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A pheromone found in the males of some species of Hypsoblennius apparently facilitates male courtship by releasing sexual appetitive behavior and by increasing sexual receptivity.
Mating behavior of the subterranean mole rat, Spalax ehrenbergi, consists of three distinct stages-agonistic, courtship, and copulation. Spalax sexual behavior reflects certain cricetid affinities, some features general in rodents, and others presumably related to its subterranean, territorial life. Within four groups of Spalax ehrenbergi, each with different numbers of chromosomes, recently found in Israel, mating behavior seems to provide partial reproductive barriers. Selective matings between chromosome forms may complement a cytologic isolating mechanism to prevent widespread natural hybridization.
A questionnaire designed to measure psychological abuse and kindness was responded to by 90 college women involved in dating relationships. Analysis indicated that, while many relationships were low abuse/high kindness, a substantial number were characterized by high abuse/low kindness, high abuse/high kindness and low abuse/low kindness. An analysis of these different categories of dating relationships as well as explanations as to why young women should be in such negative relationships are included. The study also indicated significant differences between women's reports of feelings and behaviors. Finally, a comparison of past versus present relationships showed proportionately few significant differences in behaviors but many significant differences in feelings. The major finding, that some college women are in dating relationships characterized by psychological abuse, was explored, and comparisons to the literature on wife abuse and courtship violence were also included.
This research is an investigation into the cognitive aspects of mate attraction in human males. Two experiments demonstrate that visual exposure to women (in person or within photographs) can prime large changes in the attitudes, mood states, and personality trait descriptions of male participants. These changes, furthermore, are such that participants show greater conformity to female mate preferences as described in the extant literature: In particular, men exposed to potential mates reported higher valuations of material wealth, greater momentary feelings of ambition, higher valuations of other indicators of social status, and personality trait descriptions indicative of high surgency/extraversion. All such effects occurred without participants' awareness that their responses had been affected by the experimental manipulations. These findings suggest a model of mate attraction mechanisms in which input cues from potential mates can prime those psychological representations that facilitate the behavioral expression of courtship tactics.
Analysis of criminal proceedings and death records for early modern Geneva reveals an explosion in suicides after 1750. New attitudes toward courtship, marriage, and the familly contributed to this dramatic increase, as unprecedented numbers of people took their lives because of family concerns, such as marital breakdown, unhapppy love stories, and deaths of family members. Greater interest in the companionate marriage was central to these changes. After 1750, marriage, even more than parenthood, offered immunity to suicide, as married people were underrepresented among those who took their lives. Although men constituted the large majority of suicides, women and men shared the growing emphasis on conjugal sentiment, which cut across class lines.
A heterosexual community can be analyzed as a marketplace in which men seek to acquire sex from women by offering other resources in exchange. Societies will therefore define gender roles as if women are sellers and men buyers of sex. Societies will endow female sexuality, but not male sexuality, with value (as in virginity, fidelity, chastity). The sexual activities of different couples are loosely interrelated by a marketplace, instead of being fully separate or private, and each couple's decisions may be influenced by market conditions. Economic principles suggest that the price of sex will depend on supply and demand, competition among sellers, variations in product, collusion among sellers, and other factors. Research findings show gender asymmetries (reflecting the complementary economic roles) in prostitution, courtship, infidelity and divorce, female competition, the sexual revolution and changing norms, unequal status between partners, cultural suppression of female sexuality, abusive relationships, rape, and sexual attitudes.
Courtship behavior and reproductive isolation between nine strains of Drosophila lini and its siblings from Taiwan (TWN), Dinghushan (DHS) and Nankunshan (NKS) in China, and Pyinoolwin (MMY) and Yangon (RGN) in Myanmar were investigated. No premating and postmating isolation between the Taiwan and mainland China strains were found. Crosses between mainland China (DHS and NKS) or the TWN strain and the MMY or RGN strain produced fertile F1 hybrid females and sterile F1 hybrid males. Crosses between MMY strains and RGN strains which showed strong premating isolation produced either no F1 hybrids, or fertile F1 hybrid females and sterile males in some cases. These results suggest the existence of at least three genetically distinct sibling species of D. lini.
Previous laboratory studies have demonstrated that estrogenic and antiandrogenic chemicals can alter several sexual characteristics in male poeciliid fishes. Whether similar disturbances occur under field conditions remains to be confirmed. Lake Apopka, Florida, is contaminated with numerous chemicals, some of which possess endocrine-disrupting activity. Male mosquitofish (Gambusia holbrooki) were collected monthly from December 2000 through May 2001 from Lake Apopka and two nearby reference lakes, Orange Lake and Lake Woodruff National Wildlife Refuge. Selected sexual characteristics were compared temporally and among lakes during the collection period. Male fish from Lake Apopka had slightly shorter gonopodia and on average 32 and 47% fewer sperm cells per milligram testis, when compared with the fish collected from Orange Lake and Lake Woodruff, respectively. The testes weights increased markedly during spring, with significantly smaller testes in fish from Lake Apopka than from Orange Lake, but surprisingly, the smallest testes occurred in males obtained from the Lake Woodruff population. The highest liver weights were found in the Lake Apopka population. Whole-body concentrations of testosterone and estradiol varied among months; the peak testosterone concentration occurred in January and was significantly lower in male fish from Lake Apopka compared with Orange Lake. The intensity of male courtship behavior was highly correlated to body testosterone concentration, but no statistically significant differences in sexual behavior among the lakes were found. We conclude that sexual characteristics of relevance to male reproductive capacity are altered in the Lake Apopka mosquitofish population, and we discuss the presence of chemicals with antiandrogenic effects in Lake Apopka as a possible cause of the observed alterations.
Based on a design used in previous research with heterosexuals, this study assessed the permanent partner priorities of gay and straight men and women, as well as the perception of those priorities by each gender and sexual orientation. Heterosexuals and homosexuals did not differ in their rank-ordered priorities, but tended to misperceive the priorities of their own and the other groups studied. Differentials of misperception were explained by varying societal pressures experienced by homo- and heterosexual men and women. Implications based on the difference between the competitive nature of courtship and the cooperative nature of permanent pairing were drawn from the findings.
The structures and functions of many genes are homologous in Drosophila and humans. Therefore, studying pathological processes in Drosophila, in particular neurogenerative processes accompanied by progressive memory loss, helps to understand the ethiology of corresponding human disorders and to develop therapeutic strategies. It is believed that the development of neurogenerative diseases might result from alterations in the functioning of the heat shock/chaperone machinery. In view of this, we used Drosophila mutant l(1)ts403 with defective synthesis of heat shock proteins for studying learning and memory in a test of conditioned courtship suppression following a heat shock given at different developmental stages. High learning indices were registered immediately and 30 min after training both in the intact controls and in flies subjected to different developmental heat shocks. This indicated normal learning and memory acquisition in the mutant. At the same time, memory retention (3 h after training) suffered to different extent depending on the developmental stage. The remote effects of heat shock given during the formation of the mushroom bodies indicated the important role of this brain structure in the memory formation. The observed memory defects may result from alterations both in mRNA transport and in the functions of molecular chaperones in the l(1)ts403 mutant.
A trend for larger males to obtain a disproportionately high number of matings, as occurs in many animal populations, typically is attributed either to female choice or success in male-male rivalry; an alternative mechanism, that larger males are better able to coercively inseminate females, has received much less attention. For example, previous studies on garter snakes (Thamnophis sirtalis parietalis) at communal dens in Manitoba have shown that the mating benefit to larger body size in males is due to size-dependent advantages in male-male rivalry. However, this previous work ignored the possibility that larger males may obtain more matings because of male-female interactions. In staged trials within outdoor arenas, larger body size enhanced male mating success regardless of whether a rival male was present. The mechanism involved was coercion rather than female choice, because mating occurred most often (and soonest) in females that were least able to resist courtship-induced hypoxic stress. Males do physically displace rivals from optimal positions in the mating ball, and larger males are better able to resist such displacement. Nonetheless, larger body size enhances male mating success even in the absence of such male-male interactions. Thus, even in mating systems where males compete physically and where larger body size confers a significant advantage in male-male competition, the actual selective force for larger body size in males may relate to forcible insemination of unreceptive females. Experimental studies are needed to determine whether the same situation occurs in other organisms in which body-size advantages have been attributed to male-male rather than male-female interactions.
Injections of progesterone induce incubation behavior in gonadally intact ring doves only if the doves have had previous experience with at least the nest-building phase of a breeding cycle. The present study was designed to determine whether exposure to progesterone during the nest-building phase is sufficient to account for the ability of progesterone to induce incubation at a later time or whether some other factor provided by experience with this phase of the cycle is needed. Six groups of 10 pairs of doves each were provided with different combinations of experience and progesterone priming. Progesterone priming combined with social isolation or with courtship experience had no significant effect on subsequent progesterone-induced incubation. However, doves that participated in the nesting phase of the cycle during progesterone priming later incubated in response to progesterone treatment. Nesting activity, which may or may not include building the nest, seemed to be the relevant experience.
This study investigated the effect of family structure on previous dating behavior of older adolescents, and examined the relationship of family structure, family relationship variables, and personal attributes to previous dating behaviors. Data were obtained from 96 males and 81 females enrolled in human development courses at two midwestern universities; 122 were from intact, nuclear families and 55 were from nonintact families. The Dating and Courtship Behavior Questionnaire, adapted from questionnaires by Winch (1949a) and Landis (1963), was administered to subjects during regular class periods. Family structure did not have an effect on number of partners or steadies, but adolescents from nonintact households began dating at younger ages than those from intact households. Personal attributes were more often related to dating behaviors than family structure or family relationship variables. Little support was found for the proposition that dating behaviors were affected by family structure.
As part of a study of sexual behavior in 6 species of closely related and often sympatric cockroaches, interspecific interactions among the various species were examined. To some degree males of nearly all species court females of a second species. Females almost always rejected these courtship attempts. Experimental evidence indicates that the volatile female sex pheromone of each species is attractive to males of most of the other species. Rejection of heterospecific males appears to be due to species specific male pheromones. These pheromones also appear to mediate the formation of homospecific clusters of courting males in time or space.
OBJECTIVE: To understand social preferences for thinness and the stigmatization of obesity, this study examined attitudes of adolescents towards dating (courtship) of overweight people. DESIGN: A cross-sectional survey was performed in upper class high school students at a public and private school. MEASUREMENTS: A written questionnaire that included questions assessing attitudes about dating overweight individuals, including a Guttman Dating Overweight Partners Scale (DOPS), was completed by 786 students. RESULTS: Women were more concerned than men about their own body weights, while men emphasized thinness in partners more than did women. The DOPS scale revealed low comfort in engaging, in dating activities with very overweight partners, moreso by men than by women. CONCLUSION: Stigmatization of overweight students in dating activities may be an important influence on desires of adolescents to be thin to be attractive.
Steroid-sensitive, vocal courtship behavior is a function of a specific, hypothalamic nucleus, the sexually dimorphic area pars compacta (SDApc) in the male adult gerbil. Gender-related differences in the number of neurons in this nucleus are evident immediately after birth. By using unbiased stereological estimates of cell numbers in Nissl-stained, paraffin-wax sections of brain, we investigated the mechanisms differentiating cell number between the sexes in the SDApc on postnatal days 0, 3, 6, and 15. Cell death, identified by pyknosis, was greatest in the SDApc between days 0-3 in males, whereas in females, maximum values were reached between days 3-6. Similarly, the ratio of pyknotic to normal neurons peaked between days 0-3 in males and 3-6 in females but then declined in both sexes. Pyknotic cells were seldom seen in either sex by day 15. Morphological characteristics of apoptosis including chromatin condensation, cell fragmentation, and ingestion of apoptic bodies by macrophages were all demonstrated by transmission electron microscopy. Macrophages showed specific morphological characteristics of microglia. Cell division (mitosis) was identified in the SDApc during postnatal days 0, 3, and 6 but the numbers of mitotic figures were low, negligible on day 15, and similar between the sexes. These results demonstrate that cell death and proliferation occur simultaneously in the neonatal gerbil brain. The stereological estimates of cell death in the developing SDApc indicated a lower incidence of neuronal death occurring earlier in males than in females.
Differences in the sizes of sensory and neural structures are used as an indication of differences in the function of those structures. Large VNOs often are interpreted to mean that this sense is particularly important in the life history of the animal. They also are assumed to be associated with more primitive animals. I examined VNO sizes across mammalian, reptilian, and amphibian lineages while attempting to account for total body size, because VNO and total body sizes are related. Most descriptions of VNO size and development are not quantified and often ambiguous. Large VNOs in a lineage should not be interpreted necessarily as primitive. Comparisons across smaller taxonomic ranges are easier to interpret. Plethodontid salamanders are a diverse set of species for which VNO descriptions show trends in size associated with habitat, sex, and season. Semiaquatic species tend to have proportionately larger VNOs than terrestrial species, males have larger organs than females, and VNOs can show increases and decreases in size that may be associated with seasonal activities. Salamanders may use their VNOs to locate and identify mates, as part of the courtship sequences, or to identify and assess neighboring territory holders.
Although female common marmosets typically do not breed while housed with their natal families, up to half ovulate at least once while housed with the intact natal family, and a similar proportion conceive if an unrelated adult male is present in the group. In this study, we investigated the behavioral and social correlates of escape from suppression of ovulation by daughters housed in intact natal families or in families in which the father had been replaced by an unrelated adult male. Focal-animal behavioral data were collected from daughters that were (N = 7) or were not (N = 10) undergoing ovulatory cycles while housed with the natal family and from daughters that were (N = 5) or were not (N = 3) cycling or pregnant in families containing an unrelated male. Additionally, four cyclic and six acyclic females housed in intact natal families underwent simulated "prospecting" tests. Cyclic and acyclic daughters in intact natal families did not engage in sexual interactions with the father and showed few differences from one another in their interactions with the parents. Moreover, cyclic and acyclic daughters did not differ in their willingness to leave the family for short periods or to investigate an unfamiliar family in "prospecting" tests. However, daughters that underwent ovarian cycles in the presence of an unrelated male showed numerous behavioral differences from those in intact natal families, including frequent courtship and sexual behaviors with the male, reduced affiliative interactions with the mother, and elevated frequencies of aggressive display behavior. Moreover, these females were less likely to behave submissively towards the mother or the adult male. These findings suggest that both suppression of ovulation and inhibition of sexual behavior normally contribute to reproductive failure in female marmosets living with their natal families, and that the two components of suppression may become dissociated under specific social conditions.