Human behavioral ecology: current research and future prospects

Human behavioral ecology (HBE) is the study of human behavior from an adaptive perspective. It focuses in particular on how human behavior varies with ecological context. Although HBE is a thriving research area, there has not been a major review published in a journal for over a decade, and much has changed in that time. Here, we describe the main features of HBE as a paradigm and review HBE research published since the millennium. We find that the volume of HBE research is growing rapidly, and its composition is changing in terms of topics, study populations, methodology, and disciplinary affiliations of authors. We identify the major strengths of HBE research as its vitality, clear predictions, empirical fruitfulness, broad scope, conceptual coherence, ecological validity, increasing methodological rigor, and topical innovation. Its weaknesses include a relative isolation from the rest of behavioral ecology and evolutionary biology and a somewhat limited current topic base. As HBE continues to grow, there is a major opportunity for it to serve as a bridge between the natural and social sciences and help unify disparate disciplinary approaches to human behavior. HBE also faces a number of open questions, such as how understanding of proximate mechanisms is to be integrated with behavioral ecologys traditional focus on optimal behavioral strategies, and the causes and extent of maladaptive behavior in humans

The Cultural Evolution of Economic Development

Economic development has several stages, from the exchange of tools and weapons in prehistory, to the adoption of money systems, to globalised economies driven by digitally-represented currencies. These stages present different challenges to societies, but also common ones. Perhaps the most important of these is cooperation. Exchange puts parties in positions vulnerable to exploitation, as they have to give payment in anticipation of goods, or goods in anticipation of payment. At its origin, money use creates a similar situation in which a party gives up valuable objects for a promise of future repayment. Explaining the diversity in economic performance and money systems therefore requires consideration of ecological and cultural factors that shape the levels of cooperation in societies. History can also have an influence on this diversity. Events in a society’s history can have persistent effects on its culture and institutions, and more general patterns of shared history can determine how culturally similar societies are. A cultural evolutionary framework can be used to synthesise these different factors as part of the same explanation. Historical experiences, the ecology and cultural traits all shape variation in each other and create conditions that determine the adaptiveness of cooperation, and therefore the potential for money use and large-scale economic activity to emerge and spread. Using a multiple method and multiple hypothesis approach, in this thesis I seek to examine existing theories for variation in economic development and money use, and generate and test new hypotheses using a cultural evolutionary framework

Genetics and developmental biology of cooperation

Despite essential progress towards understanding the evolution of cooperative behaviour, we still lack detailed knowledge about its underlying molecular mechanisms, genetic basis, evolutionary dynamics and ontogeny. An international workshop "Genetics and Development of Cooperation," organized by the University of Bern (Switzerland), aimed at discussing the current progress in this research field and suggesting avenues for future research. This review uses the major themes of the meeting as a springboard to synthesize the concepts of genetic and nongenetic inheritance of cooperation, and to review a quantitative genetic framework that allows for the inclusion of indirect genetic effects. Furthermore, we argue that including nongenetic inheritance, such as transgenerational epigenetic effects, parental effects, ecological and cultural inheritance, provides a more nuanced view of the evolution of cooperation. We summarize those genes and molecular pathways in a range of species that seem promising candidates for mechanisms underlying cooperative behaviours. Concerning the neurobiological substrate of cooperation, we suggest three cognitive skills necessary for the ability to cooperate: (i) event memory, (ii) synchrony with others and (iii) responsiveness to others. Taking a closer look at the developmental trajectories that lead to the expression of cooperative behaviours, we discuss the dichotomy between early morphological specialization in social insects and more flexible behavioural specialization in cooperatively breeding vertebrates. Finally, we provide recommendations for which biological systems and species may be particularly suitable, which specific traits and parameters should be measured, what type of approaches should be followed, and which methods should be employed in studies of cooperation to better understand how cooperation evolves and manifests in nature

Sociogenomics of maternal care and parent-offspring coadaptation in the European earwigs (Forficula auricularia)

Conflict and cooperation are ubiquitous in nature and in animal families where parents and offspring reciprocally influence each other's behavior and fitness. Evolutionary models predict selection for parent-offspring coadaptation that strike balance between parents pursuing self-fitness versus offspring demanding parental investment. Ultimately, it facilitates well-coordinated parenting and optimized cooperation with their offspring in the face of sexual reproduction and genetic recombination which cause genetic conflict. However, the genomic basis of parent-offspring coadaptation is poorly understood. My dissertation focused on the sociogenomics of materanl care and parent-offspring coadaptation in the European earwig (Forficula auricularia), a facultative uni-parental female care insect. In the first chapter, we sequenced the transcriptome of the European earwig from various tissues and developmental stages of female and male applying Roche 454 pyrosequencing and Illumina HiSeq. The reads were de novo assembled independently and screened for possible microbial contamination and repeated elements. Hybrid assembly of these data yield comprehensive transcriptome with a low level of fragmentation comparing to the eukaryotic core gene dataset. More than 8,800 contigs of the hybrid assembly show significant similarity to insect-specific proteins and those were assigned for Gene Ontology terms. Finally, I validated the transcriptome and established a quantitative PCR method and applied it to homologs of five known sex-biased genes of the honeybee. The qPCR pilot study confirmed sex specific expression and also revealed significant expression differences between the brain and antenna tissue samples. The transcriptome presented here offers new opportunities to study the molecular bases and evolution of parental care and sociality in arthropods. In the second chapter, I identified two parent-offspring coadapted genes, PebIII and Th, in the European earwig, based on comparative transcriptomics from experimentally manipulated mother-offspring interactions. Functional study applying RNAi revealed that PebIII in offspring enhances survival, in mothers enhances their relative investment in future reproduction and indirectly delayed offspring development; Th in mothers enhanced food provisioning, in offspring indirectly enhanced the likelihood of maternal future reproduction. These results suggested PebIII being reciprocally selfish while Th being reciprocally altruistic in both mothers and offspring. Metabolic pathway analyses further indicated the role of Th-restricted dopaminergic reward, PebIII mediated chemical perception and regulations between insulin signaling, juvenile hormone and vitellogenin in parent-offspring coadaptation and social evolution. In the third chapter, I manipulated the interaction between earwig mothers and offspring over two generation and investigated transgenerational effects of maternal care on the expression of the two parent-offspring coadapted genes found in chapter2 and the fitness consequences in mothers and offspring. Significant transgenerational effects were found for the expression of PebIII and Th in the head of mothers. The expression of PebIII in the whole body of offspring showed significant effects of transgeneration treatment, current generation treatment and current generation by transgeneration treatments interaction. Significant transgenerational effect was found for relative maternal investment in future reproduction and offspring growth rate. Maternal future reproduction and latency for maternal future reproduction showed significant effects of current generation parental care treatment. Our results indicates an epigenetic regulation of gene expressions underlying parent-offspring coadaptation. In the last chapter, the expressions of parent-offspring coadapted genes were validated using Fluidigm gene expression dynamic array. An additional treatment was included to control for time effect. We found the regulation of Th and PebIII were not influenced by the interaction between parent and offpsirng per se, but rather controlled by the reproductive stage of mothers suggesting preprogrammed expression in earwig. Such regulation of parenting genes in the sub-social species might be ancestral to the age-dependent division of labor in eusocial system. These four chapters of my thesis were a series of continuous work and provided significant insights into the genomic basis of parent-offspring coadaptation. I established qPCR method to validate the de novo hybrid assembled transcriptome of the European earwig. I identified candidate parent-offspring coadapted genes using comparative trascriptomics. I established the method of Fluidigm gene expression dynamic array for earwigs to validate the RNA-Seq results. I established the RNAi techonology for earwigs to manipulate gene expressions and to study the social function of candidate genes. I demonstrated that PebIII and Th are two parent-offspring coadapted genes, which are co-regulated in mothers and offspring during active post-hatching parental care. Their expression were preprogrammed in mothers, reflecting the reproductive stage of females. Both genes showed causal effects on the behavior and fitness of earwig mothers and nymphs, coordinating the selfishness and altruism in family life. I showed transgenerational effects of maternal care on the expression of PebIII and Th, and opened the door for future studies of the epigenetic mechanisms regulating gene expression over generations and maintaining parent-offspring coadaptation in earwigs

The role of visual adaptation in cichlid fish speciation

D. Shane Wright (1) , Ole Seehausen (2), Ton G.G. Groothuis (1), Martine E. Maan (1) (1) University of Groningen; GELIFES; EGDB(2) Department of Fish Ecology & Evolution, EAWAG Centre for Ecology, Evolution and Biogeochemistry, Kastanienbaum AND Institute of Ecology and Evolution, Aquatic Ecology, University of Bern.In less than 15,000 years, Lake Victoria cichlid fishes have radiated into as many as 500 different species. Ecological and sexual sel ection are thought to contribute to this ongoing speciation process, but genetic differentiation remains low. However, recent work in visual pigment genes, opsins, has shown more diversity. Unlike neighboring Lakes Malawi and Tanganyika, Lake Victoria is highly turbid, resulting in a long wavelength shift in the light spectrum with increasing depth, providing an environmental gradient for exploring divergent coevolution in sensory systems and colour signals via sensory drive. Pundamilia pundamila and Pundamilia nyererei are two sympatric species found at rocky islands across southern portions of Lake Victoria, differing in male colouration and the depth they reside. Previous work has shown species differentiation in colour discrimination, corresponding to divergent female preferences for conspecific male colouration. A mechanistic link between colour vision and preference would provide a rapid route to reproductive isolation between divergently adapting populations. This link is tested by experimental manip ulation of colour vision - raising both species and their hybrids under light conditions mimicking shallow and deep habitats. We quantify the expression of retinal opsins and test behaviours important for speciation: mate choice, habitat preference, and fo raging performance