Are men more promiscuous than women?

In spite of the unassailable logic that every new coital partner a man has is also a new partner for the woman concerned, men typically claim more sexual partners than women. If these claims are correct, can prostitutes and other hypersexual women account for this slippage? The present study examines whether the incidence of such women is sufficient to explain the discrepancy in number of lifetime partners claimed by men and women.     

Why do women live longer than men?

In the contemporary United States, males have 60 percent higher mortality than females. In Part I, published in the previous issue, we showed that 40 percent of this sex differential in mortality is due to a twofold elevation of arteriosclerotic heart disease among men. Major causes of higher rates of arteriosclerotic heart disease in men include greater cigarette smoking among men; probably a greater prevalence of the competitive, aggressive Coronary Prone Behavior Pattern among men; and possibly a protective role of female hormones. In addition, men have higher death rates for lung cancer and emphysema, primarily because more men smoke cigarettes. In Part II we analyze the other major causes of men's higher death rates: accidents, suicide, and cirrhosis of the liver. Each of these is related to behaviors which are encouraged or accepted more in men than in women in our society--for example, using guns, being adventurous and acting unafraid, working at hazardous jobs and drinking alcohol. We conclude with suggestions for reducing male mortality; for example, by changing the social conditions which foster in men the behaviors that elevate their mortality.     

Are men better than women at acoustic size judgements?

Formants are important phonetic elements of human speech that are also used by humans and non-human mammals to assess the body size of potential mates and rivals. As a consequence, it has been suggested that formant perception, which is crucial for speech perception, may have evolved through sexual selection. Somewhat surprisingly, though, no previous studies have examined whether sexes differ in their ability to use formants for size evaluation. Here, we investigated whether men and women differ in their ability to use the formant frequency spacing of synthetic vocal stimuli to make auditory size judgements over a wide range of fundamental frequencies (the main determinant of vocal pitch). Our results reveal that men are significantly better than women at comparing the apparent size of stimuli, and that lower pitch improves the ability of both men and women to perform these acoustic size judgements. These findings constitute the first demonstration of a sex difference in formant perception, and lend support to the idea that acoustic size normalization, a crucial prerequisite for speech perception, may have been sexually selected through male competition. We also provide the first evidence that vocalizations with relatively low pitch improve the perception of size-related formant information.     

Do pretty women inspire men to discount the future?

Organisms 'discount the future' when they value imminent goods over future goods. Optimal discounting varies: selection should favour allocations of effort that effectively discount the future relatively steeply in response to cues promising relatively good returns on present efforts. However, research on human discounting has hitherto focused on stable individual differences rather than situational effects. In two experiments, discounting was assessed on the basis of choices between a smaller sum of money tomorrow and a larger sum at a later date, both before and after subjects rated the 'appeal' of 12 photographs. In experiment 1, men and women saw either attractive or unattractive opposite-sex faces; in experiment 2, participants saw more or less appealing cars. As predicted, discounting increased significantly in men who viewed attractive women, but not in men who viewed unattractive women or women who viewed men; viewing cars produced a different pattern of results.     

Do men with more masculine voices have better immunocompetence?

The human voice is often considered to be a secondary sexual characteristic that signals underlying information about the immunocompetence of the speaker (i.e. the immunocompetence handicap hypothesis; ICHH). However, no studies have yet shown a relationship between vocal characteristics and biomarkers of immune function or self-reported health. In a sample of 108 men, we examined correlations between masculine vocal characteristics [i.e. relatively low fundamental frequency (F₀), low F₀ variability (F₀-SD), low formant position (P_f), and high vocal tract length (VTL)] in relation to salivary immunoglobulin-A (sIgA; a marker of mucosal immunity), testosterone (T), and well-validated measures of self-reported health status. Results showed that sIgA correlated with masculinized F₀, P_f, and VTL. Self-report health correlated with masculinized P_f and VTL. Anticipated future health correlated negatively with F₀-SD and sick role propensity (less interference of illness in daily life) correlated positively with VTL. Perceived susceptibility to infection correlated with more feminized F₀ and F₀-SD. Our results demonstrated a small relationship between men's vocal characteristics and one putative indicator of mucosal immunity along with self-identified health status. We suggest that more research is warranted to determine whether the masculinity of men's voices may serve as an indicator of their phenotypic quality.     

Do bonobos copulate more frequently and promiscuously than chimpanzees?

The copulatory activities of bonobos (Pan paniscus) of Wamba, Zaire, were compared with those of chimpanzees (P. troglodytes schweinfurthii) of Mahale, Tanzania. The copulation rates of adult male bonobos were equal to or lower than those of adult male chimpanzees. The copulation rates of adult female bonobos were approximately equal to those of adult female chimpanzees who were in maximal genital swelling, but it should be much higher than those of the adult female chimpanzees throughout the birth interval. The copulation rates of adolescent male bonobos were lower than those of adolescent male chimpanzees, whereas the copulation rates of adolescent female bonobos were much higher than those of adolescent female chimpanzees. It was suggested that the bonobos of Wamba did not copulate more promiscuously than did the chimpanzees of Mahale. The female bonobos may show “receptivity”, whereas female chimpanzees may show rather “proceptivity”.     

Do scale-free regulatory networks allow more expression than random ones?

In this paper, we compile the network of software packages with regulatory interactions (dependences and conflicts) from Debian GNU/Linux operating system and use it as an analogy for a gene regulatory network. Using a trace-back algorithm we assemble networks from the pool of packages with both scale-free (real data) and exponential (null model) topologies. We record the maximum number of packages that can be functionally installed in the system (i.e., the active network size). We show that scale-free regulatory networks allow a larger active network size than random ones. This result might have implications for the number of expressed genes at steady state. Small genomes with scale-free regulatory topologies could allow much more expression than large genomes with exponential topologies. This may have implications for the dynamics, robustness and evolution of genomes.     

Do single nodules of Casuarinaceae contain more than oneFrankia strain?

Summary Studies using inoculum suspensions prepared from single nodules of Casuarinaceae suggest that more than oneFrankia strain may be found in some nodules. Evidence is also presented to support the concept of intergeneric specificity in host-Frankia relations in the family Casuarinaceae.     

What do men want? Re-examining whether men benefit from higher fertility than is optimal for women

Several empirical observations suggest that when women have more autonomy over their reproductive decisions, fertility is lower. Some evolutionary theorists have interpreted this as evidence for sexual conflicts of interest, arguing that higher fertility is more adaptive for men than women. We suggest the assumptions underlying these arguments are problematic: assuming that women suffer higher costs of reproduction than men neglects the (different) costs of reproduction for men; the assumption that men can repartner is often false. We use simple models to illustrate that (i) men or women can prefer longer interbirth intervals (IBIs), (ii) if men can only partner with wives sequentially they may favour shorter IBIs than women, but such a strategy would only be optimal for a few men who can repartner. This suggests that an evolved universal male preference for higher fertility than women prefer is implausible and is unlikely to fully account for the empirical data. This further implies that if women have more reproductive autonomy, populations should grow, not decline. More precise theoretical explanations with clearly stated assumptions, and data that better address both ultimate fitness consequences and proximate psychological motivations, are needed to understand under which conditions sexual conflict over reproductive timing should arise.     

Do molecules matter more than morphology? Promises and pitfalls in parasites

Systematics involves resolving both the taxonomy and phylogenetic placement of organisms. We review the advantages and disadvantages of the two kinds of information commonly used for such inferences--morphological and molecular data--as applied to the systematics of metazoan parasites generally, with special attention to the malaria parasites. The problems that potentially confound the use of morphology in parasites include challenges to consistent specimen preservation, plasticity of features depending on hosts or other environmental factors, and morphological convergence. Molecular characters such as DNA sequences present an alternative data source and are particularly useful when not all the parasite's life stages are present or when parasitaemia is low. Nonetheless, molecular data can bring challenges that include troublesome DNA isolation, paralogous gene copies, difficulty in developing molecular markers, and preferential amplification in mixed species infections. Given the differential benefits and shortcomings of both molecular and morphological characters, both should be implemented in parasite taxonomy and phylogenetics.     

Do more attractive women show stronger preferences for male facial masculinity?

Researchers have suggested that more attractive women will show stronger preferences for masculine men because such women are better placed to offset the potential costs of choosing a masculine mate. However, evidence for correlations between measures of women's own attractiveness and preferences for masculine men is mixed. Moreover, the samples used to test this hypothesis are typically relatively small. Consequently, we conducted two large-scale studies that investigated possible associations between women's preferences for facial masculinity and their own attractiveness as assessed from third-party ratings of their facial attractiveness (Study 1, N = 454, laboratory study) and self-rated attractiveness (Study 2, N = 8972, online study). Own attractiveness was positively correlated with preferences for masculine men in Study 2 (self-rated attractiveness), but not Study 1 (third-party ratings of facial attractiveness). This pattern of results is consistent with the proposal that women's beliefs about their own attractiveness, rather than their physical condition per se, underpins attractiveness-contingent masculinity preferences.     

Do women with acute myocardial infarction receive the same treatment as men?

OBJECTIVE--To determine whether women with acute myocardial infarction in the Nottingham health district receive the same therapeutic interventions as their male counterparts. DESIGN--Retrospective study. SETTING--University and City Hospitals, Nottingham. PATIENTS--All patients admitted with a suspected myocardial infarction during 1989 and 1990. MAIN OUTCOME MEASURES--Route and timing of admission to hospital, ward of admission, treatment, interventions in hospital, and mortality. RESULTS--Women with myocardial infarction took longer to arrive in hospital than men. They were less likely to be admitted to the coronary care unit and were therefore also less likely to receive thrombolytic treatment. They seemed to have more severe infarcts, with higher Killip classes, and had a slightly higher mortality during admission. They were less likely than men to receive secondary prophylaxis by being discharged taking beta blockers or aspirin. CONCLUSIONS--Survival chances both in hospital and after discharge in women with acute myocardial infarction are reduced because they do not have the same opportunity for therapeutic intervention as men.     

Do the Japanese feel more suspicious about cancer registration than the British?

Background: Cancer registration is indispensable, providing useful statistical measures for the appropriate evaluation of cancer control programs and medical treatment or screening. Methods: Following the British national survey on attitudes toward cancer registration, we conducted an investigation to correctly evaluate the general opinion of the Japanese population in this regard. We randomly recruited 3000 men and women aged 20–69 years from a research database. Results: Only 4% of all respondents had heard about the cancer registry system before the investigation. However, 77% of respondents thought that cancer registration was useful. Forty-three percent of respondents answered, regardless of the strictness of the data protection, that privacy had been violated if the registration occurred without an individual explanation. Compared with the British survey results, Japanese people seemed to be more suspicious about the largely unknown system of cancer registry. Nonetheless, it is noteworthy that Japanese respondents did not show active opposition to cancer registration; they tended to choose “I don’t know” instead of “no” to questions asking if they supported the registry system. Multivariate analysis showed that male sex, older age, and living in the southern region were the factors significantly associated with support for cancer registration. Conclusions: We can seek society's understanding toward cancer registration by actively utilizing information from cancer registries, by using examples of how data are actually used that have wide appeal, and by educating the public on how the data are treated under the complete privacy policy.