influenced by duration of marriage and by desired number of children. Effects of different levels of contraception are measured. Another strategy, spacing the last two wanted births, is also studied. It is found that breast-feeding status has little effect on fecundability selection. The women usually found to have greatest fecundability are not those recently pregnant at durations of marriage five and ten years, unless they wanted fewer than two children, but rather those who are using contraception to limit the number of children.

Adult↗
PubMed1984

The effect of experimental Onchocerca infections on the fecundity and oviposition of laboratory reared Simulium sp. (Diptera, Simuliidae).

Two species of Simulium were used to examine the effect of experimental Onchocerca lienalis infections on their fecundity and oviposition rates. S. ornatum s.l. was chosen as a natural vector of bovine onchocerciasis in Britain, and S. lineatum was selected because of its suitability as an experimental model for oviposition studies. Infection was either by feeding with blood containing microfilariae, or by intrathoracic injection of the parasites. Using the blood feeding technique, reductions in the fecundity of S. lineatum were observed at rates of 21 to 76%, depending on the concentration of parasites. A reduction of 21% in the fecundity of S. ornatum s.l. (P less than 0.05) was achieved when flies were fed on microfilariae at 69,000 per ml. Although individual flies feeding on infected blood may take as much as those in control groups, the feeding rates were reduced in several instances. S. lineatum also showed a depression of oviposition rate when infected by O. linenalis larvae. Fecundity was also significantly reduced when the route of infection was intrathoracic. Reductions for S. lineatum depended on the inoculum, but were either 36% (10 microfilariae per fly) or 54% (50 microfilariae per fly). S. ornatum s.l. showed a 13% reduction in fecundity when given 20 microfilariae per fly. It was concluded that similar experimental studies could be usefully performed with S. damnosum s.l. infected with O. volvulus microfilariae.

Animals↗
PubMed1982

The effects of cortisone on fecundity, number, and distribution of adult Trichinella spiralis and on trichinous enteritis in the host.

The effects of cortisone on fecundity, distribution, and numbers of adult Trichinella spiralis and on enteritis in the host were compared in mice receiving different numbers of larvae. As the amount of cortisone given to mice was increased enteritis decreased, and fecundity of adult worms increased. Injection of mice with cortisone caused retention of a greater percentage of adult worms in the anterior regions of the host small bowel than in uninjected mice. By day 11 PI, when adult worms in cortisone-injected mice were more widely distributed along the host small intestine, fecundity of adult worms isolated from mice receiving more worms (500, 1,000, or 2,000 worms) attained levels previously seen only in worms from mice infected with 250 T. spiralis. The extended longevity of adult worms in cortisone-injected mice was accompanied by a severe reduction in fecundity after day 11 PI. Addition of cortisone to the culture medium at concentrations above 0.1 mg% was accompanied by a reduction in fecundity of adult worms.

Animals↗
PubMedDate not supplied

Puberty and the family formation process in Sudan: age-at-menarche differential fecundity hypothesis revisited.

This paper revisits and extends an inquiry on the age-at-menarche differential fecundity hypothesis. Earlier studies have interpreted the difference in the onset of female pubertal maturation as indicative of biological differences in fecundity between early and late menarcheal women. Using the WFS data for Sudan, the authors address the entire reproductive life of the women in terms of their transition from one parity to the next, as well as the speed with which birth intervals are closed, as a way to infer biological fecundity among the women. The study concludes that there is little evidence that early menarcheal women are more fecund than their late puberty counterparts.

Adult↗
PubMed2006

Nonadditive effects of flower damage and hummingbird pollination on the fecundity of Mimulus luteus.

Flower herbivory and pollination have been described as interactive processes that influence each other in their effects on plant reproductive success. Few studies, however, have so far examined their joint effects in natural populations. In this paper we evaluate the influence of flower damage and pollination by the hummingbird Oreotrochilus leucopleurus on the fecundity of the Andean monkey flower Mimulus luteus. We performed a 2x2 factorial experiment, with artificial clipping of lower petals and selective exclusion of the hummingbird as main factors. In spite of the relatively low proportion (27.5%) of the variance in seed production accounted for by the full factorial model, artificial damage and hummingbird exclusion, as well as their interaction, were highly significant, indicating nonadditive effects of factors on plant fecundity. In the presence of hummingbirds, undamaged flowers had a seed production that was 1.7-fold higher than for damaged flowers, suggesting that the effect of flower damage on female reproductive success occurs probably as a consequence of hummingbird discrimination against damaged corollas. This result indicates that the impact of flower herbivory on plant fecundity was contingent on the presence or absence of hummingbirds, suggesting that pollinators may indirectly select for undamaged and probably resistant flower phenotypes. A second interaction effect revealed that undamaged flowers produced 78.5% more seeds in the absence of rather than in the presence of O. leucopleurus, raising the question of the ecological mechanism involved. We suggest that the strong territorial behavior exhibited by the bee Centris nigerrima may confine the foraging activities of the remaining bee species to safe sites within exclosures. Overall, our results provide evidence that hummingbird pollination and flower herbivory have interdependent effects on M. luteus fecundity, which indicates that it will be difficult to predict their ecological and evolutionary consequences unless interactions are analyzed in an integrated form.

Animals↗
PubMed2006

Nonylphenol stimulates fecundity but not population growth rate (lambda) of Folsomia candida.

The toxicity of nonylphenol (NP) to springtails was pronounced at 40 mg/kg dry weight soil, at which no animals survived. Body length and fecundity were the individual life-history traits significantly stimulated by sublethal concentrations of NP during a 64-day experiment. However, the effects of NP on these traits did not result in a statistically significant increase in population growth rate (lambda). Decomposition analysis indicated that fecundity was the main contributor to the (non-significant) changes observed in lambda. However, since the elasticity of fecundity was very low, large changes in fecundity resulted in a minimal effect on lambda. Juvenile survival had the highest elasticity of all traits, but was not affected by NP, and therefore did not contribute to effects on lambda. This study confirms previous studies showing that effects of chemicals on individual life-history traits are attenuated at the population level and that lambda is an appropriate endpoint for ecotoxicological studies.

Animals↗
PubMed2006

Environmental contaminant levels and fecundability among non-smoking couples.

OBJECTIVE: To investigate the effects of low level maternal and paternal persistent contaminant exposures on fecundability among couples from the general population. METHODS: About 41 couples having their first pregnancy completed questionnaires and provided blood samples for analysis of metals, organochlorine pesticides, and polychorinated biphenyls. Associations of personal consumption and contaminant measures for mothers, fathers, and couples overall were analyzed through fecundability odds ratios (fOR, probability of pregnancy per month in more versus less exposed) in multivariable analyses. FINDINGS: Couples with higher reported caffeine consumption (couple consumption > or =111 drinks/month, fOR 0.25, 95% CI, 0.10, 0.63) and higher mercury concentrations in maternal blood (>1.2 microg/L or 0.24 ppm in hair, fOR 0.22, 95% CI, 0.07, 0.72) had lower fecundability, after adjustment for intercourse frequency. CONCLUSION: Reduced fecundability at levels below the mercury reference dose warrants further research and prudent reduction in persistent toxic substances exposure among women and men of reproductive age.

Adult↗
PubMed1993

Relationship of endometrial thickness and pattern to fecundity in ovulation induction cycles: effect of clomiphene citrate alone and with human menopausal gonadotropin.

OBJECTIVE: To determine if preovulation endometrial thickness or pattern are related to fecundity and to use of clomiphene citrate (CC) or hMG in IUI. DESIGN: Prospective ultrasound evaluation the day of hCG after CC alone (n = 197), hMG alone (n = 49), concurrent hMG or sequential CC and hMG (n = 205), and no medications (n = 23). SETTING: Private fertility clinic. PATIENTS: Two hundred seventy-one patients undergoing 474 cycles of IUI. MAIN OUTCOME MEASURES: Endometrial thickness, pattern, per cycle fecundity, and continuing pregnancy. RESULTS: Endometrial thickness was related to fecundity and continuing pregnancy. No pregnancies occurred when thickness was < 6 mm. The continuing pregnancy rate was 12.6% when thickness was > or = 9 mm, compared with 6.9% when thickness was 6 mm to 8 mm. Endometrial pattern was unrelated to pregnancy. Average endometrial thickness was decreased when hMG and CC were used in combination (7.9 mm) compared with hMG alone (9.4 mm). Endometrial thickness was negatively related to CC dose and positively related to the day of hCG administration by ANOVA. CONCLUSIONS: Endometrial thickness the day of hCG administration is prognostic of fecundity and continuing pregnancy in cycles of ovulation induction.

Adult↗
PubMed1996

Does cigarette smoking impair natural or assisted fecundity?

OBJECTIVES: To assess the effects of female and male smoking on natural and assisted fecundity. DESIGN: A systematic review of published studies was conducted, identifying reports using on-line and hand search techniques. INCLUDED STUDIES: Potentially relevant articles were screened for inclusion based on the following criteria: comparative study (cohort or case control) with clinical pregnancy or live birth reported among smokers and nonsmokers. EXPOSURE: Cigarette smoking. MAIN OUTCOME MEASURES: Time to conceive; conceptions per subject or per cycle; spontaneous abortion rate. RESULTS: Thirteen relevant studies of natural conception were identified. All but one demonstrated a negative association between smoking and fecundity (odds ratio [OR] for conception or live birth 0.33 to 1.0). Seven studies of IVF-GIFT yielded a common odds ratio for conception of 0.57 (95% confidence interval 0.42 to 0.78). Seven studies evaluating spontaneous abortion suggested a small increased risk among female smokers (OR 0.83 to 1.8). Twenty-one studies assessing smoking in men demonstrated no consistent effect on sperm quality. None of the four studies evaluating fertility in male smokers demonstrated significant impairment. CONCLUSION: This body of literature suggests a small but clinically significant detrimental effect of female smoking on both time to conception and spontaneous abortion risk. Variability between studies, particularly in terms of adjustment for confounding factors, undermines the strength of these conclusions. However, the consistent dose-response effect in both the spontaneous conception and abortion literature and a return to normal fecundity among exsmokers suggest a causal association. The effect of male smoking on fecundity is probably far less significant.

Abortion, Spontaneous↗
PubMed1997

Schistosoma mansoni oviposition in vitro reflects worm fecundity in vivo: individual-, parasite age- and host-dependent variations.

In an attempt to determine whether in vitro oviposition of adult S. mansoni reflects the fecundity status of worms in vivo, Mongolian gerbils and ICR, BALB/c and SCID mice were infected with about 100 cercariae and examined on an individual basis, 5-12 weeks later, for worm burden, counts of eggs in liver and small intestine, and for the rate of egg deposition of ex-vivo female worms cultured in vitro, singly or in pairs, over a 3-5 day incubation period. The percentage of egg-laying female worms and the number of eggs laid/female after 3 days in culture showed, like worm fecundity in vivo, wide inter-worm variability, especially in 5-, 6- and 12-week-old worms; varied significantly with the age of the parasite with a maximum level attained by worms of approximately 8 weeks of age; and differed in worms recovered from different host species and strains. The data taken together indicate that measuring the egg-producing ability of S. mansoni in vitro reflects the fecundity status of worms in vivo and additionally provides likely explanations for hitherto poorly understood findings on schistosome fecundity.

Animals↗
PubMed1997

Fecundity of sealworm (Pseudoterranova decipiens) infecting grey seals (Halichoerus grypus) in the Gulf of St. Lawrence, Canada: lack of density-dependent effects.

Uterine egg counts were determined by means of an electronic particle counter in individual female sealworm, Pseudoterranova decipiens (Nematoda: Ascaridoidea: Anisakidae) collected from grey seals (Halichoerus grypus) from Anticosti Island, northern Gulf of St. Lawrence, in August and September 1992. Mean number of eggs per female was 54,916.9 (+/- 51,866.4), with a maximum of 300,000. Egg counts were strongly correlated with worm length, and less so with host sex and age, sealworm sex ratio, and densities of Anisakis simplex and Phocascaris sp. No effect of sealworm density on worm egg counts was determined and competitive effects by Contracaecum osculatum on sealworm fecundity were not observed. Analyses demonstrated that variation in sealworm fecundity was greater among seal hosts within groups than between groups for host age and sex, density of sealworm, and density of C. osculatum. No evidence for density-dependent regulation of sealworm fecundity could be found. Variations in worm egg counts are attributed to individual host effects on worm growth and fecundity.

Animals↗
PubMed1997

Anti-fecundity immunity to Schistosoma japonicum induced in Chinese water buffaloes (Bos buffelus) after vaccination with recombinant 26 kDa glutathione-S-transferase (reSjc26GST).

We have shown previously that immunisation of mice and pigs with recombinant 26 kDa GST (reSjc26GST) induces a pronounced anti-fecundity effect after experimental infection with Chinese Schistosoma japonicum. We report here that anti-fecundity immunity can also be induced against reSjc26GST in Chinese water buffaloes (Bos buffelus), important reservoir hosts for S. japonicum in China. Anti-Sjc26GST antibodies were produced in immunised buffaloes and, following challenge with S. japonicum cercariae, a 22.3% reduction in worm numbers was evident in vaccinated when compared with control animals. The anti-fecundity effect was characterised by a significant decrease in faecal egg output and eggs deposited in host tissues with those in the liver and intestine being reduced by about 50%. In addition to the anti-fecundity effect, reSjc26GST reduced by nearly 40% the egg-hatching capacity of S. japonicum eggs into viable miracidia. In terms of vaccination strategy, these effects would combine to diminish pathology in animals immunised with reSjc26GST and reduce transmission of schistosomiasis japonica.

Animals↗
PubMed1984

Fecundity-reducing pheromone in Argas (Persicargas) arboreus (Ixodoidea: Argasidae).

Fed adult Argas (Persicargas) arboreus produce a fecundity-reducing pheromone which affects all or most females in crowded conditions. Unfed adults and unfed and fed nymphs do not produce this pheromone. The effect of this pheromone is probably additive, increasing with additional crowding of adults. Mechanical disturbance is excluded as the cause of fecundity reduction. Fed females separated by a perforated barrier from crowded adults also exhibit very low fecundity. Adult excretory materials used 31 days post-feeding do not contain the fecundity-reducing pheromone. Preliminary experiments suggest that this pheromone is spatially limited in action, does not affect gonadotropic hormone synthesis and/or release, and does not induce oviposition deterrence behaviour. This may be considered to be a primer pheromone, causing alteration in normal vitellogenin synthesis and/or uptake and deposition in oocytes. The source and chemical nature of this pheromone should be investigated.

Animals↗