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PubMed2004

Growth, fecundity and sex ratio of adult whaleworm (Anisakis simplex; Nematoda, Ascaridoidea, Anisakidae) in three whale species from the North-East Atlantic.

The growth rate, fecundity, and sex ratio of Anisakis simplex in minke whales (Balaenoptera acutorostrata), porpoises (Phocoena phocoena) and long-finned pilot whales (Globicephala melas) was studied on the basis of material from the North Atlantic. A total of 8,135 mature A. simplex were collected from 24 minke whales, 11 porpoises and eight pilot whales. For both males and females, the prevalence was 100% for all three host species, with a mean intensity of 1,727, 262 and 139, respectively. The mean body length of adult female A. simplex was 126 mm in minke whales, 71 mm in the porpoises and 73 mm in pilot whales; and for males the averages were, respectively, 106 mm, 57 mm and 68 mm. Eggs from the uteri of 32 females of length 87-176 mm collected in minke whale stomachs were counted in a Fuchs-Rosenthal chamber. Total egg production was measured in 14 females cultivated at sea. The female growth period was estimated to be 30-60 days, and apparently all eggs were shed during the last week of life. A female of size 150 mm produces approximately 1.5 million eggs. In the cultivation experiment, about 85% of the total egg production was shed during the first 3 days after spawning started.

Animals↗
PubMed2004

Herbivore effects on developmental instability and fecundity of holm oaks.

Plants are able to compensate for loss of tissue due to herbivores at a variety of spatial and temporal scales, masking detrimental effects of herbivory on plant fitness at these scales. The stressing effect of herbivory could also produce instability in the development of plant modules, and measures of such instability may reflect the fitness consequences of herbivory if instability is related to components of plant fitness. We analyse the relationships between herbivory, developmental instability and production of female flowers and fruits of holm oak Quercus ilex trees by means of herbivore removal experiments. Removal of leaf herbivores reduced herbivory rates at the tree level, but had no effect on mean production of female flowers or mature fruits, whereas herbivory tended to enhance flower production and had no effect on fruit abortion at the shoot level. Differences in herbivory levels between shoots of the same branch did not affect the size and fluctuating asymmetry of intact leaves. These results indicate compensation for herbivory at the tree level and over-compensation at the shoot level in terms of allocation of resources to female flower production. Removal of insect herbivores produced an increase in the mean developmental instability of leaves at the tree level in the year following the insecticide treatment, and there was a direct relationship between herbivory rates in the current year and leaf fluctuating asymmetry the following year irrespective of herbivore removal treatment. Finally, the production of pistillate flowers and fruits by trees was inversely related to the mean fluctuating asymmetry of leaves growing the same year. Leaf fluctuating asymmetry was thus an estimator of the stressing effects of herbivory on adult trees, an effect that was delayed to the following year. As leaf fluctuating asymmetry was also related to tree fecundity, asymmetry levels provided a sensitive measure of plant performance under conditions of compensatory responses to herbivory.

Animals↗
PubMed1996

The effect of immune sera from hamsters immunized with sandfly gut and whole body extract antigens on the fecundity and mortality of Phlebotomus duboscqi (Diptera: Psychodidae).

Phlebotomus duboscqi were fed on hamsters previously immunized with different concentrations of homogenized crude sandfly gut antigen and supernatant obtained from whole body extract. The humoral response in the rodents was quantified at different times post-immunization by the enzyme-linked immunosorbent assay. Sandflies were fed on either immunized or saline control hamsters and the effect of the blood meals on sandfly feeding, survival and fecundity was investigated. The humoral response in immunized hamsters as measured by the presence of P. duboscqi-specific IgG antibodies was significantly greater (P < 0.05) as compared to the controls. This difference was noted in sera collected on 15 and 25 days post-immunization. Sandflies fed on immunized hamsters had a significantly higher mortality (P < 0.05) and decreased egg production (P < 0.05) than those fed on unimmunized control hamsters.

Animals↗
PubMed1991

Development, survival, fecundity and behaviour of Haemaphysalis (Kaiseriana) longicornis (Ixodidae) at two locations in southeast Queensland.

The free-living stages of the tick Haemaphysalis (Kaiseriana) longicornis were studied at Mt Tamborine (526 m altitude) and Amberley (25 m altitude) in southeast Queensland between 1971 and 1980. Data are presented on the number of eggs and larvae produced, the moulting success of engorged larvae and nymphs and the survival and behaviour of unfed larvae, nymphs and adult females. Temperature, moisture, daylength, grass length and age of unfed ticks were investigated as sources of variation in development rates, fecundity or survival. At Mt Tamborine the life cycle was well synchronized with the seasons to produce one generation per year. At Amberley higher temperatures accelerated development rates and would have delayed diapause, so disrupting the life cycle.

Animals↗
PubMed1991

Subsequent testicular histology: fertility and fecundity of rats subjected to unilateral incarcerated inguinal hernia during the prepubertal period.

An experimental study was designed to evaluate subsequent ipsilateral and contralateral testicular histologies, fertility, and fecundity of rats subjected to unilateral incarcerated inguinal hernia during the prepubertal period. Three study groups each containing 12 rats (28-day-old) were established. In group 1 the rats were only anesthetized. In group 2 the rats had undergone a sham operation. Left-sided incarcerated inguinal hernias were created in rats constituting group 3. After the rats had reached 4 months of age, each male rat was housed with two known fertile female rats for 3 weeks. Male rats were then castrated and the testes were evaluated histologically. Female rats were followed for 30 additional days, and the number of females impregnanted and the number of rats given birth to by each female rat were recorded. Left-sided incarcerated inguinal hernia has caused a lessened testicular/body weight ratio in the left testes, and histological deteriorations in both left and right testes that were expressed through diminished mean seminiferous tubular diameter and mean testicular biopsy scores. The fertility rate was not affected, but the number of rats produced by each male rat was lesser after having the incarcerated inguinal hernia. Unilateral incarcerated inguinal hernia during prepubertal period resulted in deteriorated ipsilateral and contralateral testicular histology and diminished the exocrine function of testes in rats.

Animals↗
PubMed1991

Fecundity of anthelmintic resistant adult Haemonchus contortus after exposure to ivermectin or benzimidazoles in vivo.

A strain of Haemonchus contortus resistant to the benzimidazoles, ivermectin and salicylanilides was used to study the effect of exposure to ivermectin or oxfendazole on the number of eggs produced by adult female parasites. After anthelmintic administration there was a reduction in the faecal egg count of the infected lambs. Ivermectin caused a reduction in the number of eggs within adult parasites for up to 72 hours but this returned to higher than pre-treatment levels at 168 hours after treatment. After oxfendazole treatment there was an increase in the number of eggs stored in the adult parasites at 24 hours and then a significant reduction in the number of eggs for over 168 hours. This suggested that both ivermectin and oxfendazole have a deleterious effect on the reproductive potential of female H contortus although the parasites are resistant to these drugs. These results confirm the importance of allowing up to 10 days to elapse between the time of administration of an anthelmintic and the collecting of faecal samples when using the faecal egg count reduction test to identify anthelmintic resistance, especially when using benzimidazoles. The more prolonged effect on fecundity produced by oxfendazole may reflect the antimitotic action of the benzimidazole anthelmintics.

Animals↗
PubMed1984

The influence of fluctuating above-optimal temperature regimes on the fecundity of Biomphalaria pfeifferi (Mollusca: Planorbidae).

Biomphalaria pfeifferi of different sizes were subjected to fluctuating temperature regimes incorporating quantities of above-optimal heat ranging from approximately 2 to 75 degree hours greater than 27 degrees C per day. Fecundity over this range was found to be similar from 2 to 45 deg.h. greater than 27 degrees C/day but above this level egg production fell sharply. Histological examination of the gonads of experimental and control snails showed that not only was gametogenesis retarded above 45 deg.h. greater than 27 degrees C/day but also, and perhaps more importantly, development of the gonad was considerably impaired. It is hoped that this kind of information, which is based on field data, will be useful in assessing the likelihood of Schistosoma mansoni transmission becoming established in newly impounded waters in non-endemic areas.

Animals↗
PubMed1985

Density-dependent fecundity in Schistosoma mansoni infections in man.

An analysis is presented of autopsy data collected by Cheever in 1968 on the association between Schistosoma mansoni worm burdens and faecal egg counts. Significant negative relationships are found between the number of eggs/worm pair/g faeces and both the number of worm pairs and the total number of worms. A general, non-linear, statistical routine is shown to be the most practical method of fitting non-linear models to the observed density-dependent fecundity relationship. The conceptual and practical implications of density-dependence are discussed in the context of epidemiological field studies and chemotherapy programmes.

Animals↗
PubMed1976

Sexual function and fecundity after treatment for testicular tumors.

Questionnaires were mailed to patients who had undergone either radiotherapy, lymphadenectomy, or a combination of both as treatment for malignant disease of the testis in an attempt to define the effects of their therapy on sexual function, ejaculation, and fecundity. The forms returned by 29 patients with seminoma treated with irradiation alone indicated that little change had occurred in their sexual performance or sex drive. Diminished semen volume was reported by 10 patients but was severe in only 1. Two of 3 patients who desired children after therapy were successful. In patients with nonseminomatous testis tumor treated surgically, 42 of 50 reported a significant decrease in semen volume, but 7 of 12 who desired children following therapy were successful. The physiology of ejaculation is reviewed, and comments are offered on the means by which retroperitoneal lymphadenectomy may disrupt normal ejaculation.

Dysgerminoma↗
PubMed1990

Factors influencing lamb survival in a high fecundity Booroola Merino x South Australian Merino flock.

The effects of year of lambing, age of ewe and litter size on lamb survival and birthweight, and the effects of ewe mating weight and pregnancy wastage (ovulation rate minus litter size) on birthweight were examined in Booroola Merino x South Australian Merino ewes. Year of lambing, litter size and their interaction were significant (P<0.001) sources of variation for lamb survival. When birthweight was included as a linear and quadratic covariate for lamb survival, year of lambing and litter size and their interaction remained as statistically significant sources of variation. Year of lambing, litter size and pregnancy wastage contributed significantly (P<0.05) to variation in birthweight. Ewe liveweight at mating was not an important source of variation (P>0.05). Birthweight was significantly (P<0.05) reduced with an increase in pregnancy wastage. Improvement of birthweight of multiple birth lambs has some potential for increasing lamb survival. Other factors influencing lamb survival (year of lambing, litter size, pregnancy wastage) require further study so that strategies for reducing lamb loss in high fecundity Merino flocks can be developed.

Journal Article↗
PubMed1985

Plasma cortisol and sex steroid levels in Great Lakes coho salmon (Oncorhynchus kisutch Walbaum) in relation to fecundity and egg survival.

Plasma 11-ketotestosterone and cortisol levels in spawning male and female coho salmon (Oncorhynchus kisutch Walbaum) collected from a Lake Erie (Pennsylvania) stock were significantly lower (P less than 0.01) than in stocks of coho salmon at a comparable stage of sexual development collected from Lakes Ontario (two stocks) or Michigan. Plasma testosterone levels in female coho salmon from Lake Erie were significantly lower (P less than 0.01) than in females from Lake Ontario or Lake Michigan stocks. There were no significant differences in plasma testosterone levels in the males, or 17 beta-estradiol levels in male or female salmon of the four stocks sampled from the three study lakes. This apparent dysfunction in androgen and cortisol secretion in the Lake Erie stock is correlated with and may account for the low fecundity and poor expression of secondary sexual characteristics in that stock.

Animals↗
PubMedDate not supplied

Reproductive life of French-Canadians in the 17-18th centuries: a search for a trade-off between early fecundity and longevity.

One of the predictions derived from Williams' (1957) evolutionary theory of senescence is the existence of a trade-off between early fecundity and longevity. The population register of the French immigrants to Québec in the 17th century and of the first Canadians in the 17th and 18th centuries was used to detect such a trade-off in a noncontraceptive human population living at a time when longevity had not been prolonged by medical care and was not artificially shortened by wars, epidemics, or other external causes. No evidence for such a trade-off could be detected in these populations which had not yet reached the demographic transition phase (i.e., the historical period when longevity began to be extended and the progeny began to be reduced). Results are discussed in connection with the various studies aiming to test the Williams' theory.

Canada↗
PubMed2005

The effect of managed boar contact in the post-weaning period on the subsequent fertility and fecundity of sows.

This study demonstrates, in the artificial insemination of weaned sows, the advantage of isolating sows from contact with boars from weaning until the fourth day after weaning and then introducing a boar to elicit the estrous display before insemination. Weaned sows were isolated from boar stimulation during the immediate post-weaning period (Day 0 = weaning) until Day 4, when they were introduced to full boar contact. Sows were inseminated immediately upon display of oestrus shown by back pressure test (0 h) and 24 h later. Fertility data were collected after parturition. This "segregated service management" (SSM) resulted in significantly improved farrowing rate and litter size (P < 0.001) compared with the results in the group that had conventional continuous contact with the boar. All other measured performance indicators were similar between the groups. The benefit of SSM is believed to be due to artificial insemination being timed more closely to ovulation or to a more certain identification of true oestrus and/or improved sperm transport in the sow. SSM is recommended for enhancing the efficiency of boar-sow interaction to maximise fertility and fecundity at artificial insemination.

Animals↗
PubMed2004

Populations, longevity, mortality and fecundity of Chrysoperla carnea (Neuroptera, Chrysopidae) from olive-orchards with different agricultural management systems.

The influence that different styles of olive-orchard management (conventional, integrated, and organic) exert on the predator Chrysoperla carnea has been studied to strengthen this insect's role in the integrated management against pests. For this, the adult chrysopid populations were determined by McPhail traps, and laboratory examinations were made of certain biological characteristics of the first generation of adults captured in each of the olive orchards studied. The chrysopid populations increasing significantly during some months in the integrated and organic olive orchard. The most abundant species in all the zones was C. carnea, representing 95% of all captures in the conventional olive orchard. It was found that the larvae from the integrated olive orchard took longer to develop, while the pupae from the organic orchard evolved most rapidly to adulthood. The highest mortality rate was for larvae in the conventional olive orchard. The fecundity of the females from the organic orchards was significantly greater, presumably due to their greater longevity and shorter pre-oviposition period. These results can be used to improve conservation strategies and to increase C. carnea populations and their predatory activity.

Agriculture↗
PubMed2004

Negative lifestyle is associated with a significant reduction in fecundity.

OBJECTIVE: To evaluate the association patterns and quantify the effects of lifestyle on time to pregnancy (TTP). DESIGN: Observational study. SETTING: Teaching hospitals in Hull, United Kingdom. PATIENT(S): Two thousand and one hundred twelve consecutive pregnant women. INTERVENTION(S): A questionnaire inquiring about TTP, contraceptive use, pregnancy planning, previous subfertility/pregnancies, age, and lifestyle characteristics of either partner. MAIN OUTCOME MEASURE(S): We compared TTP, conception rates, and relative risk of subfecundity between subgroups with different lifestyle characteristics. RESULT(S): We found that TTP was significantly longer if the woman or partner smoked >15 cigarettes/day (P<.001 and.04, respectively), the partner consumed >20 alcohol units/week (P<.001), the woman's body mass index was >25 kg/m(2) (P<.001), their coffee and/or tea intake was >6 cups/day (P=.04), or if they were socially deprived (P<.001). Each of these effects remained unchanged after adjusting for the potential confounders. The relative-risks of subfecundity with each of these variables ranged between 1.4 to 1.9 (1.4 to 3.6 after adjustment). The effects of coital frequency and recreational drug use were insignificant. Couples who had >4 negative lifestyle variables had a sevenfold longer TTP; their conception probabilities fell by 60%, and they were 7.3-fold more likely to be subfecund than those without negative variables. CONCLUSION(S): Lifestyle has a significant and cumulative impact on fecundity. Dose-dependent effects occur with smoking, alcohol, and tea/coffee consumption. Appropriate counseling could result in substantial reductions in the referrals for fertility investigations and treatments.

Attitude to Health↗
PubMed2002

Cycle-specific and cumulative fecundity in patients with endometriosis who are undergoing controlled ovarian hyperstimulation-intrauterine insemination or in vitro fertilization-embryo transfer.

OBJECTIVE: To compare controlled ovarian hyperstimulation-intrauterine insemination (COH-IUI) or IVF-ET pregnancy rates per cycle (PR) and cycle and cumulative fecundity (f and cf) with COH-IUI or IVF-ET in endometriosis. DESIGN: Retrospective analysis. SETTING: Endometriosis research institute. PATIENT(S): Women with endometriosis and infertility (n = 313) who underwent consecutive COH-IUI (202 patients, 648 cycles), IVF-ET (111 patients, 139 cycles), or IVF-ET after failed COH-IUI (56 patients, 68 cycles). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Crude PR and life table-estimated f and cf. RESULT(S): With COH-IUI, 69 patients conceived; 65 conceived with IVF-ET; and 30 conceived with IVF-ET after COH-IUI (PR 11%, 47%, and 44%). With COH-IUI, six-cycle cf was 41%, and f for cycles 1-6 was 15%, 12%, 8%, 7%, 7%, and 0. With IVF-ET, three-cycle cf was 73%, whereas f for cycles 1-3 was 47%, 27%, and 33%. First-cycle f with IVF-ET was significantly higher than cf of six COH-IUI cycles. When the data were stratified according to the stage of endometriosis and women's age, the benefit of IVF over COH was even more pronounced. Prior COH-IUI failure did not adversely affect IVF-ET outcome. CONCLUSION(S): In endometriosis, PR, f, and cf are significantly higher with IVF-ET than COH-IUI, especially in stage IV and in women >38 years of age. Considering adverse effects of prolonged ovarian stimulation on endometriosis, IVF-ET should be the first-line approach in the management of infertility in this disease. If COH-IUI is attempted, it should not exceed three to four cycles.

Adult↗
PubMed1993

The effects of baseline ovarian cysts on cycle fecundity in controlled ovarian hyperstimulation.

Patients undergoing COH were prospectively studied in 174 cycles for the presence of baseline ovarian cysts. In 37.4% of all cycles, a baseline cyst > 10 mm mean diameter was found, but a cyst was more common in subsequent cycles than on the first (41.5% versus 15.8%). Cycle fecundity as determined by life table analysis was significantly higher if no baseline cyst were present (0.25 versus 0.06, P > 0.01). These findings suggest that baseline ovarian cysts may adversely affect the chances for pregnancy in COH not associated with IVF or GIFT.

Estradiol↗