Publications by authors named "Hanja B Brandl"

The stress response helps individuals cope with challenges, yet how individual stress levels shape group-level processes and the behaviour of other group members has rarely been explored. In social groups, stress responses can be buffered by others or transmitted to members that have not even experienced the stressor first-hand. Stress transmission, in particular, can have profound consequences for the dynamics of social groups and the fitness of individuals therein.

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Article Synopsis
  • Major climate changes and animal movement may lead to the spread of parasites and their vectors, affecting population persistence.
  • Parasites can adapt to new hosts and environments, impacting the growth of these hosts, with one example being the air sac nematode in great tits in Slovakia.
  • In a study in southern Germany, researchers found the nematode infecting four new bird species and recommend further research due to the potential risks to their populations.
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Parasites can impact the behavior of animals and alter the interplay with ecological factors in their environment. Studying the effects that parasites have on animals thus requires accurate estimates of infections in individuals. However, quantifying parasites can be challenging due to several factors.

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The stress systems are powerful mediators between the organism's systemic dynamic equilibrium and changes in its environment beyond the level of anticipated fluctuations. Over- or under-activation of the stress systems' responses can impact an animal's health, survival and reproductive success. While physiological stress responses and their influence on behaviour and performance are well understood at the individual level, it remains largely unknown whether-and how-stressed individuals can affect the stress systems of other group members, and consequently their collective behaviour.

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Background: So far, large numbers of studies investigating the microbiome have focused on gut microbiota and less have addressed the microbiome of the skin. Especially in avian taxa our understanding of the ecology and function of these bacteria remains incomplete. The involvement of skin bacteria in intra-specific communication has recently received attention, and has highlighted the need to understand what information is potentially being encoded in bacterial communities.

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The social decisions that individuals make-who to interact with and how frequently-give rise to social structure. The resulting social structure then determines how individuals interact with their surroundings-resources and risks, pathogens and predators, competitors and cooperators. However, despite intensive research on (a) how individuals make social decisions and (b) how social structure shapes social processes (e.

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Animals time reproductive events to overlap with periods of favorable environmental conditions. However, weather conditions can be unpredictable. Young animals may be particularly susceptible to extreme weather during sensitive developmental periods.

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Many animals live and breed in colonies, and yet, with just a few exceptions, the value of the social bonds between colony members has rarely been examined. Social ties are important for group coordination at collective tasks, and social coordination can facilitate synchronized reproduction among colony members. Synchronized reproduction in turn can amplify the benefits of coloniality, such as social foraging and predator avoidance.

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Early-life experience can fundamentally shape individual life-history trajectories. Previous research has suggested that exposure to stress during development causes differences in social behaviour later in life. In captivity, juvenile zebra finches exposed to elevated corticosterone levels were less socially choosy and more central in their social networks when compared to untreated siblings.

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Bacteria play a central role in animal health. Yet, little is known about the acquisition of bacteria and the extent to which bacteria are acquired from different environmental sources. For example, bird nests host diverse bacteria associated with the eggs, nestlings and nesting material, but previous research has typically focussed on only a limited number of nest components at a time.

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Dendrobatidae (dart-poison frogs) exhibit some of the most complex spatial behaviors among amphibians, such as territoriality and tadpole transport from terrestrial clutches to widely distributed deposition sites. In species that exhibit long-term territoriality, high homing performance after tadpole transport can be assumed, but experimental evidence is lacking, and the underlying orientation mechanisms are unknown. We conducted a field translocation experiment to test whether male , a dendrobatid frog with paternal extra-territorial tadpole transport, are capable of homing after experimental removal, as well as to quantify homing success and speed.

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Background: Gastrointestinal bacteria play a central role in the health of animals. The bacteria that individuals acquire as they age may therefore have profound consequences for their future fitness. However, changes in microbial community structure with host age remain poorly understood.

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