Tuesday, August 24, 2021

How are gene variants associated with same-sex sexual behaviour maintained in the gene pool? New study suggests that the same variants, when found in individuals who don't engage in SSSB behavior, are associated with having more sexual partners

Genomic evidence consistent with antagonistic pleiotropy may help explain the evolutionary maintenance of same-sex sexual behaviour in humans. Brendan P. Zietsch, Morgan J. Sidari, Abdel Abdellaoui, Robert Maier, Niklas Långström, Shengru Guo, Gary W. Beecham, Eden R. Martin, Alan R. Sanders & Karin J. H. Verweij. Nature Human Behaviour, August 23 2021. https://www.nature.com/articles/s41562-021-01168-8

Abstract: Human same-sex sexual behaviour (SSB) is heritable, confers no immediately obvious direct reproductive or survival benefit and can divert mating effort from reproductive opportunities. This presents a Darwinian paradox: why has SSB been maintained despite apparent selection against it? We show that genetic effects associated with SSB may, in individuals who only engage in opposite-sex sexual behaviour (OSB individuals), confer a mating advantage. Using results from a recent genome-wide association study of SSB and a new genome-wide association study on number of opposite-sex sexual partners in 358,426 individuals, we show that, among OSB individuals, genetic effects associated with SSB are associated with having more opposite-sex sexual partners. Computer simulations suggest that such a mating advantage for alleles associated with SSB could help explain how it has been evolutionarily maintained. Caveats include the cultural specificity of our UK and US samples, the societal regulation of sexual behaviour in these populations, the difficulty of measuring mating success and the fact that measured variants capture a minority of the total genetic variation in the traits.

Popular version: Genetic patterns offer clues to evolution of homosexuality. Sara Reardon. Nature News, Aug 23 2021. https://www.nature.com/articles/d41586-021-02312-0

Acute scarcity significantly increases the propensity to engage in unethical economic behavior; find no evidence that chronic experiences of scarcity in the form of low social class affect unethical economic behavior

Material Scarcity and Unethical Economic Behavior: A Systematic Review and Meta-Analysis. Christian Elbaek, Panagiotis Mitkidis, Lene Aarøe, Tobias Otterbring. Pre-print, Aug 2021. DOI: 10.21203/rs.3.rs-800481/v1

Abstract: Individuals around the globe experience different forms of material resource scarcity in terms of aspects such as hunger, thirst, or financial strains. As experiences of material scarcity have been found to make individuals more risk-taking, impulsive, and focused on regaining resources in the short-term, a growing body of research has investigated how such scarcity affects moral economic behavior. Yet, findings remain mixed and at times contradictory, thus calling for a systematic meta-analytical review on this overarching topic. In this pre-registered systematic review and meta-analysis, we evaluate qualitatively and quantitatively how material resource scarcity affects moral economic behavior. We analyze a comprehensive dataset including 44 published and unpublished studies comprising a total of 6,921 respondents across four distinct types of material scarcity: financial scarcity, physiological scarcity, scarcity reminders, and lower social class. Our findings show that acute scarcity significantly increases the propensity to engage in unethical economic behavior (gfinancial = .24, gphysiological = .39, greminders = .32). Importantly, we find no evidence that chronic experiences of scarcity in the form of low social class affect unethical economic behavior (gsocial class = .02). These results appear robust to the influence of publication bias and contextual sensitivity. We discuss how these findings advance our understanding of the psychological and moral consequences of scarcity and elaborate on implications for public policy.

KEYWORDS: resource scarcity, socioeconomic status, morality, unethical economic behavior, meta-analysis

From 2010... Lesions and Behavior Associated with Forced Copulation of Juvenile Pacific Harbor Seals (Phoca vitulina richardsi) by Adult Southern Sea Otters (Enhydra lutris nereis)

Lesions and Behavior Associated with Forced Copulation of Juvenile Pacific Harbor Seals (Phoca vitulina richardsi) by Southern Sea Otters (Enhydra lutris nereis). Heather S. Harris et al. Aquatic Mammals Journal, 36(4), 331-341, November 29 2010. DOI: 10.1578/AM.36.4.2010.331

Abstract: Nineteen occurrences of interspecific sexual behavior between male southern sea otters (Enhydra lutris nereis) and juvenile Pacific harbor seals (Phoca vitulina richardsi) were reported in Monterey Bay, California, between 2000 and 2002. At least three different male sea otters were observed harassing, dragging, guarding, and copulating with harbor seals for up to 7 d postmortem. Carcasses of 15 juvenile harbor seals were recovered, and seven were necropsied in detail by a veterinary pathologist. Necropsy findings from two female sea otters that were recovered dead from male sea otters exhibiting similar behavior are also presented to facilitate a comparison of lesions. The most frequent lesions included superficial skin lacerations; hemorrhage around the nose, eyes, flippers, and perineum; and traumatic corneal erosions or ulcers. The harbor seals sustained severe genital trauma, ranging from vaginal perforation to vagino-cervical transection, and colorectal perforations as a result of penile penetration. One harbor seal developed severe pneumoperitoneum subsequent to vaginal perforation, which was also observed in both female sea otters and has been reported as a postcoital lesion in humans. This study represents the first description of lesions resulting from forced copulation of harbor seals by sea otters and is also the first report of pneumoperitoneum secondary to forced copulation in a nonhuman animal. Possible explanations for this behavior are discussed in the context of sea otter biology and population demographics.

Key Words: sea otter, Enhydra lutris nereis, harbor seal, Phoca vitulina richardsi, forced copulation, interspecific sexual behavior, mating trauma, pneumoperitoneum


Sexual interactions between species have been well-documented among marine mammals (Wilson, 1975; Best et al., 1981; Harcourt, 1993; Hatfield et al., 1994; Miller et al., 1996; Mortenson & Follis, 1997; Cassini, 1998; Hayward, 2003). Such behavior has occasionally been observed among pinnipeds with overlapping breeding seasons that share the same rookeries, providing ample opportunities for interaction between adult or subadult males and heterospecific females (Miller et al., 1996). Documentation of hybrid offspring within mixed colonies of otariids (Miller et al., 1996) and phocids (Kovacs et al., 1997) further supports the occurrence of breeding events between pinniped species. 

Reports also exist of interspecific sexual interactions occurring outside of the normal breeding season in which a single aggressive male opportunistically copulated with females or pups during periods when conspecific males were not present (Wilson, 1975; Best et al., 1981; Miller et al., 1996; Mortenson & Follis, 1997; Hayward, 2003). Large-scale mortality has resulted when females and juveniles were physically overpowered and forcibly copulated by much larger heterospecific males (Best et al., 1981; Miller et al., 1996; Mortenson & Follis, 1997; Cassini, 1998). In some cases, male pinnipeds have approached their subjects on land or in the water, mounted and attempted copulation (Wilson, 1975; Best et al., 1981; Harcourt, 1993; Miller et al., 1996; Mortenson & Follis, 1997; Hayward, 2003), killed the subject (Best et al., 1981; Harcourt, 1993; Miller et al., 1996; Mortenson & Follis, 1997), and then continued to guard and copulate with the carcass (Best et al., 1981; Miller et al., 1996).



The behavioral observations and lesions described in this study are extreme examples of the spectrum of mating-associated trauma observed in southern sea otters. Copulation normally occurs in the water where the male sea otter will approach the female from behind, grip her around the chest with his forepaws, and grasp her nose or the side of her face with his teeth (Kenyon, 1969; Staedler & Riedman, 1993). Females often initially resist copulatory attempts, but eventually will submit, and the pair may roll and spin in the water, with the male positioned dorsal to the female during copulation (Kenyon, 1969). Immature males sometimes mimic this pre-copulatory behavior while playing with each other, including facial biting, spinning nose to nose, and mounting each other from behind (M. Staedler, unpub. data, 2000-2010).

Facial biting by the male commonly results in the development of skin and soft tissue lacerations of the female’s nose and face that can occasionally be fatal (Foott, 1970; Staedler & Riedman, 1993). Trauma associated with mating was a primary or contributing cause of death for 11% of fresh dead southern sea otters examined between 2000 and 2003 (Kreuder et al., 2003). In one prior report on breeding-associated mortality, a tagged territorial male sea otter held a struggling female underwater until her body became limp and then copulated repeatedly with her carcass (Staedler & Riedman, 1993). Ten months later, this same male was observed with the carcass of another female sea otter. In both cases, the male was swimming, diving, guarding, and copulating with the carcass.  In other marine mammal species, females and juveniles of both sexes are sometimes injured or killed during mating attempts by male conspecifics (Campagna et al., 1988; Le Boeuf & Mesnick, 1991; Rose et al., 1991; Staedler & Riedman, 1993; Atkinson et al., 1994; Kiyota & Okamura, 2005).  A male-biased adult sex ratio might increase the probability of these aggressive and sometimes fatal interactions (Le Boeuf & Mesnick, 1991).  Mobbing, in which a group of males attempts to mount a single adult female or an immature seal of either sex, has been documented for Hawaiian monk seals (Monachus schauinslandi) (Johanos & Kam, 1986; Atkinson et al., 1994; Johanos et al., 1994). Associated with severe, sometimes fatal skin and soft tissue lacerations to the dorsal integument (Johanos et al., 1994), mobbing has most often been observed in monk seal populations that have a greater ratio of subadult and adult males compared to breeding-age females (Hiruki et al., 1993).

In the polygynous mating systems of sea otters and many pinnipeds, males typically establish a dominance hierarchy based on age, size, and relative fitness such that subdominant males will have limited access to receptive females of the same species (Le Boeuf, 1972, 1974). Where species overlap geographically, interspecific sexual interactions could be the result of a subdominant male seeking a female surrogate. Male southern sea otters become sexually mature at approximately 5 y of age, although often they are unable to successfully defend territories for several more years (Riedman & Estes, 1990). Sexually mature male sea otters may establish and defend aquatic territories in kelp-dominated regions with high female density from which they exclude all other males except dependent pups and recently weaned immature sea otters. Subadult and adult males that are unable to establish territories are usually segregated from reproductive females and territorial males, aggregating with other nonterritorial males in “male areas” that occur at several locations throughout the range, often in sand-bottom habitats like Monterey Bay (Jameson, 1989; Riedman & Estes, 1990). Many nonterritorial male sea otters frequently move long distances between male areas and travel in winter toward the range peripheries where food resources might be more abundant (Jameson, 1989; Tinker et al., 2008).  During the 5 to 10 y leading up to this study, increases in age-specific mortality have disproportionately affected females, with the result that the sex ratio has become skewed toward males (Tinker et al., 2006). An increasingly male-biased sex ratio might have elevated the likelihood of intragender conflicts, including aggressive, forced matings that could result in significant morbidity and mortality. This gender shift in the sea otter population may have triggered the increased aggregation of transient, nonterritorial males in the Monterey Bay region throughout the study period, particularly around Moss Landing. The majority of observed forced copulatory events occurred in Elkhorn Slough in Moss Landing, a region characterized by both a major harbor seal rookery and a large population of nonterritorial male sea otters.  Both tagged males that engaged in sexual behavior with harbor seals in the present study appeared to be nonterritorial transients based on direct observation of behavior over prolonged periods. These subdominant sea otters would have been denied access to female conspecifics by territorial males and may have simply redirected normal sexual responses toward sympatric phocids.  In the current study, strong links were established between observed interspecific copulatory behavior displayed by male sea otters toward harbor seals and specific lesions found during necropsy of the affected harbor seals. The distribution of superficial wounds in harbor seals preferentially over the nose, eyes, and sides of the face and neck is consistent with typical sea otter mating behavior and correlates with notes from direct observation of these interactions. Based on prior reports (Wilson, 1975; Best et al., 1981; Miller et al., 1996; Mortenson & Follis, 1997; Hayward, 2003), pinniped-initiated mating trauma typically has a more dorsal wound distribution because males grasp females from behind with their front flippers; bite them on the dorsal surface of the head, neck, and body to position them; and use the weight of their bodies on land to restrain females to facilitate copulation (Cline et al., 1971; Le Boeuf, 1972; Allen, 1985; Rose et al., 1991).

Limited postmortem examinations of victims of forced copulatory behavior between pinniped species revealed bleeding skin and soft tissue lacerations and hemorrhage on the dorsal aspect of the head and nape (Miller et al., 1996; Mortenson & Follis, 1997), skull fractures with subcutaneous hemorrhage and ocular proptosis (Miller et al., 1996), chest compression or collapse (Best et al., 1981; Miller et al., 1996), and bruising of the distal vagina (Miller et al., 1996), including one female whose intestines were forced out through the anus as a result of crush injury (Best et al., 1981). Ocular trauma, noted in six harbor seals, is an uncommon mating-associated lesion in female sea otters, presumably because sea otter eyes are much smaller and protrude less from the orbit than those of harbor seals. For affected harbor seals, vision loss due to ocular trauma might have restricted their ability to forage and to evade further attacks by male sea otters.  Nine animals examined in depth exhibited vaginal and/or colorectal perforation, which provides strong presumptive evidence for forced copulation.  Although spermatozoa were not observed in the rectum/colon or vaginal tract on cytology or histopathology, the ejaculate could have been forced into the abdominal cavity or diluted by seawater or body fluids; the males might not have ejaculated; or they might not have been producing spermatozoa. All of these factors could be an effect of immaturity, advanced age, or incomplete species-specific copulatory behavior. In both harbor seals and sea otters, vaginal perforations and avulsions were invariably located at the junction of the vagina with the cervix as would be predicted with traumatic perforation due to forced penetration, particularly for immature harbor seals with small reproductive tracts. In contrast, perforations of the more fragile, thinnerwalled gastrointestinal tract were often multiple and were spaced at variable sites along the distal colon and rectum. The average length for an adult male sea otter os penis is 15 cm (Kenyon, 1969), which correlates well with the depths of the perforations. As demonstrated by HS 14, penetration of the penis through the intestinal wall can result in severe bleeding and leakage of feces into the pelvic cavity and abdomen, leading to septic peritonitis.

One surprising lesion that was observed only in female harbor seals and sea otters was the development of acute, severe pneumoperitoneum in animals with vaginal and/or gastrointestinal perforations. Forced copulation resulted in the passage of air from the vaginal lumen or rectum into the abdomen. These perforations appear to have functioned as one-way valves in some cases, allowing air that was forced in during and after copulation to become trapped in the peritoneum under high pressure. This resulted in a severely distended, tympanic abdominal wall and marked cranial displacement of the diaphragm, leading to tension pneumoperitoneum and increased intraabdominal pressure. The end result was restricted diaphragmatic movement, compression of the thoracic cavity, and severe pulmonary atelectasis. In addition, secondary compression of the vena cava, as seen in SO 2, can also limit venous return, resulting in hypotension, hypoxia, and, in severe cases, acute respiratory distress and circulatory collapse (Kim et al., 2000). In all three cases, the diaphragm was displaced so far cranially and the thoracic cavity so tightly compressed by highpressure air in the abdomen, it was deemed to be acutely life threatening. As observed for SO 1 while alive, free peritoneal air can also significantly increase buoyancy and negatively impact an animal’s ability to dive and forage.

All three animals with pneumoperitoneum exhibited perforation or avulsion of the vaginal tract. One sea otter with pneumoperitoneum had perforations of both the vagina and distal colon, but none of the harbor seals with only colorectal perforations exhibited pneumoperitoneum, indicating that development of tension pneumoperitoneum was more closely associated with vaginal perforation in these animals. However, gastrointestinal perforation cannot be excluded as a potential cause of pneumoperitoneum. In humans, pneumoperitoneum has been reported secondary to colorectal perforation during colonoscopy (Marwan et al., 2007) and introduction of compressed air into the rectum (Kim et al., 2000) but has not been reported in association with anal intercourse.  Interestingly, postcoital pneumoperitoneum also has been reported in humans after vigorous sexual intercourse, both secondary to vaginal perforation (Lal et al., 2001; Manchanda & Refaie, 2005) and with an intact vaginal wall (Angel et al., 1988; Johnson et al., 2002). Patients have presented with abdominal distention, abdominal tenderness, vomiting, shoulder pain, dyspnea, and pain on inspiration. In all cases, radiographs revealed free intraperitoneal gas beneath the diaphragm. During sexual intercourse, the penis functioned like a piston, creating a closed system that forced air through a vaginal tear into the peritoneum (Lal et al., 2001; Manchanda & Refaie, 2005); or through the cervix, into the uterus, and out through the fallopian tubes (Angel et al., 1988; Johnson et al., 2002). In humans, this latter event might occur as a result of penile-vaginal disproportion (Manchanda & Refaie, 2005), or for patients in the recent postpartum period (4 to 9 wks postpartum), the cervix could be sufficiently dilated to facilitate passage of air into the uterus during coitus (Angel et al., 1988; Johnson et al., 2002). This could have been a contributing factor for both SO 1 (10 wks postpartum) and SO 2 (dilated cervical os and full-term fetus in the pelvic canal at the time of forced copulation).


Depression & complexity: Beyond the topics (low energy & sleep issues), people experience different symptoms, with different levels of severity, at different times in their lives, with episodes that last different lengths of time

Depression is complicated – this is how our understanding of the condition has evolved over time. Saloni Dattani. Our World In Data, August 19, 2021 https://ourworldindata.org/what-is-depression


Depression is the most common mental health condition in the world, so understanding it has major consequences for a large number of people. But our recognition of the condition was murky until recently. The intricacies of the condition are becoming clearer because of the development of wider surveys, granular scales and more rigorous analysis. We have a better idea of what people experience and how their condition progresses over time.

What we know now is that depression is surprisingly complicated. Low energy and sleeping problems are the most common symptoms. But people with depression experience different symptoms, with different levels of severity, at different times in their lives, with episodes that last different lengths of time. In this post, we’ll explore how researchers have surveyed depression in the general population and how they have developed tools to measure depression. Then we’ll look at what we know about depression today.

Let’s look at each of these factors in more detail before we explore how they have informed our understanding of depression.

→ Surveying depression in the general population

→ Measuring depression on levels

→ Analyzing depression with more rigour

→ Sleeping problems and low energy tend to be the most common symptoms of depression

→ People experience different combinations of symptoms

→ Depression is an umbrella condition which contains subtypes

→ The symptoms of depression tend to change over time

→ Episodes of depression can occur frequently

→ Episodes of depression can last a long time

→ Depression is complicated

Moral universalism (the extent to which people exhibit the same level of altruism and trust toward strangers as toward in-group members): Have fewer friends, spend less time with them, and feel more lonely

Moral Universalism: Measurement and Economic Relevance. Benjamin Enke, Ricardo Rodríguez-Padilla, Florian Zimmermann. Management Science, Aug 10 2021. https://doi.org/10.1287/mnsc.2021.4086

Abstract: Many applied economic settings involve trade-offs between in-group members and strangers. To better understand decision making in these contexts, this paper measures and investigates the economic relevance of heterogeneity in moral universalism: the extent to which people exhibit the same level of altruism and trust toward strangers as toward in-group members. We first introduce a new experimentally validated, survey-based measure of moral universalism that is simple and easily scalable. We then deploy this tool in a large, representative sample of the U.S. population to study heterogeneity and economic relevance. We find that universalism is a relatively stable trait at the individual level. In exploratory analyses, heterogeneity in universalism is significantly related to observables: Older people, men, the rich, the rural, and the religious exhibit less universalist preferences and beliefs. Linking variation in universalism to self-reports of economic and social behaviors, we document the following correlations. Universalists donate less money locally, but more globally, and are less likely to exhibit home bias in equity and educational investments. In terms of social networks, universalists have fewer friends, spend less time with them, and feel more lonely. These results provide a blueprint for measuring moral universalism in applied settings and suggest that variation in universalism is relevant for understanding a myriad of economic behaviors.

Why are heavily regulated European labor markets associated with a smaller share of women in top management positions compared with liberal market economies such as in the US?

The Dilemma of Gender Equality: How Labor Market Regulation Divides Women by Class. Torben Iversen, Frances McCall Rosenbluth, Øyvind Skorge. Daedalus (2020) 149 (1): 86–99. https://doi.org/10.1162/daed_a_01775

Abstract: Women shoulder a heavier burden of family work than men in modern society, preventing them from matching male success in the external labor market. Limiting working hours is a plausible way to level the playing field by creating the possibility of less gendered roles for both sexes. But why then are heavily regulated European labor markets associated with a smaller share of women in top management positions compared with liberal market economies such as in the United States? We explain this puzzle with reference to the difficulty of ambitious women to signal their commitment to high-powered careers in regulated markets.

Despite a large influx of women into mainly service sector jobs over the past four decades, women continue to be underrepresented in the labor market, and they earn less on average than men. These gender differences are almost certainly linked to greater de facto responsibilities of women in child-rearing and household work, but there are major and intriguing differences across rich democracies.

In low- and mid-level jobs, the differences are fairly well understood. In Europe, union bargaining and wage compression put a higher floor under the lowest paid jobs where women disproportionately find themselves in every country. The gender gap in wages is smaller in Europe as a result, although another reason could be that low-productivity jobs may be scarcer. Regulated working hours, compatible with work-family balance, complements family-friendly policies such as public subsidization of childcare. Yet if this broadly accepted story is accurate, we should also expect the number of female managers of large firms and university-educated professionals to be rising as we travel from the United States and the United Kingdom to continental Europe and further north to Scandinavia. In fact, the reverse is true. Although the number is small everywhere, the share of women in high-powered private sector careers in the United States significantly exceeds that in Germany or Denmark. The explanation cannot be the long hours and inflexible schedules of professional work, since this is equally true in the United States. Also of no help are theories of occupational performance that predict greater female success in jobs requiring relationship management and multitasking, since these criteria characterize managerial jobs across the United States and Europe.

Our explanation instead focuses on unintended consequences: regulations that curtail working hours at nonmanagerial levels discourage employers from promoting women to higher levels, given that they have incomplete information about candidates. To employers who can measure productivity only imperfectly, long working hours are a signal – though a noisy one – of expected productivity and therefore of suitability for many kinds of higher-level managerial jobs. Labor market regulations tend to equalize both wages and employment opportunities for men and women when productivity is linked to hours worked, but it has the perverse effect of intensifying statistical discrimination against women in highend jobs, even when these jobs are themselves unregulated. This logic explains the opposite effects of working-hours regulation at the low and high ends of the occupational hierarchy. Sadly, all good things do not go together, and labor market regulations produce good and bad results at the same time.

We begin by distinguishing jobs along three dimensions: 1) whether hours worked are positively associated with (hourly) productivity; 2) whether there are ample opportunities for promotions based on competition rather than seniority; and 3) whether working hours are regulated (restricted) below the management level.

As a general matter, low- and mid-level jobs may or may not be regulated in terms of working hours and wages, whereas top-end jobs are typically unregulated. While both women and men may have equal levels of ambition, family responsibilities are borne disproportionately by women in a way that reduces, on average, their availability to work around the clock (see Figure 1).