Score: 9.2, Published: 2024-02-12
DOI: 10.1101/2024.02.09.579705
The structure of social networks fundamentally influences spreading dynamics. In general, the more contact between individuals, the more opportunity there is for transmission to take place. Yet, contact between individuals, and any resulting transmission events, are determined by a combination of spatial (where individuals choose to move) and social rules (who they choose to interact with or learn from). Here we examine the effect of the social-spatial interface on spreading dynamics using a simulation model. We quantify the relative effects of different movement rules (localized, semi-localized, nomadic, and resource-based movement) and social transmission rules (simple transmission, anti-conformity, proportional, conformity, and threshold rules) to both the structure of social networks and spread of a novel behaviour. Localized movement created weakly connected sparse networks, nomadic movement created weakly connected dense networks, and resource-based movement generated strongly connected modular networks. The resulting rate of spreading varied with different combinations of movement and transmission rules, but--importantly--the relative rankings of transmission rules changed when running simulations on static versus dynamic representations of networks. Our results emphasize that bottom-up social and spatial behaviours influence emergent network structure, and are of particular consequence for the spread of information under complex transmission rules.
Score: 40.6, Published: 2024-01-25
DOI: 10.1101/2023.09.15.558032
Animals have myriad adaptations to help them hunt and feed in the most efficient and effective manner. One mysterious behavior related to hunting and feeding is the posterior toe tapping behavior of some frogs. Biologists and hobbyists alike have long noticed this behavior, but there is little empirical data to explain its causes and consequences. To test the hypothesis that tapping is related to feeding and modulated by environmental context, we conducted a series of related experiments in the Dyeing poison frog, Dendrobates tinctorius. We reasoned that mechanostimulation of prey by vibrational stimuli from tapping might induce prey movement and thereby facilitate prey detection by frogs. We first confirmed that tap rate was higher during feeding as has been observed in other species. Interestingly, this effect was heightened in the presence of a conspecific. We next asked whether frogs tapped less under conditions when vibrational contact between frogs and prey was not possible. Finally, we asked whether D. tinctorius tap more on more vibrationally responsive surfaces and whether prey capture success was higher when tapping. In addition to confirming an association between tapping and feeding, our work demonstrates modulation of toe tapping based on social context, prey accessibility, and substrate characteristics. Significance StatementThe toe tapping of some amphibians is an intriguing behavior that has attracted attention from researchers and hobbyists, yet the functional role of toe tapping remains poorly understood. Previous studies have noted an association between toe tapping and feeding in other species, and our work does so quantitatively and experimentally in Dyeing poison frogs, Dendrobates tinctorius. We demonstrate that frogs modulate tap rate based on the presence of conspecifics, prey accessibility, and substrate type. We suggest tapping may act as a vibrational stimulus to facilitate prey detection and capture alongside other functions.
Score: 3.9, Published: 2024-02-17
DOI: 10.1101/2024.02.14.580392
Associations can be learned incrementally, via reinforcement learning (RL), or stored instantly in working memory (WM). While WM is fast, it is also capacity-limited and effortful. Striatal dopamine may promote RL plasticity, and WM, by facilitating updating and effort exertion. Yet, prior studies have failed to distinguish between dopamine's effects on RL versus WM. N = 100 participants completed a paradigm isolating these systems in a double-blind study measuring dopamine synthesis with [18F]-FDOPA imaging and manipulating dopamine with methylphenidate and sulpiride. Learning is enhanced among high synthesis capacity individuals and by methylphenidate, but impaired by sulpiride. Methylphenidate also blunts effort cost learning. Computational modeling reveals that individuals with high dopamine synthesis rely more on WM, while methylphenidate boosts their RL rates. The D2 antagonist sulpiride reduces accuracy due to diminished WM involvement and faster WM decay. We conclude that dopamine enhances both slow RL, and fast WM, by promoting plasticity and reducing effort sensitivity. These results also highlight the need to control for dopamine's effects on WM when testing its effects on RL.
Score: 5.4, Published: 2024-02-08
DOI: 10.1101/2024.02.08.579429
Microplastics (MPs) are growing and ubiquitous environmental pollutants and represent one of the greatest contemporary challenges caused by human activities. Current research has predominantly examined the singular toxicological effects of individual polymers, neglecting the prevailing reality of organisms confronted with complex contaminant mixtures and potential synergistic effects. To fill this research gap, we investigated the lethal and sublethal effects of two common MPs, polystyrene (PS - 4.8-5.8 m) and poly(methyl methacrylate) (PMMA - 1-40 m), and their combination (MIX), on the pollinating insect Apis mellifera. For each treatment, we evaluated the oral toxicity of two ecologically relevant and one higher concentration (0.5, 5 and 50 mg/L) and analysed their effects on the immune system and worker survival. As immune activation can alter the cuticular hydrocarbon profile of honey bees, we used gas chromatography-mass spectrometry (GC-MS) to investigate whether MPs lead to changes in the chemical profile of foragers and behavioural assay to test whether such changes affect behavioural patterns of social recognition, undermining overall colony integrity. The results indicate a synergistic negative effect of PS and PMMA on bee survival and immune response, even at ecologically relevant concentrations. Furthermore, alterations in cuticle profiles were observed with both MPs at the highest and intermediate concentrations, with PMMA being mainly responsible. Both MPs exposure resulted in a reduction in the abundance of several cuticular compounds. Hive entry guards did not show increased inspection or aggressive behaviour towards exposed foragers, allowing them to enter the colony without being treated differently from uncontaminated foragers. These findings raise concerns not only for the health of individual bees, but also for the entire colony, which could be at risk if contaminated nestmates enter the colony undetected, allowing MPs to spread throughout the hive.
Score: 3.0, Published: 2024-02-15
DOI: 10.1101/2024.02.13.579939
The present study aims to present the design of an electronic nose capable of learning and differentiating semiochemical signals emitted by insects usable to identify species that transmit Chagas disease. The proposed device used different non-specific resistor gas sensors integrated into a system of artificial intelligence models. To validate the nose, we used eight insect species of the Triatominae subfamily and one population that was a natural carrier of the parasite Trypanosoma cruzi. Also, the discriminatory capacity of distant species was tested with other insects like Aedes aegypti (arbovirus vector) and Sitophilus oryzae (stored grains plague). As a result, the electronic nose was able to differentiate up to gender level with an accuracy of 89.64% and to differentiate Rhodnius pallensces naturally infected with T. cruzi with less than 1% of error in classification. These results show that our designed device can detect particular smelling footprints, and one electronic nose like that could be a tool to discriminate against insects in the future.
Score: 2.5, Published: 2024-02-15
DOI: 10.1101/2024.02.15.580445
Soon after birth, naive animals and newborn babies show spontaneous attraction towards faces and face-like stimuli with three dark features representing eyes and a mouth/beak. While neurons selectively responding to faces have been found in the inferotemporal cortex of adult primates, face-selective domains in the brains of young monkeys seem to develop only later in life after exposure to faces. This has fueled a debate on the role of experience in the development of face-detector mechanisms, since face preferences are well documented in naive animals, such as domestic chicks reared without exposure to faces. Here we demonstrate that neurons in a cortex-homologue area of one-week-old face-naive domestic chicks selectively respond to a face-like configuration. Our single-cell recordings show that these face detectors do not respond to alternative configurations or isolated facial features. Moreover, the population activity of face-selective neurons accurately encoded the face-like stimulus as a unique category. Thus, our findings show that face detectors are present in the brains of very young animals without pre-existing experience.
Score: 2.2, Published: 2024-02-12
DOI: 10.1101/2024.02.10.578266
Intraspecific variation in ecologically relevant traits is critical for animal populations to survive in our rapidly changing world. This is especially true for species that suffer from intense harvesting regimes, whereby populations density is often low. Standard hatchery procedures can assist some management and conservation programs by producing large numbers of juveniles to be released into the wild. Yet we know surprisingly little on the impact that such standard, minimalistic settings have on the development of intraspecific variation in important phenotypes of the individuals, including among-individual variation in behavioural (individuality) and life-history traits, and in the plasticity of those traits in response to varying environmental conditions. Here, we fill this gap by testing whether early-life exposure to different environmental conditions alters the development of individuality and plasticity in ecologically relevant behaviours and life-history traits of the European lobster (Homarus gammarus)--one the most harvested species in the Mediterranean, which has been subjected to conservation programs for decades. By accessing one of the largest lobsters hatcheries in Italy, we used the progeny of wild-caught females and manipulated--in a full factorial design--the environmental complexity of the individual enclosures (i.e. presence/absence of substrate and/or shelter) and the level of exposure to cues from their natural predators. We repeatedly quantified behaviours (i.e. activity, refuge use, and aggressiveness) and life-history traits (i.e. carapace length and intermoult period) of the individuals throughout their early development, capturing both mean and individual-level variation across treatments. Our results offer solid evidence that effects of standard hatchery settings extend far beyond mean changes in the behaviour and life history of the animals, compromising the development of individual plasticity in those traits that are essentials for populations to survive in the wild--likely reducing the effectiveness of conservation programs.
Score: 2.0, Published: 2024-02-17
DOI: 10.1101/2024.02.14.580296
Decision-making in mammals is fundamentally based on the integration of several senses. When different sensory inputs guide conflicting outcomes, animals make decisions following the prepotent sensory modality. However, the neural basis of state-dependent flexibility in sensory dominance and multisensory decisions remains obscure. Here, we found that locomotion switched auditory-dominant decisions to visual-dominant ones in mice with audiovisual conflicts. When mice made auditory-dominant decisions, the visual representation in the posterior parietal cortex (PPC) was weakened. Prolonged locomotion restored visual representation in the PPC and induced visually dominant decisions by inhibiting the auditory cortical neurons projecting to the PPC (ACPPC). In contrast, it had no effect on the AC projection to the striatum, which mediated auditory decisions. Locomotion activated the AC-projecting secondary motor cortex neurons, which preferentially inhibited the ACPPC neurons. Our findings demonstrate that animals make flexible multisensory decisions by gating auditory afferents to the association cortex depending on locomotor conditions.
Score: 1.8, Published: 2024-02-17
DOI: 10.1101/2024.02.15.580479
Early life stress (ELS) adversely affects physiological and behavioral outcomes, increasing the vulnerability to stress-related disorders, such as post-traumatic stress disorder (PTSD). PTSD prevalence is significantly higher in women and is partially mediated by genetic risk variants. Understanding how sex influences the interaction of PTSD risk genes, such as FKBP5, with trauma-related behaviors is crucial for uncovering PTSD's neurobiological pathways. The development of in-depth behavioral analysis tools using unsupervised behavioral classification is thereby a crucial tool to increase the understanding of the behavioral outcomes related to stress-induced fear memory formation. The current study investigates the sex-specific effects of ELS exposure by using the limited bedding and nesting (LBN) paradigm. The LBN exposure disrupted different facets of the hypothalamic-pituitary-adrenal (HPA) axis in a sex-specific manner directly after stress and at adult age. Moreover, freezing was altered by LBN exposure in both the acquisition and the retrieval of fear in a sex-dependent manner. Unsupervised behavioral analysis revealed a higher active fear response after LBN exposure during fear acquisition in females, but not in males. The regulation of the HPA axis is closely intertwined with cellular metabolism and core regulatory cascades. To investigate the impact of LBN exposure on tissue-specific metabolism, a metabolomic pathway analysis in the basolateral amygdala revealed a specific sex- and stress-dependent effect on purine, pyrimidine, and glutamate metabolism. The present study highlights the intricate interplay between metabolic pathways and the neurobiological substrates implicated in fear memory formation and stress regulation. Overall, these findings highlight the importance of considering sex-specific metabolic alterations in understanding the neurobiological mechanisms underlying stress-related disorders and offer potential avenues for targeted interventions.
Score: 1.8, Published: 2024-02-15
DOI: 10.1101/2024.02.15.578887
Anthropogenic noise is considered one of the most serious forms of pollution globally and has been shown to have negative effects on the distribution, behaviour, cognition and reproductive success of animal species worldwide. One of the most well researched impacts of anthropogenic noise is its effect on acoustic communication. Animals may adjust the rate, amplitude, duration, and/or frequency of their acoustic signals to better maintain communication when anthropogenic noise is present. In this study, we combine behavioural focals, amplitude measurements and audio recordings to investigate how female Western Australian magpies (Gymnorhina tibicen dorsalis) alter the acoustic features of their territorial song (known as a carol) when anthropogenic noise is present. Magpies reduced the rate at which they carolled when loud anthropogenic noise was present, and increased their peak frequency during anthropogenic noise, but, contrary to our hypotheses did not alter the amplitude, duration, or other frequency parameters of their carols. Results from this study add to the growing body of literature documenting changes to the vocal behaviour of wildlife in the presence of anthropogenic noise and highlights the importance of investigating multiple acoustic parameters to understand how species adjust their vocalisations in response to this pollutant.