Respectable conviviality: Orthodox Christianity as a solution to value conflicts in southern Ethiopia

This article explains the recent emergence of Orthodox Christianity in a majoritarian Evangelical Protestant community in southern Ethiopia. Examining conversion motives and forms of religious engagement, I show that Orthodoxy is attractive to erstwhile followers of traditional practice because it affords them the solution to a value conflict. Joining an institutionalized ‘religion’ associated with national elites, converts attain the respectability formerly denied them by Evangelicals. And since Orthodoxy is less puritan than local Evangelicalism, conversion does not come at the expense of conviviality. An ethnographic discussion of this process of value harmonization provides the basis for a conceptual contribution to anthropological value theory, while also offering new insights for the debate about different modalities of Christian change.     

Depression and suicidality as evolved credible signals of need in social conflicts

Mental health professionals generally view major depression and suicidality as pathological responses to stress that elicit aversive responses from others. An alternative hypothesis grounded in evolutionary theory contends that depression and suicidality are honest signals of need in response to adversity that can increase support from reluctant others when there are conflicts of interest. To test this hypothesis, we examined responses to emotional signals in a preregistered experimental vignette study involving claims of substantial need in the presence of conflicts of interest and private information about the signaler's true level of need. In a sample of 1240 participants recruited from Amazon Mechanical Turk, costlier signals like depression and suicidality increased perceptions of need, reduced perceptions of manipulativeness, and increased likelihood of support compared to simple verbal requests and crying without further symptoms. The effect of signaling on likelihood of support was largely mediated by the effect of signaling on participants' belief that the signaler was genuinely in need. Our results support the hypothesis that depression and suicidality, apparent human universals, are credible signals of need that elicit more support than verbal requests, sad expressions, and crying when there are conflicts of interest.     

Parental investment related to social systems in microtines

Summary Laboratory offspring of wild-caught voles Clethrionomys glareolus and Microtus agrestis, bred for 1 year under constant conditions, were examined with regard to sex ratios and weights at weaning and at 2 months of age. C. glareolus exhibits female territoriality and M. agrestis male territoriality in summer. The adults die away in late summer-autumn. Early-summer young mature in the year of birth but late-summer young do not reach maturity until the following year. C. glareolus young showed a male bias in early summer and a female bias in late summer. Conditions were the opposite but less clear in M. agrestis. C. glareolus males grew comparatively faster than M. agrestis males and showed a markedly higher early summer male: female weight ratio at 2 months of age. Maternal investment thus appears clearly related to the social system; the sex with the largest number and highest quality of young was that which was not limited in number by territoriality. However, the investment depended also on the time until maturation of the young.     

Trophallaxis and reproductive conflicts in social bees

In the eusocial Hymenoptera, reproductive division of labour is a key aspect of colony organisation. In most of its species, workers are sterile and are unable to reproduce, while the queen monopolises reproduction. When workers are able to reproduce, a conflict with the queen or with other workers over male production is predicted. Because this reproduction may involve costs for the colony, the potential conflict over male parentage gives rise to important questions, such as what are the proximate mechanisms that allow a queen to control the reproductive potential of its workers, and which factors make some workers fertile and others not. In the groups where it occurs, an important mechanism for the regulation of reproduction is trophallaxis (the process of mutual feeding through regurgitation that occurs in several species of social insects). Trophallaxis gives dominant individuals a trophic advantage by taking nutrients from submissive individuals. In advanced eusocial species of bees, trophallaxis may also serve as an alternative hierarchical interaction in the absence of agonistic conflicts. In this way, trophallaxis not only represents an alternative path for hierarchical interactions, but it may be evolutionary linked to intracolonial conflict among workers.     

Strength of social tie predicts cooperative investment in a human social network

Social networks--diagrams which reflect the social structure of animal groups--are increasingly viewed as useful tools in behavioural ecology and evolutionary biology. Network structure may be especially relevant to the study of cooperation, because the action of mechanisms which affect the cost:benefit ratio of cooperating (e.g. reciprocity, punishment, image scoring) is likely to be mediated by the relative position of actor and recipient in the network. Social proximity could thus affect cooperation in a similar manner to biological relatedness. To test this hypothesis, we recruited members of a real-world social group and used a questionnaire to reveal their network. Participants were asked to endure physical discomfort in order to earn money for themselves and other group members, allowing us to explore relationships between willingness to suffer a cost on another's behalf and the relative social position of donor and recipient. Cost endured was positively correlated with the strength of the social tie between donor and recipient. Further, donors suffered greater costs when a relationship was reciprocated. Interestingly, participants regularly suffered greater discomfort for very close peers than for themselves. Our results provide new insight into the effect of social structure on the direct benefits of cooperation.     

Operant cycles and imitational learning in a social setting

The provisioning of a communally-maintained group of rhesus monkeys with operant procedures reveals the following: (1) the temporal interaction of the daily work cycles for several discrete reinforcers; (2) the interaction of these cycles with other patterns of social activity; (3) the independent acquisition of operant schedules by animals recently born to the group and of new schedules by all members of the group.     

Seasonal extension of the soldier instar as a route to increased defence investment in the social aphid Pemphigus spyrothecae

Abstract.  1. The possibility that the duration of the soldier instar could be extended over the course of the galling season was examined in Pemphigus spyrothecae Passerini (Hemiptera: Aphididae). In this species, the individuals of one morph of the dimorphic first instar are non-sterile specialised defenders known as soldiers.
2. In the face of a declining birth rate, the proportion of first-instar soldiers to first-instar non-soldiers was found to increase. This provides strong evidence of extension of the soldier instar over time.
3. Instar extension provides a mechanism for post-natal investment in soldiers and allows individuals with insufficient time to mature to remain in the defensive stage so that they may continue to make an indirect contribution to their clone's reproductive success.     

Within-colony relatedness asymmetry and social conflicts in ants

The haplodiplo?d sex-determining system of Hymenoptera, whereby males usually develop from unfertilized eggs and females from fertilised eggs, results in relatedness coefficients that are not uniform among colony members. These asymmetries in relatedness are directly affected by the genetic architecture of the colony, which in turn depends on various factors such as queen number or queen mating frequency. Relatedness asymmetries induce different fitness returns per unit investment and, as a result, conflicts over brood composition may arise among colony members. Conflicts between the queen(s) and the workers over sex ratio represent one of the most frequent conflicts in eusocial Hymenoptera. Arrhenotoky allows queens great flexibility to control the sex of their progeny, by fertilizing or not the eggs; however because workers take care of the brood, they may influence the sex ratio by preferentially rearing one sex. Another salient conflict concerns the females over reproduction. In species where workers can mate and reproduce, physical aggressions or chemical communication may lead to dominance hierarchies for access to reproduction.     

Sex determination: ways to evolve a hermaphrodite

Most species of the nematode genus Caenorhabditis reproduce through males and females; C. elegans and C. briggsae, however, produce self-fertile hermaphrodites instead of females. These transitions to hermaphroditism evolved convergently through distinct modifications of germline sex determination mechanisms.     

Sperm competition within a dominance hierarchy: investment in social status vs. investment in ejaculates

There is increasing recognition that male-male competition can take many forms, but as yet the form is not predictable a priori. Many recent studies have focused attention on how males in disadvantaged mating roles compensate through sperm competition. However, mating systems in which subordinate males are reproductively suppressed, particularly through the stress of social interactions, may limit the ability of males to respond by increasing investment in sperm quality. We examined the interaction between social status and ejaculate tactics in Nauphoeta cinerea, a cockroach that has a mating system with well-characterized dominance hierarchies. Both social experience with other males and social status influenced aspects of ejaculates. The stress of social interactions reduced the size of the ejaculate and number of sperm inseminated. In ejaculates formed prior to social experience, however, males that go on to become dominant inseminated more sperm than males that go on to become subordinate, suggesting innate differences among males. Our results show that though selection for increased success in sperm competition for subordinate males in a hierarchy can occur, both the traits and the way in which the balance between pre- and post-copulatory strategies is negotiated will depend on specific details of the mating system. These details will include how the physiological effects of social interactions may limit selection through male-male competition.     

Ovarian indexes as indicators of reproductive investment and egg-laying activity in social insects: a comparison among methods

High reproductive skew among colony members is a fundamental feature of insect’s societies, where one or few individuals monopolize reproductive output. However, many social insect species retain a high reproductive plasticity, with all colony members able of developing ovaries and laying eggs. Understanding the partition of reproduction inside these plastic societies is a key step in the comprehension of social evolution. The reproductive status of social insects is usually evaluated by looking at the degree of ovarian development, and a great variety of different methods has been used even in the same species. It is not known, however, to which extent the different methods give comparable results and represent good indexes of individual egg-laying activity. We used the model paper wasp species Polistes dominula to tackle these issues, by compiling the main methods of ovarian development assessment on the same set of individuals and quantifying their egg-laying activity. Our results showed that all examined methods give similar and highly correlated results, but none of them allows reliable estimates of the egg-laying activity. Ovarian indexes (whatever method is used) are good indicators of individual reproductive potential, but can only roughly reflect actual reproductive activity. We thus propose to be very cautious in extrapolating egg-laying activity levels from ovarian index estimations.     

When will a sexual population evolve to an ESS?

A diploid, Mendelian population is considered in which m alleles at a single autosomal locus uniquely determine the phenotype of each individual. In the population, a game-theoretical conflict is supposed. If the genetic system is able to uniquely realize the phenotypic evolutionarily stable strategy (ESS) state then the sexual population will evolve to this ESS.     

Body-size evolution: how to evolve a mammoth moth.

Separate recent studies have revealed the physiological changes underlying the evolution of body size in an insect and advanced our understanding of the genetics of insect growth. These studies highlight the gulf between physiological and genetic studies of growth control and the exciting opportunities for unification of these fields.     

Cues of parental investment as a factor in attractiveness

One prediction derived from parental investment theory is that women will be more attentive than men are to cues of a prospective mate's dispositions to invest in children. Research with 1793 Internet participants, representing a diverse population sample, found that (a) women tend to be generally more critical than men are in their evaluations of potential mates, but not potential friends or neighbors, and (b) cues of a positive disposition towards parental investment (DPI) have a positive influence on female evaluations of the attractiveness of males. This latter effect, however, is less domain-specific than previous research [La Cerra, M. M. (1995). Evolved mate preferences in women: Psychological adaptations for assessing a man's willingness to invest in offspring (doctoral dissertation, University of California, Santa Barbara). Dissertation Abstracts International: Section B: the Sciences & Engineering Mar, 55(9-B), 4149] indicated; it is not limited to mating contexts and to cues focusing on parental investment. In fact, much of the sex difference appears to be due to indifference by males towards cues of female DPI. A second study further clarified that the previous findings were not due solely to the Internet methodology or the immediate accessibility of images being evaluated.     

Salamander morph frequencies do not evolve as predicted in response to 40 years of climate change

The global climate is changing rapidly, yet biotic responses remain uncertain. Most studies focus on changes in species ranges or plastic responses like phenology, but adaptive evolution could be equally important. Studying evolutionary responses is challenging given limited historical data and a poor understanding of genetically variable traits under selection. We take advantage of a historical dataset to test for an adaptive response to climate change in a widespread, polymorphic amphibian, the eastern red‐backed salamander Plethodon cinereus. We resurveyed color morph frequencies across New England to test for an adaptive shift in response to climate change. We modeled historical and present‐day morph proportions as a function of climate and tested the accuracy of predictions both within and across different time periods. Our models showed moderate accuracy when predicting morph frequencies within time periods, but poor accuracy across time periods. Despite substantial changes in climate and significant relationships between morph frequency and climate variables within periods, we found no evidence for the predicted shift in morph frequencies across New England. The relationship between climate and color morph frequencies is likely more complex than originally suggested, potentially involving the interplay of additional factors such as microclimate variation, land use changes, and frequency‐dependent selection. Model extrapolation and changes in the correlation structure of climate variables also likely contributed to poor predictive ability. Evolution could provide a means to moderate the effects of climate change on many species. However, we often do not understand the direct links between climate variation, traits, and fitness. Therefore, forecasting climate‐mediated evolution remains an ongoing and important challenge for understanding climate change threats to species.