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PubMed2001

Methylation is involved in the Ustilago maydis mating response.

Methionine auxotrophs of Ustilago maydis were deficient in mating; unlike wild-type cells, they neither induced nor produced normal mating filaments in the presence of compatible cells. The deficiency was most severe when cells were located some distance apart, but when in direct contact with compatible cells methionine auxotrophs mated and infected plants fairly normally. The mating deficiency was genetically linked to the methionine auxotrophy, segregating with it through in planta crosses. Wild-type cells exposed to the methyltransferase inhibitors ethionine and homocysteine thiolactone were similarly impaired in mating. Exogenous methionine, S-adenosylmethionine (SAM), synthetic mating pheromone, or cAMP all compensated for the mating impairment of the auxotrophs to some extent. Although SAM-dependent methylation could influence activities of various molecules in diverse pathways, these observations indicate that the most likely cause of the mating deficiency in met(-) cells is failure to methylate a component of the U. maydis pheromone signal transduction pathway.

Cyclic AMP↗

PubMed1998

The Fixed Sample Search Rule and Use of an Indicator Character to Evaluate Mate Quality.

The phenotypic correlation observed between mated males and females is a direct result of the decision rules that individuals employ during search for a mate. We generalise the fixed sample search rule and examine how the functional relationship between a male indicator character and the fitness benefit of a mating decision influences female search behaviour. If the phenotypes of males and females combine additively to influence the benefit of a mating decision and fitness is a highly inclined function of phenotypic values the optimal value of n, the number of males that females sample during search, is relatively large. The phenotype of the searcher has no impact on the optimal value of n if fitness is a linear function; the optimal n increases with the phenotype of females if the fitness function is convex; and a concave fitness function induces females with high trait values to sample relatively few males. Because females that sample many potential mates are expected to encounter a male with a high expression of the indicator trait linear, convex and concave fitness functions induce a random, assortive and disassortative combination of phenotypes between mated individuals, respectively. Thus, the fixed sample research tactic can produce the variety of phenotypic correlations observed between mated individuals in natural systems and our ability to derive rule-specific predictions of search behavior may generally require information on how characters used to evaluate potential mates are related to fitness.Copyright 1998 Academic Press

Journal Article↗

PubMed1976

The behavioral phenotype and mating behavior of two inbred strains of Drosophila melanogaster.

Time to copulation was measured in matings within and between two inbred Drosophila melanogaster strains, Edinburgh (E) and 6C/L, using groups of one or five flies of each sex. The E males, which mated faster, usually mate with E females, which are less likely to be fertilized and have fewer progeny whose adult viability is lower. Although generally E males mated far faster with E females than did 6C/L males, there was no difference between the males when with 6C/L females. This need not imply any mating discrimination by E females, but only differences between the strains in the use of preening as a general repulsion movement toward other flies. It is suggested that a greater variety of behavioral and other characteristics (the "behavioral phenotype") should be considered in studies of mating speed and assortative mating, especially where mating speed is being considered as a major component of fitness.

Animals↗

PubMed1978

Influence of beta-alanine on mating and territorialism in Drosophila melanogaster.

Effects of beta-alanine on mating behavior and aggression were studied in Drosophila melanogaster using the following competitive pairs: (1) homozygous black (b/b) flies, in which beta-alanine synthesis is decreased, vs. alanine is blocked vs. wild-type (e+/e+) flies; (2) dark flies, in which beta-alanine incorporation is reduced, owing mainly to chromosome 3, vs. light flies collected from the same population as were the dark flies; (3) homozygous black (b/b) flies, in which beta-alanine synthesis is decreased, vs. beta-alanine-infected b/b flies, which are phenocopies of wild-type flies. The behavior of mixed-sex groups was studied in a large, illumination-graded observation chamber containing food and in small uniformly illuminated cells also containing food. The relative competitive mating abilities of these types were measured in both experimental conditions. Uninjected black flies, but not injected ones, showed weak and unsteady gait and weak wing extension. In ebony these abnormalities were more extreme. Dark flies did not show these abnormalities. Accelerated sexual maturation was indicated in males by early onset of courtship and enhanced territorial aggression and in females by earliness of mating. Such acceleration was observed in ebony and dark flies, compared with light flies, and among beta-alanine-injected b/b flies competing with uninjected black flies. Ebony males, although maturing earlier than wild-type males, were less successful than wild-type males in mating. This difference was even greater when the flies were all allowed to mature before competing. Ebony females outmated wild-type females. Dark flies outmated light flies, and beta-alanine-injected b/b males outmated uninjected black males, especially in bright light. Ebony flies mated much longer than wild-type flies, and black flies mated slightly longer than injected b/b flies. There was some spatial isolation of ebony from wild type, dark from light, and beta-alanine-injected from uninjected b/b flies in the illumination-graded observation chamber. Ebony flies more than wild type concentrated near food. Flies were attracted to the current of moist inlet air. They were also attracted to deposited excrement, and males defended such deposits as a mating area, thus showing rudiments of arena behavior in which a mating area away from the oviposition site is defended. Usually, however, the defended area focused on food.

Aggression↗

PubMed1979

Inbreeding and heterogamic mating: an alternative to Averhoff and Richardson.

An alternative explanation to the pheromonal control of mating through chemoreceptor saturation proposed by Averhoff and Richardson (1974) is offered for the apparent rise in heterogamic mating in their experiments, after several generations of full-sib mating. In a multiple-choice mating between two genotypic strains differing in their level of sexual vigor, there is a sequence from heterogamic to homogamic mating. It is proposed that, by reducing mating speed, inbreeding changes the rate of this sequence but not its pattern, so the apparent level of heterogamic mating will increase during inbreeding, for a fixed observation period. This hypothesis was tested using the Kence-Bryant model of mating success.

Animals↗

PubMed1993

Neonatal vestibular stimulation and mating in cerebellar mutants.

Two cerebellar mutants, staggerer and reeler, and their congenic nonmutants were used in this experiment. Experimental animals were subjected to intense rotational stimulation on a tilted plane during the first 3 weeks of life, while controls were left nonstimulated. The capacity for mating, as evidenced by vaginal plugs or the occurrence of pregnancy, was assayed during two periods: between 36 and 89 days of age (Experiment A) and between 90 and 120 days of age (Experiment B). During Experiment A the mutants as well as the normals were caged inter se with partners of the opposite sex. During Experiment B the animals were caged with intact, sexually experienced partners. The animals were examined daily for evidence of mating. During Experiment A, only 3 of the 89 couples participating in this study showed evidence of mating. During Experiment B, the number of males of both strains which had mated increased significantly. The staggerer females showed a relatively high level of mating activity, whether stimulated or not. The reeler females, in contrast, rarely mated, although early stimulation significantly increased the level of sexual efficiency. The majority of the normal males and females mated, whether stimulated or not. It was concluded that massive motor-sensory stimulation in infancy, improving gait and body balance in staggerer and reeler mice, may also improve mating efficiency.

Animals↗

PubMed1991

Non-random mating between Boophilus microplus and hybrids of B. microplus females and B. annulatus males, and its possible effect on sterile male hybrid control releases.

When Boophilus microplus and Type-II hybrids (B. microplus females X B. annulatus males) were released simultaneously onto bovine hosts, mating between the two forms appeared not to be at random. There were more contypic and fewer intertypic matings than predicted under an assumption of panmixia. An examination of the patterns of matings revealed that more of the matings on the first two days of detachment were between the two sexes of B. microplus. Engorged females dropping on the last four days of maximum female detachment were predominantly hybrids mated to both B. microplus and hybrid males. The non-random mating pattern does not appear to be caused by assortative mating between B. microplus and Type-II hybrids, but because the B. microplus were competent to mate two days before the hybrids and the B. microplus males compete for males of both types better than the Type-II males.

Animals↗

PubMed2005

Mating behavior of a flower-visiting longhorn beetle Zorion guttigerum (Westwood) (Coleoptera: Cerambycidae: Cerambycinae).

Long-range sex pheromones have been demonstrated for several cerambycid beetle species. Our field study on the mating behavior of Zorion guttigerum, on the basis of its temporal and spatial distributions on mating and feeding sites (flowers), and longevity, however, suggests that such pheromones are not used by this species. Plant characteristics rather than long-range sex pheromones may play an important role in bringing both sexes together. Adult activities on flowers occur exclusively during the day with two peaks, one around midday and the other in the late afternoon. Overall operational sex ratio is male-biased ( approximately 1 female symbol:1.5 male symbol) but it becomes very highly male-biased ( approximately 1 female symbol:9 male symbol) when mating and feeding activities decrease to the minimum in mid-afternoon, suggesting that females leave flowers to oviposit during that period of time. For cerambycid species whose females oviposit alone, and in which mating and oviposition occur on different plants or different plant parts, the operational sex ratio appears to vary significantly over time on the mating sites. The number and duration of pair-bondings also vary over time for Z. guttigerum. Fewer and shorter pair-bondings in the morning may suggest a strong sexual selection process. After approximately 2 h of selection, both sexes tend to engage in longer pair-bondings and mate more times before females leave the mating sites in mid-afternoon. Details of the mating behavior are described here.

Animal Feed↗

PubMed2005

Mating behaviour in a slave-making ant, Rossomyrmex minuchae (Hymenoptera, Formicidae).

The mating behaviour of the ant Rossomyrmex minuchae, a rare, protected slave-making species in Spain, seems to be significantly affected by its particular life history and patchy habitat. The mating behaviour of the entire genus Rossomyrmex is virtually unknown. We present here the results of a 3-year study of mating behaviour in R. minuchae.Behavioural observations and limited nest excavations revealed that R. minuchae does not produce sexuals every year, the number of sexuals is low, and the sex ratio tends to be female biased. Females typically exhibit two distinct activity periods. The first, the mating period, takes place in early afternoon: the ants "call" near the natal nest, mate and then return to their nest. The second, the dispersal period takes place in late afternoon: the mated females exit their nest and fly in search of a new, non-parasitized Proformica longiseta host nest. Males are highly active during the mating period, but will remain inactive in the dispersal period even if experimentally presented with virgin females. It appears that females are monogamous, while males are polygamous. When males are late arriving at the female calling site, the females will frequently congregate presumably calling in chorus. The low reproductive efficiency exhibited by R. minuchae, coupled with the postulated low genetic variation in the population, as sisters may mate with the same male, could result in a low survival rate and risk of eventual extinction. The observed decrease in nest density we observed during the 2004 season may be indicative of such a process.

Animals↗

PubMed1992

Sexual dimorphism in the effects of mating on the in vitro release of LHRH from the ferret mediobasal hypothalamus.

A sexually dimorphic pattern in the secretion of luteinizing hormone (LH) has previously been shown to occur in response to mating in an induced ovulating species, the ferret, with mating augmenting the secretion of LH in females but not in males. The aim of this study was to determine whether this dimorphic pattern in the postcoital secretion of LH reflects a dimorphic effect of mating on the neural release of luteinizing hormone releasing hormone (LHRH). The effect of mating on the in vitro release of LHRH from mediobasal hypothalami (MBH) collected from breeding male and female ferrets was studied. Luteinizing hormone releasing hormone release and content were significantly reduced in tissues from estrous females sacrificed 0.25 h after mating compared to unpaired estrous females and estrous females sacrificed 1 or 2.6 h after the mating stimulus. By contrast, the release of LHRH from MBH fragments and LHRH tissue content were equivalent in breeding males that were sacrificed 0.25 h after mating and in breeding males that were left unpaired. These data suggest that the postcoital surge of LH in the female ferret is preceded by a release of LHRH that initially depletes neuronal terminals within the MBH, whereas LHRH release, like pituitary LH secretion, is minimally affected by mating in males.

Animals↗

PubMed1989

Mating increases plasma levels of prostaglandin F2 alpha in female garter snakes.

Plasma levels of prostaglandin F2 alpha (PGF2 alpha) in female red-sided garter snakes (Thamnophis sirtalis parietalis) were measured at intervals after mating or exposure to males. PGF2 alpha levels increased significantly within 15 minutes of mating and peaked 6-24 hr after mating. Females that did not mate, but received similar amounts of male courtship, had levels of PGF2 alpha significantly lower than those of females that mated. These results extend previous findings that unmated female garter snakes injected with PGF2 alpha exhibit sexual behavior characteristic of females that have mated. Together these data indicate that female garter snakes elaborate PGF2 alpha in response to stimuli associated with mating and that PGF2 alpha has a functional role in inducing post-mating declines in sexual behavior of this species.

Animals↗

PubMed1985

Secretory immunoglobulin binding to bacteria in the mouse uterus after mating.

Bacteria of several species were present in the mouse uterus on the morning after mating, as demonstrated by bacterial cultures and microscopic examination of Gram-stained uterine luminal contents. The similarity between bacteria cultured from the vagina before mating and from the uterus after mating suggested that bacteria were introduced into the uterus from the vagina, possibly by coitus. The bacteria were cleared from the uterus about two days after mating. Immunohistochemical labeling of smears of the luminal contents on the morning after mating demonstrated IgA, IgG, and possibly IgM bound to many of the bacteria. The bacteria were often agglutinated, and there was a correlation between the intensity of immunoglobulin labeling on bacteria and the extent of agglutination. The amount of antibody bound to bacteria in multiparous mice was about the same as in mice that had not been mated previously. We observed both IgG and IgA on bacteria when organisms from vaginal cultures were incubated for 60 min in the uteri of estrogen-primed, virgin, female mice. This indicated that the uterus was the source of at least part of the immunoglobulins bound to bacteria. We did not demonstrate that the immunoglobulins bound to bacteria were specific anti-bacterial antibodies, but the binding persisted through three washing steps and there was no immunoglobulin binding to sperm in the same preparations. Neutrophils in the uterine lumen on the day after mating contained phagocytosed bacteria. These results suggest that the secretory immune system in the female mouse reproductive tract may play a role in returning the uterus to an aseptic state after mating by at least three mechanisms: direct blocking of attachment sites involved in bacterial binding to mucosal epithelium, agglutination of bacteria and thus reduction in the number of organisms available for binding to the epithelium, and opsonization of bacteria for phagocytosis by neutrophils.

Animals↗

PubMed2004

Projection from the ventral bed nucleus of the stria terminalis to the retrorubral field in rats and the effects of cells in these areas on mating in male rats versus gerbils.

This research identified the rat counterpart of the lateral cell group of the sexually dimorphic area (SDA) found in medial preoptic area (MPOA) gerbil of gerbils. The lateral SDA (lSDA) is critical for mating in male gerbils and contains most of the SDA cells projecting to the retrorubral field (RRF), a projection that is also important for mating. Therefore, to locate the counterpart of the lateral SDA, we traced the inputs to the rat RRF, which were dense in the ventral part of the bed nucleus of the stria terminalis (BST). To determine if the ventral BST or its projection to the RRF affects mating in male rats, we disrupted them bilaterally by placing cell-body lesions bilaterally in the ventral BST or unilaterally there and in the contralateral RRF. We also studied the effects of RRF lesions in both rats and gerbils. Bilateral ventral BST lesions, which left the medial preoptic nucleus intact, produced persistent and severe mating deficits. Disconnecting the ventral BST from the RRF also had long-lasting, but less severe, consequences. RRF lesions produced only temporary mating deficits in rats, but virtually eliminated mating in gerbils. The recovery of mating in rats after RRF, but not ventral BST, lesions, and the intermediate effects of disconnecting these areas from each other suggest that the ventral BST may contain mating-related projection neurons other than those projecting to the RRF or that its RRF-projecting cells send collaterals to another site. In either case, the pedunculopontine tegmental nucleus or raphe nuclei may be involved.

Animals↗

PubMed2004

The effects of mating stimulation on c-Fos immunoreactivity in the female hamster medial amygdala are region and context dependent.

During mating in hamsters, both tactile and nontactile sensory stimulation experienced by the female affect sexual behavior and progestational neuroendocrine reflexes. To test the interactions of these types of mating stimulation, c-Fos immunohistochemistry measured brain cellular activity during sexual behavior under conditions that included combinations of tactile and nontactile mating stimulation. Test groups received: (1) mating stimulation from a male, females being either fully mated or mated while wearing a vaginal mask, or (2) experimenter applied manual vaginocervical stimulation (VCS)-with or without males present, or (3) handling similar to VCS but without insertions-with or without males present. Numbers of c-Fos immunoreactive cells were counted in specific subdivisions of the posterior medial amygdala (MeP) and ventromedial hypothalamus (VMH). The medial amygdala dorsal and ventral subdivisions responded differentially to components of mating stimulation. The posterodorsal Me (MePD) cellular activation was greatest during mating conditions that included VCS and/or males present. However, the posteroventral Me (MePV) was sensitive to male exposure and not to VCS. Also, MePV and VMH shell responses mirrored each other, both being primarily sensitive to male exposure. In separate tests, manual VCS induced pseudopregnancy, though the procedure was most effective with additional nontactile stimulation from males present. In summary, contextual cues provided by nontactile male stimulation enhance the effect of vaginocervical and other tactile stimulation on reproductive processes. Furthermore, c-Fos expression in the female hamster medial amygdala is region and context dependent.

Amygdala↗

PubMed1999

Chemical communication and mate attraction in echinostomes.

Mate attraction is widespread among animals and appears to facilitate mating and to prevent hybridisation between closely related species. In this study we investigated mate preference between two geographical isolates of Echinostoma caproni (Trematoda, Platyhelminth) and another species of the genus Echinostoma E. sp. Because previous experiments showed a partial reproductive isolation between echinostome isolates, we examined the possibility that such isolation resulted from differential mate attraction. We compared intra-isolate, inter-isolate and interspecific pairings using two in vitro experimental designs. In the first experiment we compared mate attraction of two individuals belonging to or not belonging to the same isolate, while in the second experiment we examined mate choice when individuals were in the presence of individuals from both the same isolate and from a different isolate or a different species. Distances between worms were measured over a period of 90 min. Results from both experiments suggested that mate attraction was similar for intra-isolate, inter-isolate or interspecific combinations. This lack of mate preference in vitro would therefore support an alternative hypothesis of a reproductive isolation through sperm selection.

Animals↗

PubMed2003

Costs of mating and egg production in female Callosobruchus chinensis.

Costs of reproduction include the costs of mating and egg production. Specific techniques such as irradiation or genetic mutation have been used to divide the expense into costs of mating and egg production in previous studies. We tried to divide the costs in the adzuki bean beetle, Callosobruchus chinensis (Coleoptera: Bruchidae), which needs some kinds of bean as an oviposition substrate. Mated females that were not allowed to lay eggs had a shorter life span than virgin females, but they had a longer life span than mated females that were allowed to lay eggs. The results showed two independent significant costs, mating and egg production, on the life span in C. chinensis. Costs of mating, however, include the costs of sexual harassment by males and copulation itself, and we need further studies to divide the costs. The present method for dividing the cost of reproduction into costs of mating and egg production can be applied to a broad taxonomic range of insect species, and thus it will be a useful model system for inter-specific comparisons of costs of mating and egg production.

Animals↗

PubMed1999

Ecdysteroid titers in mated and unmated Drosophila melanogaster females.

Radioimmunoassay was used to determine ecdysteroid titers in mated or unmated Drosophila melanogaster females. Whole-body ecdysteroid titers increase after mating and this response is more pronounced after 12-24 hours than it is immediately after mating. In one experiment, females were mated to transgenic males deficient in accessory gland proteins to test whether these peptides mediate the observed increase in female whole-body ecdysteroid titers. Females mated to such transgenic males do not show a pronounced increase in whole-body ecdysteroid titers. The effect of mating on female hemolymph ecdysteroid titers was also investigated. Hemolymph ecdysteroid titers decrease after mating. The ecdysteroid titer change in the hemolymph may result from yolk protein uptake of ecdysteroids into developing vitellogenic oocytes as a consequence of male accessory gland protein stimulation of female oocyte maturation and yolk protein synthesis following mating.

Journal Article↗

PubMed1988

The evolution of mate choice in a fluctuating environment.

This paper analyzes the evolutionary dynamics of a locus controlling the degree of female mating preference in a temporally fluctuating environment. Preference for mating with males with respect to their genotypes at a locus that is subject to temporally varying natural selection pressure is considered first. With weak selection and free recombination between the choice locus and the selected locus, preference for mating with heterozygotes appears to be favored. With strong selection, preference for homozygous mates may be favored. In each case, choice alleles may increase from very low initial frequencies to near fixation, in contrast to previous models of mate choice in varying environments. Linkages between the two loci has complex effects on the strength and direction of selection for mate choice. Preference for mating with males with the currently fitter genotypes at the locus under natural selection is also modelled. Provided that the environmental period is not too short, a rare allele conferring such preference may be favored and spread to fixation. Strong natural selection, tight linkage and a short environmental period may produce polymorphism for the level of mate choice.

Alleles↗