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The analyses of Plio-Pleistocene speciation processes in the Horn of Africa are relevant for understanding the evolution of biodiversity patterns of this understudied part of the world. Here we analyse comprehensive genomic and morphological data of the recently delimited murid genus Ochromyscus , one of the few with Afro-Arabian distribution. Using an integrative taxonomic approach, we delimit three species in the genus: two in eastern Africa (O. brockmani and O. niveiventris) and one in southern Arabia (O. yemeni), and detail their distribution, genetic structure, and evolutionary history. Despite their morphological similarity, the three species split before the Pleistocene, and their interspecific genetic divergence level is comparable to that between sister genera of murine rodents. The split between two taxa living on opposite sides of the Red Sea (O. brockmani vs. O. yemeni) is younger than the separation of their ancestor and O. niveiventris living in eastern Africa. The colonization of Arabia can be explained either by the presence of a relatively recent continental bridge or by the past occurrence of the genus along the eastern coast of the Red Sea and subsequent spreading through the Sinai Peninsula. [ABSTRACT FROM AUTHOR]

The black rat (Rattus rattus) is a unique model for studying exploratory tactics due to its enormous colonizing potential. Considerable behavioral variability and consistent interindividual differences might help populations inhabit new environments and persist there even under intense pressure. Additionally, the affinity of the black rat for climbing might be another advantage, widening their potential niche. In this study, we describe the exploratory tactics of the black rats when introduced to a novel environment. In the first experiment, we tested 12 rats and calculated repeatability of their behaviors across 12 sessions of an enriched open-field test. We concluded that climbing is a highly repeatable behavior that serves as an important source of interindividual variability. In the second experiment, we tested 24 black rats in a unique L-shaped arena. Each rat was tested twice. We found that the majority of rats distributed their activity evenly, exploring each part of the apparatus for a similar amount of time, thus maximizing their chances of finding resources. Nevertheless, these "even" explorers still greatly differed in their level of activity, orderliness and affinity for climbing, generating large variability. In contrast, the minority of rats concentrated their activity only on a section of the new environment and were therefore characterized as selective explorers. Overall, we concluded that a combination of such exploratory tactics as well as a bias for even explorers enables black rats to quickly colonize new environments and persist there even under unfavorable conditions. [ABSTRACT FROM AUTHOR]

Disgust, considered as one of the basic emotions universally shared across various cultures, has only recently attracted increased research interest. Originally developed as a key component of the behavioural immune system serving to protect the body from infectious pathogens, disgust has taken on other roles such as guiding our moral judgements, political preferences, or even choices of sexual partners. Despite these adaptive roles, disgust may, on the other hand, be responsible for negative social (xenophobia, homophobia) or clinical phenomena (common anxiety disorders such as specific phobias of obsessive-compulsive disorder), thus, a reliable measure of individual tendencies to experience disgust is indispensable. The aim of this study was to develop and analyse a Czech version of the Disgust Scale - Revised, one of the most widely used assessment of disgust propensity. Using a back-translation procedure and a counterbalanced test-retest experimental design, we demonstrated that scores on the Czech measure correlated with those on the English original (test-retest reliability r = 0.82) and both measures were found equivalent (p = 0.019). We also adopted a general linear model to show that the level of disgust is affected by sex, age, and education/occupancy, as women and people with no biology education score significantly higher than men and biologists, respectively. Finally, our data provide support to a bifactor model composed of general disgust taping into all items in addition to three distinct disgust domains., Author(s): Jakub Polák [sup.1] [sup.2] , Eva Landová [sup.1] , Daniel Frynta [sup.1] Author Affiliations: (Aff1) grid.447902.c, National Institute of Mental Health, , Topolová 748, 250 67, Klecany, Czech Republic [...]

Introduction: The administration of questionnaires presents an easy way of obtaining important knowledge about phobic patients. However, it is not well known how these subjective measurements correspond to the patient's objective condition. Our study aimed to compare scores on questionnaires and image evaluation to the objective measurements of the behavioral approach test (BAT) and the neurophysiological effect of spiders extracted from fMRI measurements. The objective was to explore how reliably subjective statements about spiders and physiological and behavioral parameters discriminate between phobics and non-phobics, and what are the best predictors of overall brain activation. Methods: Based on a clinical interview, 165 subjects were assigned to either a "phobic" or low-fear "control" group. Finally, 30 arachnophobic and 32 healthy control subjects (with low fear of spiders) participated in this study. They completed several questionnaires (SPQ, SNAQ, DS-R) and underwent a behavioral approach test (BAT) with a live tarantula. Then, they were measured in fMRI while watching blocks of pictures including spiders and snakes. Finally, the respondents rated all the visual stimuli according to perceived fear. We proposed the Spider Fear Index (SFI) as a value characterizing the level of spider fear, computed based on the fMRI measurements. We then treated this variable as the "neurophysiological effect of spiders" and examined its contribution to the respondents' fear ratings of the stimuli seen during the fMRI using the redundancy analysis (RDA). Results: The results for fear ranks revealed that the SFI, SNAQ, DS-R, and SPQ scores had a significant effect, while BAT and SPQ scores loaded in the same direction of the first multivariate axis. The SFI was strongly correlated with both SPQ and BAT scores in the pooled sample of arachnophobic and healthy control subjects. Discussion: Both SPQ and BAT scores have a high informative value about the subject's fear of spiders and together with subjective emotional evaluation of picture stimuli can be reliable predictors of spider phobia. These parameters provide easy and non-expensive but reliable measurement wherever more expensive devices such as magnetic resonance are not available. However, SFI still reflects individual variability within the phobic group, identifying individuals with higher brain activation, which may relate to more severe phobic reactions or other sources of fMRI signal variability. [ABSTRACT FROM AUTHOR]