ASSISIbf: A new pathway to examine collective behaviours in honeybees

Dissertação de mestrado em Biologia Celular e Molecular, apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.Diabetes mellitus (DM) is a degenerative disease representing one of the greatest concerns to modern global health, and worryingly with its incidence increasing worldwide at epidemic rates. DM is associated with the emergence of a variety of clinical complications, including reproductive dysfunction. Given the extension and multifactorial nature of diabetes-induced physiological changes, it remains unclear what are the mechanisms that may contribute for the reproductive dysfunction described in male diabetic patients. Considering that hyperglycemia has been described as a major effector of the disease pathophysiology, two different in vitro approaches were used to address the isolated effect of high glucose conditions on sperm function and spermatogenesis, thus avoiding other in vivo confounding players. A complete and integrated analysis, through a diversity of important indicators of spermatozoa functionality (motility, viability, capacitation status, acrosomal integrity, mitochondrial superoxide production and mitochondrial membrane potential) suggests that high glucose concentrations does not seem to directly affect spermatozoa, at least in vitro. Organ culture experiments, mimicking the spermatogenic process, determined that high glucose levels increase Sertoli cell number while decreasing tubular luminal area, therefore suggesting an impairment of this somatic cell type with hub importance in spermatogenic control. Taken together, this study suggests that high glucose levels per se seems to influence the male reproductive system only at the spermatogenesis level, stressing the importance of other factors involved in the disease.A Diabetes mellitus (DM) é uma doença degenerativa cuja incidência está a aumentar de forma galopante, sendo actualmente considerada um grave problema de saúde pública. A DM está ainda associada ao surgimento de uma grande variedade de complicações clínicas afectando todos os sistemas de órgãos, não sendo o sistema reprodutor masculino uma excepção. Dada a extensão e natureza multifatorial das alterações fisiológicas induzidas pela DM, permanecem ainda por esclarecer quais os mecanismos responsáveis pela disfunção reprodutora frequentemente reportada em pacientes diabéticos do sexo masculino, incluindo alterações na espermatogénese ou em vários parâmetros seminais. Considerando que a hiperglicémia tem sido descrita como um dos principais efectores das alterações associadas à DM, no presente projecto, foi estudado, através de duas abordagens in vitro distintas, o efeito isolado da hiperglicémia na função espermática e na progressão do processo espermatogénico. Estes sistemas permitiram assim excluir outros factores envolvidos na doença. Uma análise completa e integrada, realizada através da avaliação de uma grande diversidade de importantes indicadores da funcionalidade espermática (mobilidade, viabilidade, estado de capacitação, integridade acrossomal, produção de superóxido mitocondrial e potencial membranar mitocondrial) sugere que, pelo menos in vitro, elevadas concentrações de glucose não afectam directamente o espermatozóide. Os resultados obtidos com um sistema de cultura de órgãos permitiram verificar que elevados níveis de glucose levaram a um aumento do número de células de Sertoli e a uma diminuição da área luminal tubular. Estes resultados sugerem, portanto, uma disfunção neste tipo de células somáticas essenciais para o controlo da espermatogénese. Através deste estudo foi possível verificar e sugerir que a disfunção reprodutora de pacientes do sexo masculino parece não resultar apenas da influência da glucose, apesar de terem sido detectadas alterações ao nível da espermatogénese, sublinhando a importância da natureza multifactorial da doença

Multispecies Communities

Prof. Dr. Jens Schröter, Dr. Pablo Abend und Prof. Dr. Benjamin Beil sind Herausgeber der Reihe. Die Herausgeber*innen der einzelnen Hefte sind renommierte Wissenschaftler*innen aus dem In- und Ausland."Multispecies Communities" sind nicht mehr alleine auf den Menschen fixiert und bringen andere Akteure ins Spiel. Damit ergeben sich neue Formen der Kommunikationen und Kollaborationen, der Verantwortlichkeiten und der Rücksichtnahmen (awareness), der Vergemeinschaftungen und der Teilhaben: Diese finden statt zwischen Menschen und Tieren, Pflanzen und Algorithmen, Artefakten und Biofakten, Maschinen und Medien; zwischen den Sphären von belebt und unbelebt, real und virtuell, unberührt und augmentiert. Der Umgang mit Technik ist längst kein menschliches Privileg mehr, wie die Ausdifferenzierungen von Human-Computer Interaction (HCI) in Animal-Computer Interaction (ACI) oder Plant-Computer Interaction (PCI) verdeutlichen. Diese Ausdifferenzierungen finden ihren Niederschlag ebenso in den verschiedenen Disziplinen der Wissenschaft und in der Kunst sowie in gesellschaftlichen, sozialen, ethischen und politischen Aushandlungen des gemeinsamen Miteinanders. In dieser Ausgabe sind für diesen Diskussionszusammenhang relevante programmatische Texte versammelt und erstmals für den deutschsprachigen Raum zugänglich gemacht."Multispecies communities" are no longer focused on humans alone and bring other actors into play. This results in new forms of communication and collaboration, of responsibilities and awareness, of communalisation and participation: These take place between humans and animals, plants and algorithms, artefacts and biofacts, machines and media; between the spheres of animate and inanimate, real and virtual, untouched and augmented. Dealing with technology is no longer a human privilege, as the differentiations from Human-Computer Interaction (HCI) into Animal-Computer Interaction (ACI) or Plant-Computer Interaction (PCI) exemplify. These differentiations are also reflected in the various disciplines of science and art as well as in societal, social, ethical and political negotiations of shared interaction. In this issue, relevant programmatic texts have been collected for this discussion context and made available for the first time for the German-speaking area

Dynamics of Collective Decision Making of Honeybees in Complex Temperature Fields

Endothermic heat production is a crucial evolutionary adaptation that is, amongst others, responsible for the great success of honeybees. Endothermy ensures the survival of the colonies in harsh environments and is involved in the maintenance of the brood nest temperature, which is fundamental for the breeding and further development of healthy individuals and thus the foraging and reproduction success of this species. Freshly emerged honeybees are not yet able to produce heat endothermically and thus developed behavioural patterns that result in the location of these young bees within the warm brood nest where they further develop and perform tasks for the colony. Previous studies showed that groups of young ectothermic honeybees exposed to a temperature gradient collectively aggregate at the optimal place with their preferred temperature of 36uC but most single bees do not locate themselves at the optimum. In this work we further investigate the behavioural patterns that lead to this collective thermotaxis. We tested single and groups of young bees concerning their ability to discriminate a local from a global temperature optimum and, for groups of bees, analysed the speed of the decision making process as well as density dependent effects by varying group sizes. We found that the majority of tested single bees do not locate themselves at the optimum whereas sufficiently large groups of bees are able to collectively discriminate a suboptimal temperature spot and aggregate at 36uC. Larger groups decide faster than smaller ones, but in larger groups a higher percentage of bees may switch to the sub-optimum due to crowding effects. We show that th

Waiting time after contact.

<p>Shown is the median waiting time (incl. quartiles) in the three different temperature zones after contact with (A) another bee (<i>r_s</i> = 0.5025; p<0.01) and with (B) the arena wall (<i>r_s</i> = 0.0448; p>0.05) (N of contacts = 720).</p

Aggregation process over time.

<p>The graph shows the decision making process over the whole experimental time of 30 minutes. Depicted is the percentage of bees (median and quartiles) in the optimum for groups of 24 and 64 bees. The curves were fitted according to the saturation function .</p

Experimental set-up.

<p>A) Overview over the experimental set-up, consisting of a circular wax arena (a) and two heat-bulbs (b) which generate the thermal gradient. A set of IR-emitters (c) generate light (not visible for honeybees) to allow observations with an IR-Sensible camera (d). B) Schematic drawing of the experimental set-up: Main control unit of the experimental set-up is an standard PC, including a state-of-the-art I/O board. This I/O board controls two multiplexers M, that control the sensor-array in the arena-floor. The data from the sensors is fed back into the I/O-board. Further the IO board controls the two heat-bulbs H (using two digital dimmers D). The image recoded by the camera C is fed into the PC and stored on mass storage devices. Gray solid lines indicate control lines for the multiplexers, black solid lines indicate the data-line from the temperature sensors, grey dashed lines indicate control-lines for the digital dimmers. The bold solid line indicates the video-line from the camera to the PC.</p

Speed of the decision making.

<p>The graph shows the time in minutes (median and quartiles) until the minimum number of bees for a statistically significant decision was reached (p<0.05, MannWhitney U test). The data include trials with 24 and 64 bees.</p

Cluster formation and distribution of bees at homogeneous temperatures.

<p>(A)shows the percentage of bees not in clusters (free bees, FB), bees in small clusters (2–3 bees, SC) and the bees in big clusters (>3 bees, BC) at 29±1°C compared to the free bees, bees in small clusters and bees in big clusters at 36±1°C (-test p<0.05). The data include all groups sizes (24, 128). (B) shows the distribution of bees in the three different evaluation zones (left, outside and right) compared to the predicted distribution of the UDM (-test p>0.05). The data include all groups sizes (24, 128) and temperatures (29±1°C, 36±1°C).</p

Temperature distribution of the different target temperatures in the arena in experiments with a complex gradient.

<p>Measurements of the central sensor of each zone are averaged over all experiments. The temperature distributions are significantly different between all three zones (p<0.05, T test). The targeted temperatures were as follows: outside the zones (blue): 31±1°C; right zone (red): 32±1°C; left zone (yellow): 36±1°C.</p