Biology subjects

Behrmann-Godel, J.

Publications and source records attributed to Behrmann-Godel, J..

3 recordsLinked to original sources

bioRxiv2023

Unravelling the origins of boldness: A common garden experiment with cave fish (Barbatula barbatula)

Many animals show an aversion to bright, open spaces, with significant variability seen across species, populations, and individuals within populations. Although there is much interest in the underlying causes of this behaviour, few studies have been able to systematically isolate the role of heritable and environmental effects. Here we addressed this gap using a common garden experiment with cave fish. Specifically, we bred and cross-bred cave loaches (Barbatula barbatula) in the lab, raised the offspring in complete darkness or normal light conditions, and studied their light avoidance behaviour. Cave fish spent much more time in a light area and ventured further out, while surface fish spent considerable time on the edge between light and dark areas. Hybrids behaved most similarly to cave fish. Light treatment and eye size and quality only had a modest effect. Our results suggest light avoidance behaviour of cave fish has a heritable basis and is fundamentally linked to increased boldness rather than reduced vision, which is likely adaptive given the complete lack of macropredators in the cave environment. Our study provides novel experimental insights into the behavioural divergence of cave fish and contributes to our broader understanding of the evolution of boldness and behavioural adaptation.

animal behavior and cognition↗

bioRxiv2023

Phenotypic plasticity and genetic differentiation drive troglomorphic character development in European cave loach

Using a cross-fostering experiment, we provide evidence for the contribution of both genetic differentiation and phenotypic plasticity to troglomorphic character development in the recently discovered cave form of Barbatula barbatula, an evolutionarily young lineage and first cavefish described in Europe, the northernmost record. We established reproducing populations of cave- and surface-dwelling loaches to produce cave, surface, and hybrid offspring and reared the F1 fish in a common garden setting in total darkness (DD) to simulate cave conditions as well as under the natural photoperiod (DL). We observed significant differences in the occurrence and extent of typical troglomorphic target characters among the offspring groups. Regardless of rearing conditions, cave fish exhibited smaller eyes, lighter body coloration, longer barbels, and larger olfactory epithelium than seen in surface fish. Hybrids in both rearing conditions generally showed an intermediate level of these traits. Surface and hybrid DD fish differed from the DL groups, resembling the cave fish phenotype in several traits, including eye size and body pigmentation. In contrast, cave and hybrid DL fish groups resembled surface fish phenotypes. Results confirmed that troglomorphic traits arise from heritable genetic differentiation of cave from surface forms and that phenotypic plasticity contributes to the process of adaptation to novel light conditions.

evolutionary biology↗

bioRxiv2019

Schistocephalus parasite infection alters sticklebacks' movement ability and thereby shapes social interactions

Parasitism is ubiquitous in the animal kingdom. Although many fundamental aspects of host-parasite relationships have been unravelled, few studies have systematically investigated how parasites affect organismal movement. Here we combine behavioural experiments of Schistocephalus solidus infected sticklebacks with individual-based simulations to understand how parasitism affects individual movement ability and how this in turn influences social interaction patterns. Detailed movement tracking revealed that infected fish swam slower, accelerated slower, turned more slowly, and tended to be more predictable in their movements than did non-infected fish. Importantly, the strength of these effects increased with increasing parasite load (% of body weight), with the behaviour of more heavily infected fish being more impaired. When grouped, pairs of infected fish moved more slowly, were less cohesive, less aligned, and less coordinated than healthy pairs. Mixed pairs exhibited intermediate behaviours and were primarily led by the non-infected fish. These social patterns emerged naturally in model simulations of self-organised groups composed of individuals with different speeds and turning tendency, consistent with changes in mobility and manoeuvrability due to infection. Together, our results demonstrate how infection with a complex life cycle parasite affects the movement ability of individuals and how this in turn shapes social interactions, providing important mechanistic insights into the effects of parasites on host movement dynamics.

animal behavior and cognition↗