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PubMed1991

Probabilistic analysis of fertility and fecundity: an application to Tombia in Rivers State of Nigeria.

"This paper discusses fertility and fecundity from a probablistic point of view, using Tombia [Nigeria] as a case study. The fertility distribution in Tombia, fertility beyond a given time, infertility rate, measures of central tendencies and dispersion of the fertility distribution in Tombia, prediction of age at menopause in Tombia and projection of fertility beyond a given time are discussed. The emphasis is on the discussion and interpretation of the results obtained in the probabilistic models developed therein."

Africa↗
PubMed1993

Estimation of fecundity and secondary sterility from survey data on birth intervals in Egypt.

Data on the last closed and open birth intervals have been used to ascertain the current potential of childbearing for women in terms of estimating fecundity and secondary sterility by age, residence, and educational subgroup. Under the assumption that after a specific period from the last birth a certain proportion of women become secondarily sterile, we propose and apply an inflated model of open birth interval to obtain the proportion of women who are secondarily sterile. The data used for the analysis are extracted from the Egyptian Fertility Survey conducted in 1980.

Adolescent↗
PubMed1998

Non-genetic benefits of mate choice: fecundity enhancement and sexy sons.

I compared reproductive success (lifetime number of fertilized eggs) as a function of mate choice among females of the stink bug, Nezara viridula L. (Hemiptera: Pentatomidae). 'Choosing' (C) females were placed with one of two males on alternate days. CI females chose between inexperienced males while CR females chose between males previously rejected by CI females. 'Non-choosing' (N) females were placed with the same male every day. Non-choosing NI, NR and NA females encountered, respectively, inexperienced males, previously rejected males, or previously accepted and mated males. Reproductive success was highest for CI females, showing direct selection on mate preferences. Reproductive success did not differ between CR and NR females, indicating that male quality, not the act of choosing a mate, affects fitness. CI females preferred males with longer antennae and their fecundity (lifetime number of eggs) was correlated with male antenna length, consistent with antenna length as an indicator of male ability to transfer nutritive sperm produced in paired harlequin lobes of the testes. Harlequin lobes were smaller in rejected than chosen males. In second-generation mate choice trials, sons of NR females competed well against sons of NA females but not against sons of CI females. This suggests that non-genetic paternal contributions that decline with prior mating account for the attractiveness of sons because sons of CI and NA females shared the same fathers. Sons experiencing mating success came from larger eggs and egg size was greatest for CI females, perhaps as a consequence of paternal nutritional contributions. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1998

Handicap signalling: when fecundity and viability do not add up.

It is widely accepted that a requirement for honest handicap signalling is that higher-quality signallers pay lower marginal costs for advertising. This is a simple, powerful principle, but it is correct only if the fitness effects of fecundity and viability are strictly additive. Additivity would not be expected from most life history models. The general criterion for honest handicap signalling is that higher-quality signallers must have higher marginal fitness effects of advertising. This might result from higher benefits rather than lower costs. The general criterion implies the existence of a ridge on the fitness surface for two correlated characters, quality (or viability) and advertising. This has important implications for the design of experiments. Critical tests of the handicap hypothesis should establish that signallers of different quality are on a rising fitness ridge because of different cost-benefit trade-offs. The further question of whether receivers are maximizing their fitness requires additional experiments because handicap signalling does not require that the receivers maximize their fitness, only that they return benefits to signallers as an increasing function of the size of the signal. If receiver preferences are exaggerated by sensory bias or indirect selection, the resulting exaggerated signals may be consistent with the handicap principle. Copyright 1998 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1994

Vaccination of sheep with purified cysteine proteinases of Fasciola hepatica decreases worm fecundity.

There has been some evidence from several parasite systems that proteinases might have potential as protective antigens against parasitic infection. A cysteine proteinase complex identified in the regurgitant of adult F. hepatica was examined in this context. The thiol-cathepsin-related proteinases of M(r) 28,000 were purified and tested in vaccine trials of sheep infected with liver fluke. Ten animals were immunised with the purified proteinases and developed antibodies to the cysteine proteinases prior to challenge with F. hepatica metacercariae. Infection appeared to cause a boost in antibody response by Week 4 into infection, and antibody levels were generally sustained throughout infection. The cysteine proteinases are not novel antigens, since low-level antibody titres were also detected in nonimmunised controls by late infection. On completion of the trial, there was no difference in worm burden between the two groups. However, faecal egg counts and therefore worm fecundity were significantly decreased.

Animals↗
PubMed1996

On the heterogeneity of fecundability.

We propose to use a general mixing distribution in modeling the heterogeneity of the fecundability of couples. We introduce a sequence of parameters called canonical moments, which is in one to one correspondence with the moments, to characterize the mixing distribution. By using the bootstrap method, we can estimate the standard errors of our estimates. Our method modifies the usual moment estimates so that the resulting mixing distribution is always supported on [0, 1]. Moreover, the downward bias of the moment estimate of the number of support points would be reduced. Our approach can be used for censored data. The application of our technique in finding the sterile subpopulation is also discussed. The theory is illustrated with several data examples and simulations.

Biometry↗
PubMed1988

Harvesting under density-dependent mortality and fecundity.

The problem of optimal harvesting in equilibrium is considered in a Leslie matrix model in which both mortality and fecundity in all age-classes may be density-dependent. The conclusion is that the optimal strategy is of the two-age-class type, in common with results obtained previously for simpler models.

Fertility↗
PubMed1987

Fecundity and localization of Dipetalonema viteae (Nematoda, Filarioidea) in the jird Meriones unguiculatus.

In quantitatively infected Meriones unguiculatus autopsied during prepatency, the embryonic development of fertilized eggs in the uteri of female Dipetalonema viteae commenced 29-32 days p.i., and approximately 20 days later the first microfilariae were released. In host animals examined at the onset of patency 45-59 days p.i. the average adult recovery rate was 31%. The worms were localized in the subcutaneous tissue (65.3%), fasciae of muscles (26.9%) and body cavities (7.8%). Female worms from the peritoneal and pleural cavities were significantly longer (44.3 +/- 10.4 mm) than those from the other habitats (33.7 +/- 5.5 mm). Female worms 14-20 weeks p.i. contained a total of 172,700 +/- 62,400 intrauterine stages, 21% of them pathologically altered. Based on these parameters, the expected in vivo fecundity of a female worm was calculated as about 7000 microfilariae per day.

Animals↗
PubMed1986

Fecundity of Litomosoides carinii (Nematoda, Filarioidea) in vivo and in vitro.

Several parameters concerning the reproduction of Litomosoides carinii were assessed using quantitatively infected cotton rats (Sigmodon hispidus). The course of embryogenesis from the fertilization of eggs to the delivery of the first microfilariae was observed by daily autopsies during prepatency. The duration of embryogenesis in vivo could thus be determined as 18 +/- 2 days. The contents of embryos in the uteri of female worms had been examined at various intervals. At the onset of patency 7-8 weeks p.i. the females were 71 +/- 6 mm long and on average contained 308 X 10(3) embryos/female, of which 19% were pathologically altered. In the middle of patency 16-20 weeks p.i. the females had grown up to 100 +/- 11 mm in length and now contained 509 X 10(3) embryos/female, 25% of them were pathologically altered, the others were normally developed. A positive correlation between the body length of a female worm and its number of embryos in utero was evident. Additionally the percentage of pathologically altered embryos was increased with respect to the age of the worms. The calculated fecundity of a female L. carinii in vivo of around 20 X 10(3) microfilariae/female per day had been confirmed with worms maintained in vitro. Three combinations of media and serum supplements were used and their influence on embryogenesis evaluated.

Animals↗
PubMed1995

An acute dose of monosodium L-glutamate causes decreased fecundity and enhanced loss of the cestode Hymenolepis diminuta from rats.

A method for the rapid quantitative analysis of eggs in the feces of rats infested with Hymenolepis diminuta is described. In one experiment, eggs in the feces of individual rats were monitored for 8 days. Rats were provided with 1 ml saline vehicle or with 0.1 or 1 g monosodium glutamate (MSG) by stomach tube and egg production was monitored. Egg production decreased in saline vehicle-treated rats, but the decrease was significantly greater in the group treated with 1 g MSG. There was no significant change in fecal mass output from rats with different treatments. The number of worms harbored by rats treated with 1 g MSG was significantly lower than those of saline control-treated rats. In another experiment, neither anesthesia alone nor anesthesia with 1 g sucrose significantly reduced egg output as compared with that observed in untreated rats. Therefore, MSG has a significant negative effect on both the fecundity of H. diminuta and the numbers of worms harbored by rats.

Animals↗
PubMed1986

The effect of avermectins on feeding, salivary fluid secretion, and fecundity in some ixodid ticks.

We tested the effects of the potent acaricides, avermectin B1a (AVM) and 22,23-dihydroavermectin B1 (ivermectin; IVM) when injected directly into partially fed and fully engorged female ticks. When injected into small ticks (Amblyomma hebraeum Koch), neither drug (up to 100 micrograms/kg b.w.) inhibited subsequent engorgement nor affected oviposition latency, weight of total egg mass laid nor viability of laid eggs. At higher concentrations (1000 and 5000 micrograms/kg b.w.), AVM and IVM were markedly toxic. When injected into engorged ticks, both drugs increased oviposition latency, and reduced fecundity at about 75-100 micrograms/kg b.w. Vitellogenesis, as assessed by a spectrophotometric assay of the ovaries, was not inhibited. Also at 50-100 micrograms/kg b.w., AVM and IVM caused paralysis of the abdominal dorso-ventral muscles and the leg muscles. Both drugs, at 7 days post-injection, proved detrimental to salivary gland function in both small and large ticks, but had little effect on salivary gland weight. At concentrations which did not inhibit oviposition (20-50 micrograms/kg b.w.) many of the eggs dried out even though they were kept at high RH. We then demonstrated in Amblyomma americanum, Dermacentor andersoni and D. albipictus that removal of egg wax (by extraction with hexane) induced a marked increase in water permeability. IVM neither increased water permeability of D. andersoni eggs nor diminished the amount of egg wax deposited on the surface of the eggs, when injected posteriorly through the alloscutum. However, injection of IVM, dimethylsulphoxide (vehicle for IVM) or distilled water through the articulation between the capitulum and scutum ('anterior injection'), did markedly reduce the wax coating and increased egg permeability. We suggest that anterior injection damages Gené's organ and thus causes the latter effects.

Animals↗
PubMed2002

Cocoon production, morphology, hatching pattern and fecundity in seven tropical earthworm species - a laboratory-based investigation.

Data on the reproductive biology of seven Indian species of earthworms, viz. Perionyx excavatus Perrier, Lampito mauritii Kinberg, Polypheretima elongata (Perrier), Pontoscolex corethrurus (Muller), Eutyphoeus gammiei (Beddard), Dichogaster modiglianii (Rosa) and Drawida nepalensis Michaelsen are presented. The peregrine earthworms such as Perionyx excavatus, Pontoscolex corethrurus, Dichogaster modiglianii, and Polypheretima elongata are considered to be continuous breeders with high fecundity. Native Lampito mauritii and Drawida nepalensis are semi-continuous and Eutyphoeus gammiei discrete breeders. There is a dramatic increase in cocoon production by most earthworm species of Tripura in the summer and monsoon with a corresponding peak during April and July. Cocoon production decreased or ceased during winter. Temperature affected the incubation period of cocoons. With increase in temperature, incubation period increased in the endogeic worms, Pontoscolex corethrurus, Polypheretima elongata and Drawida nepalensis and decreased in the epigeic worms, Perionyx excavatus and Dichogaster modiglianii, within a temperature range between 28-32 degrees C under laboratory conditions. There was a significant (P < 0.05) positive correlation between number of hatchlings per cocoon and incubation period in Lampito mauritii. High rate of cocoon production, short development time with high hatching success, as well as continuous breeding strategies in the epigeic species Perionyx excavatus and Dichogaster modiglianii and the top soil endogeic species, Pontoscolex corethrurus, Drawida nepalensis and Lampito mauritii, indicate their possible usefulness in vermiculture. The giant anecic worm, Eutyphoeus gammiei, which has a very long cocoon development time, discrete breeding strategy and very low rate of cocoon production, is not a suitable species for vermiculture.

Animals↗
PubMed2000

Female bushcrickets mated with parasitized males show rapid remating and reduced fecundity (Orthoptera: Phaneropteridae: Poecilimon mariannae).

Following mating, female bushcrickets undergo a refractory period during which they are sexually unreceptive. The length of the refractory period correlates with the size of the spermatophylax. However, the size of the nuptial gift of acoustically signalling bushcrickets is often reduced as a result of infections by parasitoid flies. We examined the effect of male parasitoid infection on the induction of the refractory period and fecundity of females. We found a drastically reduced refractory period in females if the first mating partner was infected. During this shortened period fewer eggs were deposited, as an effect of the shorter refractory period, whereas the daily egg-laying rate remained the same regardless of whether the females were mated with a parasitized or an unparasitized male.

Acoustic Stimulation↗
PubMed2004

Development of a highly fecund inbred strain of mice.

A highly fecund inbred mouse line has been established from the Quackenbush Swiss (QS) outbred strain by full-sib inbreeding combined with selection for high number of pups born alive (NBA) and low interlitter interval (ILI). After more than 50 generations of inbreeding and selection, this line, named QSi5, has an NBA of 13.4 and an ILI of 29 days, averaged over the first four parities, and a total productivity of 50.7 NBA. With its exceptional reproductive performance, this line will be very useful in the creation of resources (including advanced intercross lines) for analysis of quantitative trait loci for a wide range of traits, and for the cost-effective creation of congenic lines.

Animals↗
PubMed2002

Fecundity and morbidity following acute pelvic inflammatory disease treated with doxycycline and metronidazole.

We studied fecundity and late sequelae of 39 women who had laparoscopic and microbiological sampling-proven acute pelvic inflammatory disease (PID) treated with the same antimicrobial regimen. The grade and etiology of index PID were classified using laparoscopy, endometrial biopsy and microbiological cultures from the cervix, endometrium and tubes: 20 had mild and 19 severe PID. The mean (SD) follow-up period after the index PID was 125 (44) [range 8-204] months. The primary end-point was pregnancy. All other or recurrent infections or other diseases related to the infection, including infertility, were evaluated. Twenty (51%) women had laparotomy or second laparoscopy during follow-up and findings were evaluated. Chlamydia trachomatis was isolated in 38% of all cases. Eleven (28%) of 39 women avoided conception or it was no longer possible. Twenty-eight women had tried to conceive after the index PID and 25 (89%) of them had at least one pregnancy. Twenty-five women had 56 pregnancies, 33 (59%) of which ended in delivery, 9 (16%) miscarried, 13 (23%) were induced abortion and only one (1.8%) tubal pregnancy occurred. Etiologic factors or severity of PID made no difference to the conception rate. Patients with mild or moderate salpingitis had a high conception rate. Endometriosis was found in 6 (30%) out of 20 women with second laparoscopy or laparotomy. Hysterectomy had been performed in 4 cases. Precise diagnosis of acute PID is the cornerstone for the treatment of the condition. Combination regimens, including drugs against the most common factors underlying acute PID against both aerobic and anaerobic microbes, prevent late sequelae in cases with mild or moderate salpingitis but not in cases with tubal or pelvic abscess.

Abortion, Induced↗
PubMed2006

Effects of telomere length in Drosophila melanogaster on life span, fecundity, and fertility.

Chromosome length in Drosophila is maintained by targeted transposition of three non-long terminal repeat retrotransposons, HeT-A, TART, and TAHRE, to the chromosome ends. The length and composition of these retrotransposon arrays can vary significantly between chromosome tips and between fly stocks, but the significance and consequences of these length differences are not understood. A dominant genetic factor, Tel, has been described, which causes a severalfold elongation of the retrotransposon arrays at all telomeres. We used this strain to assess possible affects of extended telomeres on the organism. While we found no effect on life span of the adults, we could demonstrate a correlation between long telomeres and reduced fertility and fecundity in individual females, which is also reflected in abnormal oocyte development.

Animals↗