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

Understanding the Emerging Behaviors and Demands for the Colony Success of Social Insects: A Mathematical Approach

abstract: The most advanced social insects, the eusocial insects, form often large societies in which there is reproductive division of labor, queens and workers, have overlapping generations, and cooperative brood care where daughter workers remain in the nest with their queen mother and care for their siblings. The eusocial insects are composed of representative species of bees and wasps, and all species of ants and termites. Much is known about their organizational structure, but remains to be discovered. The success of social insects is dependent upon cooperative behavior and adaptive strategies shaped by natural selection that respond to internal or external conditions. The objective of my research was to investigate specific mechanisms that have helped shaped the structure of division of labor observed in social insect colonies, including age polyethism and nutrition, and phenomena known to increase colony survival such as egg cannibalism. I developed various Ordinary Differential Equation (ODE) models in which I applied dynamical, bifurcation, and sensitivity analysis to carefully study and visualize biological outcomes in social organisms to answer questions regarding the conditions under which a colony can survive. First, I investigated how the population and evolutionary dynamics of egg cannibalism and division of labor can promote colony survival. I then introduced a model of social conflict behavior to study the inclusion of different response functions that explore the benefits of cannibalistic behavior and how it contributes to age polyethism, the change in behavior of workers as they age, and its biological relevance. Finally, I introduced a model to investigate the importance of pollen nutritional status in a honeybee colony, how it affects population growth and influences division of labor within the worker caste. My results first reveal that both cannibalism and division of labor are adaptive strategies that increase the size of the worker population, and therefore, the persistence of the colony. I show the importance of food collection, consumption, and processing rates to promote good colony nutrition leading to the coexistence of brood and adult workers. Lastly, I show how taking into account seasonality for pollen collection improves the prediction of long term consequences.Dissertation/ThesisDoctoral Dissertation Applied Mathematics 201

From control to constraint: a study of reproduction in the eusocial honeybee and the solitary red mason bee

The major evolutionary transition from solitary to eusocial living is hallmarked by the reproductive division of labour. I investigated mechanisms underlying reproductive control in a solitary bee (Osmia bicornis), with the aim of informing how and why such mechanisms were co-opted into reproductively constraining workers in a eusocial species (Apis mellifera, mrca 95 mya; Peters et al., 2017). I start out by introducing the problems of reproductive constraint and the evolution of eusociality (Chapter 1). In order to test functional links and perform manipulation, it is imperative to establish a reference species within the laboratory. To address the lack of a temperate European solitary model species, I attempted to establish O. bicornis in a laboratory environment (Chapter 3). Preliminary erratic successes of nesting and egg-laying behaviour were achieved, and future recommendations were laid out. To further facilitate O. bicornis as a model species; microsatellite markers were mined, designed, tested and validated in collaboration with the NERC Biomolecular analysis facility in Sheffield (Chapter 4). The broad applicability of these markers is discussed. The capricious nature of laboratory egg-laying necessitated appraising reproductive control directly. To enable assaying oogenesis, I performed the first microstructural study of the O. bicornis ovary (Chapter 5). Since mating plays an important role in the ovary activation of eusocial queens and other insect species, I concurrently examined the effect of mating status on the ovary of O. bicornis (Chapter 5) — with special reference to the potential role of mating status in reproductive constraint. Finally, I investigated how a known mechanism of reproductive constraint (Duncan et al., 2016) operates in the related solitary bee, to ascertain its ancestral role (Chapter 6).The mechanism was found to be reversed in O. bicornis. Chapter 7 places the overall findings within their wider context, and outlines future avenues of research

A complex systems approach to education in Switzerland

The insights gained from the study of complex systems in biological, social, and engineered systems enables us not only to observe and understand, but also to actively design systems which will be capable of successfully coping with complex and dynamically changing situations. The methods and mindset required for this approach have been applied to educational systems with their diverse levels of scale and complexity. Based on the general case made by Yaneer Bar-Yam, this paper applies the complex systems approach to the educational system in Switzerland. It confirms that the complex systems approach is valid. Indeed, many recommendations made for the general case have already been implemented in the Swiss education system. To address existing problems and difficulties, further steps are recommended. This paper contributes to the further establishment complex systems approach by shedding light on an area which concerns us all, which is a frequent topic of discussion and dispute among politicians and the public, where billions of dollars have been spent without achieving the desired results, and where it is difficult to directly derive consequences from actions taken. The analysis of the education system's different levels, their complexity and scale will clarify how such a dynamic system should be approached, and how it can be guided towards the desired performance

Culture and variation in wild chimpanzee behaviour : a study of three communities in West Africa

The concept of culture has recently been used to explain behavioural variation and trans-generational continuity of behaviour in non-human animals and in chimpanzees in particular. However, few studies in the wild have systematically investigated how the environment and behavioural adaptation might influence behavioural diversity. In this context, one habituated community of wild chimpanzees (Pan troglodytes verus) at Bossou, Guinea, and two neighbouring non-habituated communities in the Nimba Mountains region of Guinea and Cote d'Ivoire were the subject of a detailed study of behavioural variation at the intra- and inter-community level. An ecologically-based approach was adopted to investigate variation in nest building, in the use of the oil-palm tree (Elaeis guineensis), in ant-dipping and in tool-choice and -manufacturing. A significant influence of environmental variables on nesting parameters emerged explaining much of the variation observed between the three sites. However, some differences that arose are more likely to reflect differences in social structure and organisation. The comparative study of the utilisation of the oil-palm tree failed to reveal proximate environmental parameters that might explain significant observed variations in use. These findings raise interesting and important questions pertaining to diffusion of behaviour between neighbouring chimpanzee communities. Dipping for driver ants, Dorylus spp., is often cited as one of the best examples of culture in chimpanzees. A detailed analysis of this behaviour at Bossou suggests that risk exposure affects frequency of performance in the developing chimpanzee and reveals a strong influence of prey characteristics, including aggressiveness and/or gregariousness , on tool length and technique employed. Variations in tool-choice and tool-manufacturing within and between three tool-use behaviours at Bossoui nvolving the use of a stick or a stalk were found to be significantly associated with the nature of the task and its predictability, emphasising the importance of environmental affordance and constraints on these processes. In addition, efficiency in behaviour across another set of three tool-use behaviours was explored focusing chiefly on age-class differences. An analysis of individual and community-level patterns of laterality in hand-use between these three tool-use behaviours is also provided. The data supply some evidence to support the selective advantages of lateralization in hand-use with respect to behavioural efficiency. The findings also suggest that haptic tasks have played an important evolutionary role in driving population-level handedness, and reveal that although complex tool-uses exhibited high levels of lateralization, these failed to show task specialisation across individuals. Finally, this thesis presents a comprehensive review analysis of individual and community-wide variation across a range of behaviours observed in chimpanzees and identifies paths and hypotheses that warrant further exploration and testing with the aim to gain further insight into cultural processes in nonhuman animals

Play Among Books

How does coding change the way we think about architecture? Miro Roman and his AI Alice_ch3n81 develop a playful scenario in which they propose coding as the new literacy of information. They convey knowledge in the form of a project model that links the fields of architecture and information through two interwoven narrative strands in an “infinite flow” of real books