Female Copulation Research Articles

Remating inhibition in the melon fly,Bactrocera (=Dacus) cucurbitae (Diptera: Tephritidae): Copulation with spermless males inhibits female remating

Eight hour copulation of the melon fly,Bactrocera cucurbitae, which usually mates at dusk and finishes copulation at dawn, inhibited female remating, while 3 h copulation did not. Copulation of females with either normal or virgin sterile males inhibited female remating. Sperm-depleted sterile males inhibited female remating at the same rate as normal males when the copulation duration was 8 h, indicating that existence or amount of sperm in females' spermathecae is not important in remating inhibition. Females of a wild strain remated later than females of a mass-reared strain, irrespective of strains of 1st and 2nd males. This suggests that the females may control their own remating, or that there is a difference between wild and mass-reared strains in their sensitivity to a male substance that inhibits females' receptivity.

Ovarian and endocrine patterns associated with reproductive abnormalities in llamas and alpacas

Summary: Ovarian activity was characterized in llamas and alpacas with hypoplastic ovaries, cystic follicles, or ovulatory failure. Ovarian follicular activity was determined by transrectal ultrasonography and urinary estrone sulfate analysis; pituitary response was determined by measurement of plasma concentrations of luteinizing hormone. Llamas and alpacas with hypoplastic ovaries had follicles ≤ 6 mm (minimal ovulatory size, 7 mm). Cystic follicles, defined as >12 mm, were maintained for a mean of 9 days. Follicular activity in the ovary contralateral to the cystic follicle tended to be suppressed while the cystic follicle was present. Ovarian response to copulation in females with cystic follicles varied according to the stage of the cystic follicle. Animals with ovulatory failure did not release adequate luteinizing hormone after copulation, even though they had mature and normal follicles (8 to 12 mm). The cystic follicle syndrome appears to be temporary, whereas the syndromes involving hypoplastic ovaries and ovulatory failure may permanently affect fertility.

Female control of extra-pair fertilization in tree swallows

In a Canadian population of tree swallows, Tachycineta bicolor, DNA fingerprinting has previously shown that half of all broods contain many offspring resulting from extra-pair copulations (EPCs), whereas the other half contain only legitimate offspring. This bimodal pattern of extra-pair paternity might be due to variation in the effectiveness of male paternity guards, variation in female ability to resist EPCs, and/or variation in female pursuit of EPCs. Here we report experimental evidence for female control of copulations and fertilizations and the occurrence of two alternative copulation strategies among females in this population. Ten paired male tree swallows were removed on the day their mates laid the first egg. Replacement males took over the nestbox within 0.5–23 h and attempted to copulate with the widowed female. Assuming that eggs were fertilized approximately 24 h prior to laying, the first two eggs were fertilized before the male was removed, while the third and subsequent eggs could potentially be fertilized by the replacement male. Fingerprinting revealed that the first two eggs were sired by the resident males in five nests and by extra-pair males in the remaining five nests. The widows that had been faithful to their initially chosen mate rejected copulation attempts by the replacement male until most of the eggs had been laid. Consequently, nearly all eggs laid by these females were sired by the original male. The widows that had been unfaithful prior to male removal copulated sooner with the replacement male than females that were faithful to their mate. However, these replacement males also had a very low fertilization success; most eggs were sired by males that were not associated with the nest. This is consistent with the situation in non-experimental nests where unfaithful females copulate with their mate at the same rate as faithful females, yet unfaithful females have a majority of offspring sired by extra-pair males. We conclude that fertilization patterns to a large extent are determined by the female through active selection and rejection of copulation partners, though our results also allow some speculation that females have control over sperm competition. Female copulation tactics are probably determined some currently unknown fitness benefits of having the offspring sired by particular males.

Frequency of Female Copulations with Multiple Males and Sexual Selection

Female animals often copulate with more than a single male during one fertile period. I suggest that female propensity to engage in such multimale copulations is caused by constraints on female mate choice set by the availability of males. A simple graphic model of mate choice after formation of pair bonds suggests that the probability of female engagement in copulations with multiple males should be inversely proportional to the availability of preferred mates at the time of mate choice. This problem will be present whenever males and females establish pair bonds, and the male availability constraint on female mate choice will be more important for mating systems in which males attract only a single or few females. Monogamy thus particularly often sets the stage for sexual selection via multiple matings. Male availability to females during mate choice differs between mating systems, and the relative frequency of female copulations with multiple males should be inversely related to male availability. If f...

Reproductive Ecology of the Xanthid Crab Eriphia Smithii Mcleay

Tagging studies of the xanthid crab Eriphia smithii were carried out from May-October 1986, and May 1987–October 1988 on a rocky shore near the Marine Station of Tokyo University of Fisheries, at Banda, Chiba Prefecture, Japan. At a separate location at Banda between May 1987 and October 1988, specimens were collected for laboratory measurement of the gonad index (GI). Spawning occurred predominantly in June and August, with nonovigerous females showing elevated GI levels particularly in late May and mid-July. From evidence from tagging experiments, the number of spawnings that occur over an intermolt period is 1 or 2. Molting and copulation in females occurred from June-September. Three types of reproductive patterns are used by this species at Banda: (1) Females molt and copulate in July-August, and in the following year spawn in June-July, releasing zoeae during July-August, after which they molt and copulate again during July-August. (2) Females molt and copulate in August-October and in the following year spawn twice between June and August, releasing zoeae from July-October. After release of zoeae they again molt and copulate (August-October). (3) Females molt and copulate early in the summer, between June and July, and subsequently spawn soon afterwards during July-August, and then molt and copulate during July-September.

Sexual behavior and urinary ovarian hormone concentrations during the lowland Gorilla menstrual cycle

Sexual behaviors were recorded and urinary concentrations of total estrogens and pregnanediol-3-glucuronide (Pdg) measured during six normal menstrual cycles from two female lowland gorillas in a stable, captive group. Frequencies of female presentations, mounts, and copulations were positively associated with peak estrogen values but not with elevations of Pdg. These results support the observation that sexual behaviors in the gorilla occur most frequently in the periovulatory period and that copulations serve primarily a sexual function.

P-Chlorophenylalanine alters pacing of copulation in female rats

When tested in apparatus that allowed them to determine their contacts with conspecifics, including sexually active male rats, estrogen- and progesterone-treated female rats systematically treated with para-chlorophenylalanine (PCPA), a tryptophan hydroxylase inhibitor, showed reduced frequency of coital contacts and reduced duration of interactions with sexually active males. PCPA administration did not alter contacts with noncopulating males or other females nor did treated females differ from controls in ability to display lordosis or posing, both stereotyped behaviors characteristic of female rats in behavioral estrus. It is suggested that the alteration of temporal pacing of copulation in the PCPA-treated females is a result of drug-induced changes in the processing of exteroceptive stimuli.

Influence of male aggression on mating of gorillas in the laboratory.

The frequency of sexual interactions between oppositely-sexed pairs of gorillas tested in the laboratory was directly related to the frequency of male aggression directed toward the female. The data suggest that male aggression stimulated female presenting and copulation, and accounted for mating temporally dissociated from the periovulatory period. Among the great apes tested in the laboratory, the male primarily accounts for mating that is unlikely to contribute to reproduction.

Reproductive Behavior in the Rhesus Monkey: Social and Endocrine Variables

SYNOPSIS. Social groups of rhesus monkeys ( Macaca mulatto ) living in outdoor environments exhibit a distinct seasonal mating pattern and female rhesus are observed to be sexually receptive for discrete periods averaging about 9 days duration. In the laboratory environment mating occurs throughout the year and, in the pair test, female rhesus are observedto be sexually receptive through all phases of a menstrual cycle, with a periovulatory peak incopulatory behavior. The apparent conflict between results from field and laboratory studies has been difficult to resolve because of methodological limitations inherent in each study environment. Studies conducted on social groups of rhesus monkeys housed in outdoor compounds, an environment in which the species typical seasonal mating pattern is preserved and which allowsfor concomitant measurement of behavioral and hormonal variables, provided information about the covariance between female sexual behavior and ovarian cycles. Female copulations were observed only in association with ovulatory cycles, and were limited to the follicular and peri-ovulatory phases of such cycles, demonstrating that copulatory behavior in female rhesus monkeys is strongly influenced by cyclic hormonal variables. The studies also revealed that females tend to conceive on the first ovulatory cycle of the season, that there was no synchrony of cycles among the females, and that the best predictor of the timing of ovulation in a particular female is reproductive outcome in the previous year.

Periodic, short-term heat exposure and reproductive function in male and female rats.

Reproductive function of male and female rats was examined in relation to periodic, short-term heat treatment. Daily exposure to an environmental temperature of 38.2 degrees C for 55 min elevated rectal temperatures to 39.9 and 41.2 degrees C in male and female rats, respectively. Heat exposure tended to decrease copulation in males cohabitated with unheated females. The rate of conception was affected similarly, and fetal survival tended to be reduced by paternal heat treatment. Estrous cycles were disrupted initially in heat-exposed females, but the rate of copulation and conception of females cohabitated with unheated males was unaltered by heat treatment. However, maternal heat exposure impaired prenatal survival and growth. During lactation, a high incidence of maternal and pup deaths was observed at approximately 14 days postpartum. Maternal deaths were coincident with a decrease in thermoregulatory ability and rectal temperatures exceeding 42 degrees C.

Validation of the in vivo somatic mutation method in the mouse as a prescreen for germinal point mutations.

The in-vivo somatic mutation method developed by us in an earlier X-ray experiment was tested for its usefulness in chemical mutagenesis work, specifically in the prescreening for germinal point mutations. In order to explore possible parallelisms, the 7 compounds chosen for study, as well as the genetic markers used, were those with which large-scale specific-locus mutation-rate experiments in germcells had been conducted in the past or were in progress. From 1--3 dose levels were tested for each compound. On day 10 1/4 after copulation of C57BL females with T males, a single injection of the test compound was administered, and about 2000 offspring altogether were subsequently scored for survival, morphology, and presence of spots of various types. In accordance with our earlier results we found 3 types of spots: white near midline ventral spots (WMVS) which probably result from killing of melanocyte precursor cells; spots resulting from misdifferentiation; and the remainder, which probably result from expression of the recessive by one of several mechanisms (RS). Induction of teratogenic effects, which were stage-specific rather than agent-specific, generally paralleled induction of WMVS's. Both are interpreted as resulting from cell killing. Induction of RS's did not always parallel induction of WMVS's, but roughly paralleled relative frequencies of specific-locus mutations induced in spermatogonia by the same compounds. Even though the in vivo somatic-mutation method probably detects genetic changes additional to point mutations, the results indicate that it may be a useful prescreen for germinal specific-locus mutations, provided care is taken to distinguish between the 3 types of spots, only one of which (RS) is indicative of expression of the recessive.

A teratogenicity study with amaranth in cats

Cats of heterogeneous stock and in good health were given daily oral doses of 92, 187, or 264 mg amaranth/kg/day for a time period extending from 0–22 days before the onset of gestation to Days 61–62 of gestation (mean gestation period = 65 days). The pregnancies were timed by having controlled copulation of females that were in an estrous state which occurred spontaneously or was stimulated by gonadotropin treatment. Cesarean section was performed on Day 61 or 62 of gestation. Maternal values including body weight gain, number of corpora lutea, and incidences of pregnancy, abortion, and nonpregnancy showed no amaranth-related adverse effect. There was no evidence of embryotoxicity as evaluated from the data on total implants, ratio of corpora lutea to total implants, dead fetuses, deciduomas, live fetuses, 24-hr viability of the live fetuses in an incubator, mean live fetal weight, sex ratio of live fetuses, and fetal anomalies.

Some Notes on Maize Stemborers in Nigeria1

Emergence of moths of Busseola fusca Fuller and Sesamia calamistis Hampson was influenced by the onset of darkness. Most of these moths emerged at about 7 pm, nearly an hour after sunset, and continued until about 10 pm. Copulation appeared to induce female stemborer moths to oviposit readily, uniformly, and within a few days. Unmated moths laid fewer eggs, and these erratically. Copulation of unmated females after a period of up to 4 days after emergence did not significantly affect the fecundity of females. In both B. fusca and S. calamistis there was only a slight difference between the longevity of the unmated male and female moths. Mated moths, especially the females, had a shorter life span, probably because of activities involved in mating and oviposition.