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PubMed1991

Embryonic development and incidence of aneuploidy in two rabbit strains of different fecundity.

The correlation between strain fecundity and (i) development and (ii) rate of aneuploidy was studied in rabbit preimplantation embryos obtained from 2 strains of different fecundity. Embryos were investigated at Days 3-6 (preimplantation development) or Days 2, 4 and 6 post coitum (aneuploidy). Embryonic size and cell proliferation varied on the days of investigation, but with no consistent tendency in favour of one strain. The incidence of aneuploidy did not differ significantly between embryos from the 2 strains (P greater than 0.05). The multifactorially determined criterion of prolificacy was not selectively correlated with overall differences in embryonic preimplantation growth and rate of aneuploidy.

Aneuploidy↗
PubMedDate not supplied

Behavior of triatomines (Hemiptera:Reduviidae) vectors of Chagas' disease. IV. Fecundity, fertility and longevity of Panstrongylus megistus (Burm., 1835) pairs and virgin females starved under laboratory conditions.

A laboratory study was conducted on the fecundity, fertility and life span of Panstrongylus megistus pairs and on the fecundity and life span of P. megistus virgin females submitted to starvation after the last moulting. Of the mated females, 22.2% laid eggs, 4.4% of which were fertile. Females resisted starvation more than males. Of the starved virgin females, only 10% laid eggs, with a low egg-laying rate (0.47) per female. Resistance to starvation was lower in virgin than in mated females.

Animals↗
PubMedDate not supplied

Fecundity, parity, and adult feeding relationships among Nyssorhynchus malaria vectors from Venezuela.

Relative to their pre-engorgement weights, nulliparous Anopheles nuneztovari consumed significantly smaller blood meals than A. marajoara, A. triannulatus or A. aquasalis. When females were deprived of sugar before blood feeding, only one-quarter of A. nuneztovari, but more than two-thirds of A. marajoara, A. triannulatus and A. aquasalis matured eggs. Sugar feeding before blood, or two successive blood meals by sugar-deprived females, increased the proportion of nulliparous A. nuneztovari which developed eggs, but not significantly so. Nearly all individuals of nulliparous, sugar-fed A. marajoara, A. triannulatus and A. aquasalis matured eggs after one blood feeding. Among A. nuneztovari, A. marajoara and A. aquasalis that matured some eggs in the laboratory, there were no positive correlations between the number of eggs developed and relative blood meal size. However, blood meals larger than the mean size significantly increased the chance that A. nuneztovari would develop some eggs. Mean fecundities of gravid A. nuneztovari and A. marajoara reared in the laboratory were significantly lower than those of the same species captured at human bait in nature. Post-engorgement access to sugar by A. nuneztovari (captured at human bait) did not influence fecundity, but significantly enhanced survivorship and the proportion of individuals which retained eggs. Release-recapture experiments revealed that relatively small blood meals are typical of A. nuneztovari only during the first gonotrophic cycle. We suggest that multiple blood feeding, seemingly necessary for most A. nuneztovari to develop a first clutch of eggs, may increase the probability of infection with Plasmodium vivax where this mosquito species is a primary vector.

Animals↗
PubMed2001

Selection, egg viability, and fecundity of the sugarcane borer (Lepidoptera: Crambidae) with tebufenozide.

Two separate attempts to select the sugarcane borer, Diatraea saccharalis (F.), for resistance to tebufenozide were unsuccessful. Both selected colonies were lost after the fourth generation due to a lack of oviposition. Differences were not detected in fecundity or percent egg viability for 5-d-old third instars exposed to concentrations (EC5, EC15, and EC30) of tebufenozide for 7 d. Decreases (P < or = 0.01) in mean female pupal weights were detected in larvae exposed to EC15 and EC30 concentrations. An ovicidal impact using serial dilutions of tebufenozide (10, 100, and 200 ppm) also was detected. Percent viability was reduced from 98% for untreated eggs to 61% for eggs dipped in 10 ppm and below 6% for eggs dipped in > or = 100 ppm. Eggs treated with 200 ppm did not hatch. Though some embryonic development was observed on eggs treated with the high concentrations (100 and 200 ppm), sclerotization of head capsule was not apparent. The ovicidal property of tebufenozide may enhance its effectiveness in controlling populations of the D. saccharalis on an area-wide basis. Fecundity and egg viability were affected in later generations of selection; however, separate studies assessing individuals that were exposed to sublethal concentration (EC5, EC15, and EC30) of tebufenozide as third instars for 7 d in one generation did not detect differences.

Animals↗
PubMed2002

Fecundity in twospotted spider mite (Acari: Tetranychidae) is increased by direct and systemic exposure to imidacloprid.

The effect of imidacloprid on fecundity in twospotted spider mites, Tetranychus urticae Koch, was investigated in laboratory experiments using individual females on bean leaf discs. Mites were directly exposed to spray formulations of imidacloprid or fed on discs cut from a systemically treated bean plant. Imidacloprid-treated T. urticae produced 10-26% more eggs during the first 12 d of adult life and 19-23% more during adulthood compared with a water-only treatment. Increased egg production occurred immediately after exposure and lasted for about 15 d in sprayed mites. In mites exposed to imidacloprid by ingestion, increased egg production was not apparent until after 6 d and lasted until about day 18. Longevity was significantly greater in mites that ingested imidacloprid but not in sprayed mites. The significance and importance of imidacloprid-stimulation of fecundity in T. urticae to pest management in crop systems like hops, which routinely use this insecticide, is discussed.

Animals↗
PubMed2005

Selective insecticide-induced stimulation on fecundity and biochemical changes in Tryporyza incertulas (Lepidoptera: Pyralidae).

The use of selective insecticides in rice, Oryza sativa L., fields often causes resurgence of nontarget pest insects. This study was conducted to investigate the effect of two selective insecticides, buprofezin and imidacloprid, on Tryporyza incertulas (Walker), a nontarget pest. After larval feeding on rice plants treated with each insecticide, fecundity, ovary protein content, and titer of juvenile hormone III (JHIII) in the resulting female moths were determined with 'Xiushui 63' rice susceptible to T. incertulas and 'Zhendao 2' moderately resistant to T. incertulas. The fecundity of females developed from larvae that fed on the insecticide-treated Xiushui 63 plants was stimulated compared with that of moths from larvae that fed on rice plants that were not treated with either insecticide. There was no stimulating effect in females from larvae that fed on insecticide-treated Zhendao 2 plants. The weight of fourth instars (final instars) that fed on the insecticide-treated Xiushui 63 rice plants was significantly greater than that of control, increasing by 50.3 and 46.7% for 60 and 112.5 g (AI) ha(-1) buprofezin, and by 23.7 and 19.5% for 15 and 37.5 g (AI) ha(-1) imidacloprid treatments, respectively. Ovary protein content in adult females developed from larvae that fed on the rice treated with the high dose of buprofezin was significantly higher than that in control. For the high and low doses of imidacloprid during the second instar, and the low dose of imidacloprid during the fourth instar, JHIII titers in female adults were also significantly higher than that in control, increasing by 152.81, 90.52, and 114.19%, respectively.

Animals↗
PubMed2002

Induced immunity against the mosquito Anopheles stephensi (Diptera: Culicidae): effects of cell fraction antigens on survival, fecundity, and plasmodium berghei (Eucoccidiida: Plasmodiidae) transmission.

Two subeellular fractions from the midgut of the malaria mosquito Anopheles stephensi (Liston) were used to immunize BALB/c mice. Mice were subsequently infected with the rodent malaria parasite Plasmodium berghei (Vineke & Lips), and the effects of anti-mosquito immunity on mosquito survival and fecundity and on parasite transmission were investigated. Mosquitoes were infected directly from mice (in vivo) or by feeding cultured ookinetes through a membrane (in vitro). Infections were monitored by counting oocysts on the midgut wall. Microvilli extracts induced a strong and partially specific antibody reaction against the midgut, which was manifest as decreased survival in in vivo fed mosquitoes and reduced fecundity in both kinds of feeding. Antisera against microvilli reduced the mean intensity of P. berghei oocysts when fed in vitro, while mosquitoes fed antiserum against basolateral plasma membranes in vivo, showed higher oocyst burdens.

Animals↗
PubMed2002

Negative influence of Gammarinema gammari (Nematoda) on the fecundity of Microphallus papillorobustus (Trematoda): field and experimental evidence.

The gammarid amphipod Gammarus insensibilis frequently harbors adult individuals of the ectoparasitic nematode Gammarinema gammari as well as metacercariae of the trematode Microphallus papillorobostus. After the demonstration in a previous study of a negative relationship between the abundance of these 2 parasites, the nature of the relationship between these 2 parasites was explored in more detail by studying, in the field and in the laboratory, the influence of nematode abundance on trematode fecundity. In gammarids collected in the field, a negative relationship between metacercarial fecundity and the number of co-occurring nematodes was found. By manipulating the nematode abundance in the laboratory, it was confirmed that G. gammari has a negative effect on egg production in M. papillorobustus.

Animals↗
PubMed2004

The effect of parasitism on host fecundity is dependent on temperature in a cockroach-acanthocephalan system.

The fitness of infected organisms can vary greatly depending on the temperature at which they find themselves. Understanding the role of temperature in the fitness of infected organisms can be crucial to population studies, epidemiological studies, and when screening for biological control agents. We measured the effect of parasitism on host survival and reproduction at 4 constant temperatures using the acanthocephalan parasite Moniliformis moniliformis and its intermediate host, the cockroach Supella longipalpa. Infection did not affect cockroach survival at any temperature. Infection had a negative impact on cockroach fecundity but only at higher temperatures (28 and 31 C) and only later in infection (>20 days postinfection). At lower temperatures, infected and uninfected cockroaches had similar fecundities throughout the duration of the experiment (120 days). This study, along with previous studies, suggests that researchers would do well to consider environmental variables when exploring the effects of parasitism.

Analysis of Variance↗
PubMed2003

The effect of lead-contaminated soil from Canadian prairie skeet ranges on the neutral red retention assay and fecundity in the earthworm Eisenia fetida.

The sublethal effects of lead (Pb) on the earthworm Eisenia fetida were evaluated in the laboratory using freshly spiked soil and soil collected from Canadian prairie skeet ranges. After a four-week exposure to soil spiked with lead acetate, earthworm neutral red retention time (NRRT). soil Pb concentrations, and earthworm Pb body burdens were measured. Lysosomal NRRT was reduced in a concentration-dependent manner (p < 0.0001), and NRRT was negatively correlated with earthworm Pb body burdens (r = -0.80, p < 0.0001). To evaluate the effects of aged Pb, earthworms were exposed to soil from three skeet ranges, and responses were compared with three matched reference sites. After a four-week exposure, NRRT, growth, fecundity, soil total Pb levels, and earthworm Pb body burdens were measured. The potentially bioavailable fraction of Pb in these sites was measured using a Ca(NO3)2 extraction. Growth and fecundity did not differ significantly between any of the skeet ranges and their reference sites. However, NRRT was significantly reduced in all three ranges compared with their respective reference sites (p < 0.05), indicating that the neutral red retention assay (NRRA) may be useful for detecting toxicity and potential hazards at Pb-contaminated sites. Lysosomal NRRT was negatively correlated with soil Ca(NO3)2-extractable Pb (r = -0.80, p < 0.0001) and soil total Pb (r = -0.73, p = 0.001). Lysosomal NRRT was negatively correlated (r = -0.67, p < 0.002) with earthworm Pb tissue levels.

Animals↗
PubMedDate not supplied

Laboratory investigations of trichomycete prevalence, abundance and fecundity in a Smittium-simuliid model.

Smittium, the most speciose genus of the "gut fungi" (Zygomycota: Trichomycetes), is found attached to the hindgut cuticle of larval aquatic Diptera. Smittium spp. colonize several host families (e.g., Smittium culisetae in Chironomidae, Culicidae and Simuliidae), but some species appear to be specific to a single host family (e.g., Smittium morbosum Sweeney in Culicidae). The specificity of Smittium spp. within a host family has been difficult to resolve. This research presents evidence that certain Smittium spp. differentially colonize particular species of black fly (Diptera: Simuliidae) hosts as measured by differences in prevalence, abundance and fecundity. Reasons for this differential occurrence and fecundity in hosts are unclear but might include fungal responses to variations in host morphology, physiology, distribution or behavior. Variable fitness of Smittium spp., within a suite of available hosts, could be a factor in the diversity of this fungal group.

Animals↗
PubMedDate not supplied

Laboratory evaluation of pyriproxifen treated bednets on mosquito fertility and fecundity. A preliminary study.

AIM: The study evaluated the effect of pyriproxifen treated bednets on mosquito fertility and fecundity in the laboratory. Pyriproxyfen (insect growth regulator) has been considered as a possible tool for management of pyrethroid resistance in mosquitoes. There are documentations of the effectiveness of pyriproxifen in controlling larval development when applied directly to breeding site. Considerations have been given to the use of pyriproxyfen on bed nets for sterilizing effect on mosquitoes resistant to pyrethroids. METHOD: Groups of mosquitoes (Anopheles stephensi Beech) were exposed to bednet treated with 2% Pyriproxyfen and untreated netting 24 hrs after blood feeding. After oviposition, egg counts were done for each mosquito in the two groups. Larvae emerging from the laid eggs by each mosquito were counted. Three sets of experiments were successful. RESULTS: There was no significant difference in number of eggs laid between the two treatment groups (p=0.177). There was statistically significant difference in the number of laid eggs that hatched between the treatment types (p=0.0061). There was also statistically significant difference in the mean number of eggs that hatched between the experiments (p=0.0013). The mean number of eggs retained in the pyriproxyfen group was higher (70.3) than in the control group (41.6). This difference was not statistically significant with the small sample tested (p=0.08). CONCLUSION: The results suggest that 2% pyriproxyfen on bed nets has no effect on An. stephensi fecundity. Reduced fertility of eggs laid by mosquitoes exposed to pyriproxyfen treated bed nets was observed.

Animals↗
PubMed1999

Increased fecundity of Aedes aegypti fed human blood before release in a mark-recapture study in Puerto Rico.

Laboratory experiments suggest that utilization of blood rather than natural sugar sources for energetic needs affords female Aedes aegypti a reproductive advantage over conspecifics that use sugar. To test this hypothesis under field conditions, we carried out a mark-release-recapture study in Florida, PR. Adult females (F1) reared from field-collected eggs were provided with a diet of human blood alone or human blood plus a 20% honey solution before their release. Backpack aspirators were used to collect mosquitoes from release houses for 5 consecutive days beginning the 2nd day after release. Survival was estimated from the slope of the regression line of the log-transformed daily number of recaptures for each treatment group. To compare fecundity of the treatment groups, each recaptured female was dissected, ovaries were removed, oocytes counted, and Christophers' stages of oocyte development scored. Recapture rates were 30% for the blood-only group and 23% for blood plus honey group. The daily survival rate of the blood-only group (55%) was not statistically different from that of the blood plus honey group (69%) (t = 0.32, P > 0.05). By analysis of variance, fecundity (average number of stage III-V oocytes) was significantly higher in the females fed human blood alone (n = 103, 109 oocytes/female) than in the group fed on blood and honey (n = 50, 95 oocytes/female) (P = 0.0007). The observed gonotrophic cycle length of the recaptured females ranged from 3 to 7 days. Results from our field study are consistent with laboratory life-table experiments that suggest feeding exclusively on human blood provides a reproductive advantage for female A. aegypti.

Aedes↗
PubMed2000

The effects of Nosema algerae Vavra and undeen (Microsporida: Nosematidae) pathogen of Culex pipiens L.(Diptera: Culicidae) from Egypt on fecundity and longevity of the host.

A microsporidian, Nosema algerae Vavra and undeen, was found parasitizing larvae and adults of a laboratory colony of Culex pipiens L. originated from Gharbia Governorate. A detailed examination of the developmental stages of the pathogen under light and electron microscopes showed that they are typical of the original characteristics of N. algerae. Other observations on the infected individuals revealed that spores of the pathogen were found in all organs of the infected mosquitoes except the nervous system. The most heavily infected organ was the alimentary canal, particularly the mid gut. The susceptibility of the different larval instars of a laboratory maintained Cx. pipiens colony to infection by N. algerae was determined. Using 24 hours exposure to a range of doses between 40 and 5 x 10(5) spores per cm, larvae of the 1st and 2nd instars were more susceptible to infection than 3rd and 4th instar larvae as indicated by the differences in the estimated IC50 dosages. The dosages of N. algerae which produced 50% mortality (LC50) in each group of treated larvae was approximately 25-30 times higher than the doses that caused 50% infection. When a sublethal dose of 1.2 x 10(3) spores per cm2 of N. algerae was used to induce infection in each of the different larval instars infection rates of 100% were obtained in all exposed larval instars and in adults developed from them. Females from larvae infected with N. algerae had significantly reduced fecundity, fertility, and longevity regardless the larval instar in which infection was initiated. However, the reduction was obviously high when 1st and 2nd instars were exposed. The accumulative effects of reduced survival and fecundity on the reproductive potential of the infected females derived from larvae that were infected as 1st and 2nd instars probably serve to limit the natural increase of mosquito populations. Further studies are necessary, however, to determine the efficacy of this pathogen on target species in the natural environment where the combined effect of the pathogen and environmental stresses may enhance its pathogenicity.

Animals↗
PubMedDate not supplied

Age, growth and fecundity of the silver mullet, Mugil curema (Pisces: Mugilidae), in coastal areas of northeastern Venezuela.

We studied fecundity and growth in populations of the silver mullet, Mugilcurema, in coastal areas of northeastern Venezuela between March 1992 and July 1993. The average number of oocytes in gonads of 23-42 cm adults was 54 x 10(4), and the relative fecundity was 1,311 oocytes g-1 of fish. The size of mature oocytes did not vary in different portions of the same gonad (p > 0.05) or among the adults in three populations studied. The average egg diameter for adults was 426 microns (CI = 4.34). Age of juveniles, collected from the La Restinga Lagoon at about monthly intervals, from counts of growth lines on the otoliths ranged from 50 to 240 days. The relation of age (number of growth lines) to standard length follows an exponential growth curve. The growth of juveniles varied seasonally and was greatest during the rainy season (April to August), when temperatures were highest. The time of spawning has probably been adapted so that peak recruitment into the lagoons occurs just prior to the rainy season when conditions for growth are most favorable.

Age Factors↗
PubMed1999

[Heterologous fecundation and the issue of paternity: a long lasting querelle].

The almost total disinterest of legislators in the area of artificial fecundation has prompted the frequent involvement of magistrates thereby giving rise to innovations which depart from the previous tendencies of jurisprudence. The latest sentence of the Supreme Court on heterologous fecundation and the issue of paternity merits special attention because of its innovative principles.

History, 20th Century↗
PubMed2000

Anti-fecundity immunity in mice immunized with anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum.

OBJECTIVE: To observe the effects of anti-fecundity and anti-embryonation immunity of anti-idiotypic monoclonal antibody NP30 of Schistosoma japonicum on female adult worm. METHODS: The active immunization of C57BL/6 mice was conducted by means of three intraperitoneal injections of NP30. The control group was injected with SP2/0 ascites intraperitoneally. RESULTS: On the twenty-seventh day after challenge infection, the number of eggs in the liver tissue and in uterus of the group immunized with NP30 decreased by 30.91% and by 38.55%, respectively. On the thirty-ninth day after the challenge infection, the number of mature eggs in the liver tissue of the group immunized with NP30 decreased by 66.63% and the number of dead eggs increased by 60.66%. CONCLUSIONS: NP30, with which mice were actively immunized, possesses double effects of anti-fecundity and anti-embryonation immunity on female adult worm of Schistosoma japonicum, therefore it can be used as a promising candidate of anti-pathologic vaccine molecule against Schistosomiasis japonica.

Animals↗
PubMed2001

[Effect of human blood feeding on the fecundity, fertility and biological cycle of Rhodnius prolixus (Hemiptera: Reduviidae)].

The effect of several human blood fractions artificially fed to Rhodnius prolixus Stal 1859 on oviposture (fecundity), egg-hatching (fertility) and life cycle was observed. Specimens fed on man's blood were more fecund than those fed with woman's blood. There were no significant differences in fertility related to host sex. The nymphal development time and number of feedings to molt to the following instar were estimated. Animals fed only on blood plasm did not finish nymphal development, while those fed only blood red cells ended their life cycle in the third nymphal instar. Total life cycle lasts 129 days in individuals fed with whole blood.

Animals↗