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At least 37 records · Page 2Linked to original sources
PubMed1989

Exposure of Japanese quail embryos to o,p'-DDT has long-term effects on reproductive behaviors, hematology, and feather morphology.

Japanese quail eggs were injected with 1-(2-chlorophenyl)-1-(4-chlorophenyl)-2,2,2-trichloroethane o,p'-DDT(1-10 mg),1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane p,p'-DDT (1-10 mg), or, in one study, 0.5 mg chlordecone dissolved in 50 microliters of corn oil on day 1 of incubation. Hatchability was not decreased by o,p'-DDT or p,p'-DDT, as compared to corn-oil-injected controls, but was reduced in progeny of parents injected in ovo with either isomer. Tremor was observed for up to 4 days posthatching only in birds injected with 1.75-10 mg p,p'-DDT or chlordecone. Survivability to 5 weeks posthatch was reduced (less than or equal to 50%) in birds injected in ovo with 6.25-7.5 mg, o,p'-DDT or 1.75-5 mg p,p'-DDT as compared to corn oil (96%). Reproductive behaviors were attenuated in birds injected during development with o,p'-DDT, both DDT isomers decreased the total number of ovipositions, and o,p'-DDT increased the total number of eggshell malformations. Neither body weights nor reproductive organ weights at 12 weeks were affected by injection of either isomer. Exposure to DDT did not affect acquisition of a matched-to-sample food-reinforced response or subsequent responding on a random interval schedule of reinforcement. In another experiment, total circulating erythrocyte numbers were reduced in females after injection in ovo with o,p'-DDT but not after injection with p,p'-DDT. A primary humoral immune response was not affected by in ovo exposure to either isomer of DDT. In ovo exposure to o,p'-DDT but not to p,p'-DDT had long-term and estrogen-like effects on behavior and hematology in Japanese quail. Posthatch primary feather morphology was also altered by embryonic exposure to o,p'-DDT, p,p'-DDT, and chlordecone.

Animals↗
PubMed1975

The reproductive behavior of Aequidens paraguayensis (Pisces, Cichlidae).

The reproductive behaviour of aquarium-held Aequidens paraguayensis is described, with emphasis on a quantitative comparison of female-male parental roles. It is a biparental species. Eggs, laid on leaf litter, are guarded and aerated for about 32 hours (25--27 degrees C) and newly-hatched young are orally brooded for several days. Both sexes performed all parental activities; female-female did more fanning and mouthing of eggs, male-male more oral churning of young initially. The combination of substrate and oral brooding of young by both parents is rare among New World cichlids and is of interest for the study of the evolution of parental behaviour in fishes.

Aggression↗
PubMed1991

Testosterone stimulates reproductive behavior during autumn in mockingbirds (Mimus polyglottos).

Mockingbirds normally secrete little or no testosterone during the period of autumnal territoriality. To determine the behavioral effects of exogenously administered testosterone, 20-mm lengths of Silastic tubing filled with crystalline testosterone were implanted into free-living resident mockingbirds during the autumn. Control residents were given sealed empty implants. Focal animal sampling showed that T-implanted males sang significantly more than controls. Perhaps as a consequence, a significantly greater percentage of the T-implanted males acquired mates. Though nest building does not naturally occur in autumn, T-implanted males also showed significantly more nest building than control males. However, T-implanted males only built if there was a female in the territory, suggesting a synergy between the presence of testosterone and social cues provided by the female. Examination of the effects of testosterone on territorial aggression showed that despite the high levels of territorial activity common in this species in autumn, territorial fights were unaffected by the presence of testosterone. One aggressive call, known to function in fall territorial defense, was significantly decreased in T-implanted versus control males. The presence of fall testosterone appears to stimulate a number of reproductive activities in mockingbirds, leaving autumnal aggressive interactions either unchanged or decreased. We discuss the application of these data to the effects of testosterone on the mockingbird's reproductive behavior during the breeding season.

Animals↗
PubMed1992

[The genetic-demographic approach in anthropological research. XI. The structure of the reproductive behavior of Khakass families].

A detailed analysis of chronological intervals typical of reproduction process has been carried out in rural Khakassian populations to reveal the mechanisms of natural selection and gene drift. It is shown that the process of reproduction is connected with cultural traditions and economical activity of a population under study. The main characteristics of reproductive family behavior (the whole number of children and sex ratio, birth interval ect.) play a very important role in family and kin relationships, age, sex and marriage-migration structure of the population.

Anthropology, Physical↗
PubMed1992

Effect of yohimbine on the reproductive behavior of the male Nile crocodile Crocodylus niloticus.

The effect of yohimbine, an alpha 2-adrenergic blocker, on the reproductive activity of 12-year-old male, captive Nile crocodiles was tested on 18 animals equally divided into 3 ponds. In each pond, there were 6 males and 30 females. In the first group, six of six males received yohimbine capsules of 30 mg, twice a day, for 1 week. In the second group, two males of a group of six were administered a similar dose of yohimbine. Another group of six males in a separate pond were used as a control group. The yohimbine treatment had a significant (p less than 0.05) effect on the frequency of headslap display (the main behavioral pattern of reproductive activity) in all treated animals but did not result in a significant increase in copulation frequency. In the two treated groups, the reproductive period was prolonged by 3 weeks, 8-11 weeks. We found a significant increase in the fertility percentage of eggs laid by females in the male-treated groups (30.5% in control group females, 34.1% in the partly treated, and 39.0% in the pond where all six males were treated), even though no increase in mating frequencies was noted. This might be due to more successful copulations. During the treatment period, the daily activity peak, when the male's headslap performance was the most frequent, was shifted from 5:00-6:00 p.m. in the control to 4:00-5:00 p.m. in the treated group. This effect caused females to enter the water earlier than in the control group.

Alligators and Crocodiles↗
PubMed1979

Underlying family-size preferences and reproductive behavior.

Although about half the married women in a US survey said they wanted one or two children, underlying family-size preferences indicate a potential for many to have larger families. Using a measure of family-size preference that probes beyond single-valued statements, it is found that identical stated family-size desires or intentions may have different meanings for different people. Differences are systematically related to the stage in family building at which contraception begins, to current (or likelihood of future) use of effective methods, to the probability of continued childbearing, and to unwanted pregnancies.

Adolescent↗
PubMed1990

[Hormones, reproductive behavior and fertility in male silver foxes].

The relationships between gonadal and glucocorticoid hormones and reproductive behaviour were estimated in two groups of silver fox males classified as either low or high sex activity. Levels of testosterone and cortisol in peripheral plasma measured by radioimmunoassay did not differ between the groups. However, when receptive females were introduced to experimental males, levels of testosterone in plasma increased significantly only in the males with high sex activity within 1 hr after a test of sexual behaviour. Low sex activity of silver fox males correlated with an increased level of aggressive behaviour and decreased fertility.

Agonistic Behavior↗
PubMed1977

Facilitative and inhibitory influences of reproductive behavior on sperm transport in rats.

Six experiments were performed to investigate the effects of the rat's copulatory behavior on sperm transport in the female's reproductive tract. Data showed that (a) transcervical sperm transport in rats requires 6--10 min after ejaculation for completion; (b) transcervical transport of large numbers of sperm requires that the vaginal plug remain lodged tightly in the vaginal-cervical junction; (c) maintenance of an immobile posture by the male, and possibly by the female, at ejaculation facilitates the deposition of a tightly lodged vaginal plug and the transport of large numbers of sperm through the cervix; (d) a single intromission occurring within 2 min after ejaculation disrupts sperm transport, but more copulatory stimulation is required to disrupt sperm transport when delivered between 4 and 10 min after ejaculation; and (e) the average postejaculatory interval is long enough to prevent a male from disrupting the transport of most of his own sperm from the preceding ejaculation.

Animals↗
PubMed1990

Modes of estrus induction as a factor in studies of the reproductive behavior of rodents.

The choice of a mode of estrus for use in studies related to reproductive processes often is made arbitrarily. Females may be in hormone-induced estrus (HIE), cycling estrus (CE), male-induced estrus (MIE), or postpartum estrus (PPE). Although mode of estrus affects various aspects of copulatory behavior in different species in different ways, males mating with PPE females generally require more intromissions to reach ejaculation than with females in HIE or CE; males mating with females in CE generally attain more ejaculations than with PPE females. The duration of receptivity generally is shorter in PPE than in CE. Females in CE and PPE have different stimulus thresholds for pregnancy initiation, with the direction of the difference varying with the species. Among the other phenomena affected by mode of estrus are sperm competition, mate choice, and the Bruce effect. Because mode of estrus can be an important determinant of results, selection of a mode of estrus for any experiment should not be simply a matter of convenience. Further study of effects of mode of estrus is warranted.

Animals↗
PubMedDate not supplied

The sexual and reproductive behavior of American women, 1982-1988.

Comparison of 1988 data from the National Survey of Family Growth with 1982 data reveals that the proportion of U.S. women who have had sexual intercourse rose slightly, from 86 percent to 89 percent. Among teenagers, the proportion sexually active rose from 47 percent to 53 percent; most of the change is attributable to increases occurring among white and nonpoor teenagers, thus narrowing racial and income differences. Among women aged 15-44 in 1988 who have ever had intercourse, 67 percent reported that they had had two or more sexual partners in their lifetime. The proportion was highest among women aged 20-34 (about 70 percent), but 58 percent of sexually active teenage women reported having had two or more sexual partners. About 67 percent of women of reproductive age in 1988 were exposed to the risk of unintended pregnancy, up from 63 percent in 1982. Among these women, 35 percent rely on contraceptive sterilization to prevent pregnancy and 55 percent use reversible methods, while 10 percent use no method. Poor women are much more likely than nonpoor women to be using no method of contraception (15 vs. eight percent); among poor teenagers, this proportion reaches 25 percent. The level of contraceptive use at first intercourse among teenage women improved substantially between 1982 and 1988, however, rising from 48 percent to 65 percent. During 1984-1988, almost four in 10 births and almost six in 10 pregnancies among American women were unintended; most of these were mistimed, but 12 percent of births were unwanted ever.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Assessing the reproductive behavior of on- and off-reservation American Indian females: characteristics of two groups in Montana.

Only limited fertility and general reproductive health data exist on American Indians. Using data from the 1987 Montana American Indian Health Risk Assessment, we found that the fertility of American Indians in Great Falls and on the Blackfeet Reservation was similar to blacks in the U.S. and relatively high when compared with fertility of whites in the United States. The influence of the direct determinants of fertility (nuptiality, contraceptive use, and lactation) was very different for the populations examined in this study. Great Falls American Indians and the U.S. black population were similar regarding age at first sexual intercourse (very young), breastfeeding (low prevalence and short duration), planning status of pregnancies (high unplanned), and contraceptive use (only moderate use). In contrast, Blackfeet women on the reservation and the U.S. white population married relatively late, had very high contraceptive use, used effective methods of contraception, and had moderately high levels of breastfeeding. However, Blackfeet fertility was much higher than that of whites. Three interrelated reasons are suggested as possible explanations. Blackfeet couples either wanted high fertility, were relatively poor users of family planning methods, or used less effective methods until they had exceeded their desired family size after which time they turned to sterilization. These finds raise numerous questions concerning the social and economic factors that may account for these group similarities and differences. Further studies with much larger data sets are needed to address these issues adequately.

Adolescent↗
PubMed1977

Castration and reproductive behavior in the paradise fish, Macropodus opercularis (L.) (Osteichthyes: Belontiidae).

The effects of castration on male spawning behavior, nestbuilding and fertility were measured in a five day spawning trial with an intact female. Spawning and fertility decreased one week following castration while nestbuilding was unaffected. Sham operated males showed normal spawning and fertility. Two weeks postoperatively, fertility and spawning were increased paralleling partial regeneration of the testes. The antigonadotropin methallibure blocked testes regeneration and recovery of spawning in castrated males but it had no effect on reproductive functions of intact males. Spawning did not decrease in one-week castrated males which were administered testosterone enathanate. The results suggest that gonadal androgen facilitates sexual behavior in Macropodus.

Animals↗
PubMed1992

Copulatory behavior, reproduction, and sperm competition in two strains of male rats.

Long-Evans males fathered 72% of the offspring when one Long-Evans and one F344 male mated repeatedly with the same female throughout her estrus. When each male was restricted to one ejaculation and the second male was allowed to begin mating immediately following the first male's ejaculation, the second male left more offspring in each strain. However, the proportion was significantly greater for Long-Evans males. In contrast, there were no strain differences in either number of pregnancies or litter size in noncompetitive matings limited to two ejaculations, the minimal number required to induce pregnancy. The only consistent behavioral differences were the greater number of intromissions performed with shorter latencies by F344 males, differences that cannot readily be used to explain their reduced success. It was hypothesized that the two strains may differ in the adequacy of penile reflexes used to form, set, or dislodge sperm plugs.

Animals↗
PubMed1990

Ipsilateral and contralateral effects on cutaneous reflexes in a back muscle of the female rat: modulation by steroids relevant for reproductive behavior.

1. Multiunit EMG recordings of cutaneous reflexes--evoked in the back extensor, lateral longissimus (LL), by bilateral stimulation of nerves to dorsal flank skin--were studied in ovariectomized female rats with and without estrogen pretreatment. 2. Poststimulus time (PST) histograms of data from rats with and without estrogen pretreatment show that the axial EMG response (10-30 ms) to ipsilateral (ipsi) flank skin nerve stimulation is significantly shorter in latency (1.4 ms) and 67% larger than the response to contralateral (contra) flank skin nerve stimulation recorded at the same site (n = 29 pairs). 3. When late EMG responses were also evoked at 50-120 ms in 37% of ipsi and 29% of contra cutaneous reflexes, the incidence of multiunit activity in the late peak was significantly greater in rats pretreated with silastics containing 100% estradiol (E) compared with 10% E or cholesterol controls. 4. When an ipsi cutaneous reflex in LL was conditioned by a stimulus to the contra flank skin nerve at a condition-test interval of 30 ms (C-T 30 ms), the average number of discharges in the early peak of the histogram was double that in the histogram obtained from the unconditioned ipsi reflex, independent of estrogen pretreatment. 5. In 12 out of 19 cases in which a contra cutaneous reflex was conditioned by a stimulus to the ipsi flank skin nerve (C-T 30 ms), the number of discharges in the early peak of the histogram was less than that in the early peak of the histogram derived from the unconditioned contra response, independent of estrogen pretreatment. 6. Intravenous injections of progesterone (P) or its metabolite 5 alpha-pregnane-3 alpha-ol-20-one (tetrahydraprogesterone, THP) decreased the magnitude of the early peak of the ipsi cutaneous reflex and the contra cutaneous reflex in LL, independent of estrogen pretreatment. At the same time, it did not reduce the magnitude of the early peak evoked by either ipsi or contra nerves after conditioning from the other side at C-T 30 ms. 7. As a consequence, the percentage facilitation of ipsi cutaneous reflexes by contra cutaneous conditioning was significantly increased after P or THP. This suggests that these steroids can selectively enhance behaviors involving bilateral inputs. 8. An unchanged axial motoneuron pool output to bilateral cutaneous inputs after P and THP, in spite of reduced motoneuron responses to cutaneous inputs from each side of the body, implies an increased gain in the reflex circuit.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1977

Portions of the central nervous system controlling reproductive behavior in Drosophila melanogaster.

Drosophila melanogaster sex mosaics were tested in their courtship interactions with females and then with males. The distribution of genetically male and female tissues in each mosaic was determined with respect to an external cuticle marker and an internal enzyme marker. Performance of malelike courtship was correlated with the genotype of various tissues, with special attention being paid to the genotypes of head and thoracic ganglia. Male tissue in the left or right dorsal brain is necessary and nearly always sufficient to trigger early courtship actions--following of females and wing extension at them--but male tissue in both the dorsal brain and thoracic ganglia is necessary for attempted copulation to occur. Female tissue on or in the abdomen is nearly always necessary and sufficient for a mosaic to be courted by a male.

Animals↗