Sex in an Evolutionary Perspective: Just Another Reaction Norm

It is common to refer to all sorts of clear-cut differences between the sexes as something that is biologically almost inevitable. Although this does not reflect the status of evolutionary theory on sex determination and sexual dimorphism, it is probably a common view among evolutionary biologists as well, because of the impact of sexual selection theory. To get away from thinking about biological sex and traits associated with a particular sex as something static, it should be recognized that in an evolutionary perspective sex can be viewed as a reaction norm, with sex attributes being phenotypically plastic. Sex determination itself is fundamentally plastic, even when it is termed “genetic”. The phenotypic expression of traits that are statistically associated with a particular sex always has a plastic component. This plasticity allows for much more variation in the expression of traits according to sex and more overlap between the sexes than is typically acknowledged. Here we review the variation and frequency of evolutionary changes in sex, sex determination and sex roles and conclude that sex in an evolutionary time-frame is extremely variable. We draw on recent findings in sex determination mechanisms, empirical findings of morphology and behaviour as well as genetic and developmental models to explore the concept of sex as a reaction norm. From this point of view, sexual differences are not expected to generally fall into neat, discrete, pre-determined classes. It is important to acknowledge this variability in order to increase objectivity in evolutionary research.     

Factors Associated with Inconsistent Condom Use among Men Who Have Sex with Men in Cambodia

Background

Compared to the general population, men who have sex with men (MSM) are at greater risk for HIV and less understood due to their more hidden and stigmatized nature. Moreover, the discrepancy in findings in the literature merits further investigations in MSM populations from different cultures and settings. We therefore conducted this study to explore factors associated with inconsistent condom use among high-risk MSM in Cambodia.

Methods

This cross-sectional study was conducted in 2014 among 367 MSM randomly selected from Battembang and Siem Reap using a two-stage cluster sampling method. A structured questionnaire was used for face-to-face interviews to collect information on characteristics of respondents, HIV testing history, self-perception of HIV risk, substance use, sexual behaviors, mental disorders, and HIV knowledge. Multivariable logistic regression analysis was performed to identify factors independently associated with inconsistent condom use.

Results

On average, 62.3% of respondents reported that they always used condoms over the past three months. The rates varied with types of sexual partners; the proportion of respondents who reported always using condoms was 55.1%, 64.2%, 75.9%, 73.0%, 78.1%, and 70.3%, for sexual partners who were girlfriends, boyfriends, female sex workers, male sex workers, female clients, or male clients, respectively. After adjustment, inconsistent condom use was significantly associated with age of ≥25 (AOR = 1.77, 95% CI = 1.09–2.86), self-rated quality of life as good or very good (AOR = 4.37, 95% CI = 1.79–5.67), self-perception of higher HIV risk compared to the general population (AOR = 2.37, 95% CI = 1.35–4.17), illicit drug use in the past three months (AOR = 5.76, 95% CI = 1.65–10.09), and reported consistent lubricant use when selling anal sex to men in the past three months (AOR = 2.85, 95% CI = 1.07–8.12).

Conclusions

We found risky sexual behaviors to be considerably high among MSM in this study, especially among those who used illicit drugs or were older than 25. HIV education and social marketing should be expanded and specifically designed for MSM to better educate on the increased risk of HIV with unprotected anal sex and illicit drug use as risk factors, and the importance of the use of both condoms and lubricant during anal intercourse.     

Pet Ownership in Childhood and Socio-Emotional Characteristics,Work Values and Professional Choices in Early Adulthood

ABSTRACT

The main goal of this study, partly retrospective in character, was to explore if and how pet ownership in childhood is related to several indicators of socio-emotional development, as well as work values and professional choices in early adulthood. The sample consisted of 356 students (200 females, 156 males) from different colleges of the University of Zagreb, representing helping (n=200) and non-helping (n=156) professions. The mean age of the students was 21 years. Seventy-four percent of the participants had had a pet during childhood, mostly dogs. Participants who had owned a pet during childhood reported quite a strong attachment to it. In addition, pets were rated lower than family members and friends, but higher than television, relatives and neighbors in terms of the social support derived from them during childhood. Discriminant analysis was performed in order to examine whether young adults – those who had owned a pet during childhood and those who hadn't – differed in emotional and motivational characteristics, and whether there was a correlation with their chosen subject of study. Pet ownership in childhood was a grouping variable, while measures of current socio-emotional functioning (empathy, prosocial behavior, social anxiety and loneliness), value orientations (self-actualisation, individualistic, social, utilitarian and adventurous) and chosen subject of study (helping or non-helping profession) were predictors. A significant discriminant function was obtained. Correlations between discriminating variables and discriminant function showed that young adults who had had a pet during childhood were more empathetic, more prone to choose helping professions, and more oriented towards social values than those who did not have a pet during childhood.     

Surviving Shattered Worlds: Vietnam and Cambodia

Shattered World: Adaptation and Survival among Vietnam's Highland People during the Vietnam War . Gerald Cannon Hickey
Beyond the Killing Fields: Voices of Nine Cambodian Survivors in America . Usha Welaratna     

Modelling Discrete Choice Variables in Assessment of Teaching Staff Work Satisfaction

Levels of self-reported job satisfaction and motivation were measured by survey in a sample of 286 teachers. Using the discrete choice framework, the paper tries to assess the relevance of the considered indicators (demographic, social, motivational) in overall teaching work satisfaction. The findings provide evidence that job satisfaction is correlated significantly with level of university degree held by the teacher, type of secondary school where the teacher is enrolled, revenues, and salary-tasks adequacy. This is important for the Romanian economy, since the education system is expected to provide future human resources with enhanced skills and abilities.     

Maternal Condition and Nest Site Choice: An Alternative for the Maintenance of Environmental Sex Determination?

SYNOPSIS. Egg size and nest site selection are two potentialeffects that can have a persistent influence on the phenotypeof offspring. In this paper, I develop the maternal condition-dependentchoice hypothesis for the maintenance of environmental sex determination.The hypothesis stipulates three conditions: 1) there must bevariation in the maternal effect, 2) the variation in the maternaleffect must influence fitness of the offspring differently betweenthe sexes, and 3) female reproductive behavior is determinedby her condition or how her condition will influence her offspring'sfitness. Females with the ability to recognize environmentsthat have a higher probability of producing the sex that wouldbenefit the most from maternal condition will have an advantage.Using egg size as a maternal effect, I test this hypothesisin the diamondback terrapin, an emydid turtle with temperature-dependentsex determination. Terrapins have large variation in egg sizeamong clutches and little variation within clutches. Egg massis the primary determinant of hatchling mass and can resultin as much as a three year difference in reaching minimum sizeof first reproduction in females, but may not affect age orsize of first reproduction in males. Finally, terrapins selectopen nesting sites with warmer incubation conditions and placelarger eggs there. Females place smaller eggs in cooler sites.Terrapin reproduction is consistent with the prediction of thematernal condition-dependent nest site choice hypothesis. Themodel and supporting data demonstrate how maternal effects canbe an important factor to consider in studies of environmentalsex determination.     

Fitness in the universe: Choices and necessities

We live in a universe of chance, but not of accident. Repeatedly in the course of its development choices have been made for which one can ask the reasons. One such choice is fundamental: if the proton had not so much greater mass than the electron, all matter would be fluid; and if the proton did not have exactly the same numerical charge as the electron — or some simple multiple of that charge — virtually all matter would be charged. If a universe were started with charged hydrogen, it could expand, but probably nothing more. Hydrogen, carbon, nitrogen and oxygen play as fundamental — and irreplaceable — roles in the metabolism of stars as of living organisms. Both metabolisms are coupled, through radiation from the stars providing the energy on which life must come ultimately to run on the planets. In the course of their evolution on the Earth, living organisms have found their way repeatedly and exclusively to certain types of organic molecule to perform specific functions; so, for example, the chlorophylls for photosynthesis, and carotenoids for plant phototropism and for vision. It is argued that some measure of necessity has governed these choices; and that an extended principle of natural selection has operated at all levels of material organization to produce such elements of order and compatibility in the universe.     

Drug Use and Sex Work: Competing Risk Factors for Newly Acquired HIV in Yunnan,China

Objective

To investigate the HIV incidence and its related factors among female sex workers (FSWs) in a high prevalence area where injection drug use is also widely documented.

Method

A cross-sectional study of 1642 female sex workers (FSWs) was conducted in Honghe Prefecture of Yunnan Province. Interviewed-questionnaires were administrated to collect information on sexual partnerships, condom use and illicit drug using behaviors etc. Blood samples were collected to test for HIV antibodies, and all HIV seropositive specimens were tested with the BED IgG capture-based enzyme immunosorbent assay (BED-CEIA) to distinguish between new and established HIV infection (<153 days).

Results

15.9% (261/1642) of participants reported ever having used drugs, and 7.4% had injected in recent 3 months. The overall HIV prevalence was 10.2% (168/1642), among which 16.7% (28/168) were identified as recent infections using BED-CEIA. The crude HIV incidence estimated from BED-CEIA results was 4.4 (95%CI 2.8–6.0) /100 person years (PY). Multivariate logistic analysis showed that an illicit drug using history (by either self-reporting or urine opiates testing) was both significant risk factors both for HIV established and recent infection (each p<0.05). Drug using FSWs (DU-FSW) reported more male clients in the previous week, and had significantly higher prevalence of HIV, chlamydia trachomatis and HSV-2 as compared to non DU-FSW (each p<0.05).

Conclusion

Our results show that a history of drug use poses significant risks for both new and established HIV infection among FSWs, and that HIV-incidence among Honghe FSWs is relatively high compared to similar populations. Comprehensive interventions targeted at DU-FSWs'' injection drug using and high risk sexual behaviors are urgently needed to reduce the rapid spread of HIV epidemic.     

An Investigation on Social Representations: Inanimate Agent Can Mislead Dogs (Canis familiaris) in a Food Choice Task

The nature of mental representation of others plays a crucial role in social interactions. Dogs present an ideal model species for the investigation of such mental representations because they develop social ties with both conspecifics and heterospecifics. Former studies found that dogs’ preference for larger food quantity could be reversed by humans who indicate the smaller quantity. The question is whether this social bias is restricted to human partners. We suggest that after a short positive social experience, an unfamiliar moving inanimate agent (UMO) can also change dogs’ choice between two food quantities. We tested four groups of dogs with different partners: In the (1) Helper UMO and (2) Helper UMO Control groups the partner was an interactive remote control car that helped the dog to obtain an otherwise unreachable food. In the (3) Non-helper UMO and (4) Human partner groups dogs had restricted interaction with the remote control car and the unfamiliar human partners. In the Human partner, Helper UMO and Helper UMO Control groups the partners were able to revert dogs’ choice for the small amount by indicating the small one, but the Non-helper UMO was not. We suggest that dogs are able to generalize their wide range of experiences with humans to another type of agent as well, based on the recognition of similarities in simple behavioural patterns.     

Foraging for Work and Age-Based Polyethism: The Roles of Age and Previous Experience on Task Choice in Ants

In social insects, colonies commonly show temporal polyethism in worker behavior, such that a worker follows a predictable pattern of changes between tasks as it ages. This pattern usually leads from workers first doing a safe task like brood care, to ending their lives doing the most dangerous tasks like foraging. Two mechanisms could potentially underlie this pattern: (1) age‐based task allocation, where the aging process itself predisposes workers to switch to more dangerous tasks; and (2) foraging for work, where ants switch to tasks that need doing from tasks which have too many associated workers. We tested the relative influence of these mechanisms by establishing nests of Camponotus floridanus with predetermined combinations of workers of known age and previous task specialization. The results supported both mechanisms. Nests composed of entirely brood‐tending workers had the oldest workers preferentially switching to foraging. However, in nests initially composed entirely of foragers, the final distribution of tenders and foragers was not different from random task‐switching and therefore supportive of foraging for work. Thus, it appears that in C. floridanus there is directionality to the mechanisms of task allocation. Switching to more dangerous tasks is age‐influenced, but switching to less dangerous tasks is age‐independent. The results also suggest that older workers are more flexible in their task choice behavior. Younger workers are more biased towards choosing within‐nest tasks. Finally, there are effects of previous experience that tend to keep ants in familiar tasks. Task allocation based on several mechanisms may balance between: (1) concentrating the most worn workers into the most dangerous tasks; (2) increasing task performance levels; and (3) maintaining behavioral flexibility to respond to demographic perturbations. The degree to which behavior is flexible may correlate to the frequency of such perturbations in a species.     

Just Anger: Scenarios of Indignation in Botswana and Madagascar

Particular scenarios of anger in two African societies are compared in order to discern some of the complex ways in which emotion is related to cultural context and social practice. The disappointment of Kgalagadi elders (dikgaba) in Botswana and the irascibility and violence of royal Sakalava spirits in Madagascar entail moral inspection with respect to the justifiability of anger and the locus of fault. Through case studies we emphasize the interpersonal and hierarchical dimensions of justifiable anger and suggest a comparison with Western 'guilt.' The circulation of anger between the generations is contrasted to a situation in which the capacity for imagining the indignation of others collapses into indignity.