Animal Behavior Research Articles

Coloured feeder balls and mirrors increase exploring behaviour in captive common marmosets (Callithrix jacchus)

The influence of visual enrichment on the behaviour and welfare of captive animals is still little studied for many species due to variations in ability to distinguish colours. Common marmosets make an interesting model of study because all males are dichromats and cannot distinguish red from green and only some females have trichromatic vision. The behaviour of six common marmosets at Tynemouth Aquarium, UK (three males, three females) was monitored under standard structural and feeding enrichment conditions and in the presence of a mirror and 12 coloured puzzle feeder balls, with and without food, using continuous scan observation with one-zero recording rule (6 hrs/ condition). The number of interactions with each item was also recorded. The relative frequency of exploring increased and that of social interaction decreased significantly in the presence of the new enrichment items. The mirror attracted around ten times more interest than any colour on days with empty feeder balls. However, the food-filled balls attracted up to five times more interest than the mirror, with the red, orange and pink balls tallying the largest number of interactions (555, 369 and 176, respectively) followed by the green (116), yellow (99) and blue (90) balls, suggesting the presence of trichromacy in at least one of the females in the group. This study added to the existing evidence that mirrors and coloured puzzle feeder balls can provide additional cognitive stimulation and represent effective enrichment items for increasing exploring behaviour and possibly improving the welfare of captive New World primates.

A Novel Astrocyte-Neuron Interaction to Control Complex Animal Behavior.

A Novel Astrocyte-Neuron Interaction to Control Complex Animal Behavior.

Low-Cost Approaches in Neuroscience to Teach Machine Learning Using a Cockroach Model.

In an effort to increase access to neuroscience education in underserved communities, we created an educational program that utilizes a simple task to measure place preference of the cockroach (Gromphadorhina portentosa) and the open-source free software, SLEAP Estimates Animal Pose (SLEAP) to quantify behavior. Cockroaches (n = 18) were trained to explore a linear track for 2 min while exposed to either air, vapor, or vapor with nicotine from a port on one side of the linear track over 14 d. The time the animal took to reach the port was measured, along with distance traveled, time spent in each zone, and velocity. As characterizing behavior is challenging and inaccessible for nonexperts new to behavioral research, we created an educational program using the machine learning algorithm, SLEAP, and cloud-based (i.e., Google Colab) low-cost platforms for data analysis. We found that SLEAP was within a 0.5% margin of error when compared with manually scoring the data. Cockroaches were found to have an increased aversive response to vapor alone compared with those that only received air. Using SLEAP, we demonstrate that the x-y coordinate data can be further classified into behavior using dimensionality-reducing clustering methods. This suggests that the linear track can be used to examine nicotine preference for the cockroach, and SLEAP can provide a fast, efficient way to analyze animal behavior. Moreover, this educational program is available for free for students to learn a complex machine learning algorithm without expensive hardware to study animal behavior.Significance Statement This method demonstrates a novel utilization of machine learning using free cloud-based programming to analyze cockroach behavior in a linear track. This educational program can be implemented in the classroom as a low-cost tool to teach neuroscience and machine learning. Further, implementing these computational tools allows students to explore important questions in behavioral neuroscience, such as learning and memory, drug seeking, and exploratory locomotor behavior.

Research Progress for the Toxic Effects of Microplastics on Soil Animals and Plants

Terrestrial ecosystems represent the most direct and principal reservoirs of plastic contamination on Earth. The toxic effects of microplastic exposure on terrestrial plants have been analyzed from the perspectives of direct toxicity, indirect toxicity, and combined toxicity with other pollutants. By investigating the impacts on the growth, behavior, and oxidative stress responses of soil animals, the toxicological patterns of microplastics have been elucidated. Moreover, the primary factors influencing the toxicity of microplastics on both fauna and flora have been discussed based on current research. The results indicated that for the majority of terrestrial plants, microplastics could inhibit seed germination, adhere to root surfaces, enter the plant body and induce oxidative stress, inhibit photosynthesis, and cause cellular and genetic toxicity. Soil animals could ingest and accumulate microplastics to varying extents, resulting in toxic effects such as aberrant gene expression, oxidative stress, intestinal toxicity, and alterations of growth and behavior on the genetic, cellular, tissue, and individual levels. Furthermore, these effects were also linked to microplastic additives and the adsorbed pollutants. The impact of microplastics on terrestrial plants and animals at environmentally relevant concentrations cannot be overlooked, with particle size emerging as a critical factor influencing toxic effects. The findings provide a basis for assessing the ecological risks of microplastics in soil environments and offer insights into future research directions.

Experimental Study of Animal’s Behavior under the Influence of an Electromagnetic Field of the 5G Mobile Communication Standard

A pilot experimental study was carried out to assess the effect of an unmodulated and modulated electromagnetic field of the 5G mobile communication standard on the central nervous system of animals. Mature male Wistar rats were exposed to electromagnetic fields with a frequency of 4.9 GHz and an intensity of 250 MW/cm2 for 15 days for 2 hours a day. The animals of the two irradiated groups and the control group were in identical conditions in a semi-anechoic shielded chamber. The effect of the electromagnetic field on the functional state of the central nervous system was assessed by a comprehensive analysis of behavior patterns in the “open field” test before and after irradiation. The study did not reveal clear differences in animal behavior when exposed to an unmodulated and modulated 5G electromagnetic field. Statistically significant changes in animal behavior were recorded in the dynamics of the experiment in two irradiated and control groups, which may be due to a change in the natural electromagnetic background in a semi-anechoic shielded chamber.

Brain region-specific neural activation by low-dose opioid promotes social behavior.

The opioid system plays crucial roles in modulating social behaviors in both humans and animals. However, the pharmacological profiles of opioids regarding social behavior and their therapeutic potential remain unclear. Multiple pharmacological, behavioral, and immunohistological c-Fos mapping approaches were used to characterize the effects of μ-opioid receptor agonists on social behavior and investigate the mechanisms in naive mice and autism spectrum disorder-like (ASD-like) mouse models, such as prenatally valproic acid-treated mice and Fmr1-KO mice. Here, we report that low-dose morphine, a μ-opioid receptor agonist, promoted social behavior by selectively activating neurons in prosocial brain regions, including the nucleus accumbens, but not those in the dorsomedial periaqueductal gray (dmPAG), which are only activated by analgesic high-dose morphine. Critically, intra-dmPAG morphine injection counteracted the prosocial effect of low-dose morphine, suggesting that dmPAG neural activation suppresses social behavior. Moreover, buprenorphine, a μ-opioid receptor partial agonist with less abuse liability and a well-established safety profile, ameliorated social behavior deficits in two mouse models recapitulating ASD symptoms by selectively activating prosocial brain regions without dmPAG neural activation. Our findings highlight the therapeutic potential of brain region-specific neural activation induced by low-dose opioids for social behavior deficits in ASD.

The Melatonin Type 2 Receptor Agonist IIK7 Attenuates and Reverses Morphine Tolerance in Neuropathic Pain Rats Through the Suppression of Neuroinflammation in the Spinal Cord

Background: Morphine analgesic tolerance (MAT) limits the clinical application of morphine in the management of chronic pain. IIK7 is a melatonin type 2 (MT2) receptor agonist known to have antioxidant properties. Oxidative stress is recognized as a critical factor in MAT. This study sought to assess the impact of IIK7 on the progression of MAT and its potential to reverse pre-existing MAT. Methods: Wistar rats underwent partial sciatic nerve transection (PSNT) surgery to induce neuropathic pain (NP). Seven days post nerve transection, we implanted an intrathecal (i.t.) catheter and linked it to an osmotic pump. Rats were randomly divided into the following groups: sham-operated/vehicle, PSNT/vehicle, PSNT/IIK7 50 ng/h, PSNT/MOR 15 g/h, and PSNT/MOR 15 g + IIK7 50 ng/h. We implanted two i.t. catheters for drug administration and the evaluation of the efficacy of IIK7 in reversing pre-established MAT. We linked one to an osmotic pump for MOR or saline continuous i.t. infusion. On the 7th day, the osmotic pump was disconnected, and 50 μg of IIK7 or the vehicle was administered through the second catheter. After 3 h, 15 μg of MOR or saline was administered, and the animal behavior tests were performed. We measured the levels of mRNA for Nrf2 and HO-1, pro-inflammatory cytokines (PICs), and the microglial and astrocyte activation in the spinal cord. Results: The co-administration of IIK7 with MOR delayed MAT development in PSNT rats by restoring Nrf2 and HO-1 while also inhibiting the microglial-cell and astrocyte activation, alongside the suppression of PICs. Additionally, a single injection of high-dose 50 μg IIK7 was efficient in restoring MOR’s antinociception in MOR-tolerant rats. Conclusions: Our results indicate that the co-infusion of ultra-low-dose IIK7 can delay MAT development and a high dose can reverse pre-existing MAT.

Personality expression is shaped by the early experienced social context in predatory mites.

Research Highlights: Schausberger, P., & Nguyen, T. H. (2024). Early social isolation disrupts adult personality expression in group-living mites. Journal of Animal Ecology. https://doi.org/10.1111/1365-2656.14169. Personality traits in animals have been of great interest in the last decades. The number of studies demonstrating the existence of personality in a wide range of taxa is growing rapidly. Although the effect of early experience on later average values of behavioural traits is well documented, very few articles demonstrate the effects of those factors on personality expression itself. One factor in particular received very little, if not no, attention: social isolation. Although social isolation is known to have major impacts on later animal behaviour, it is still unknown whether it may favour or inhibit personality expression. In a recent study, Schausberger and Nguyen (2024) demonstrated that early-life social isolation had strong effects on adults of the predatory mite Phytoseiulus persimilis. They show for the first time that early social isolation decreased the expression of personality in the activity of adults when tested in a social context. Interestingly, they observed the opposite effect when the same mites were tested alone:previously isolated mites were highly repeatable but group-reared mites were not. Finally, they also show an indirect effect of early social isolation through mating: mating with a male who experienced social isolation increased the behavioural repeatability of females. This study not only reinforces the established understanding of personality but also paves the way for future research in the field.

Evaluation of a user-friendly CSDS cage apparatus for studying depressive-like behaviors in rodents.

Previously, a chronic social defeat stress (CSDS) model has been widely-adopted for assessing depressive-like behaviors in animals. However, there is still room for improvement in the CSDS model to safeguard study accuracy and the welfare of lab rodents. Our study team developed a novel, standardized apparatus to induce CSDS in rodents and assessed the model's practical adaptability. An innovative CSDS cage apparatus and water bottle was designed. To evaluate the effectiveness of the newly developed tools, a variety of animal models, including the tail suspension test (TST), sucrose preference test, forced swimming test (FST), novelty-suppressed feeding test, female urine sniffing test, and open field test (OFT), were adopted to assess depressive-like behaviors in mice. Fluoxetine treatment was also administered to observe the reversal effect, as part of the validation. The CSDS cage apparatus resulted in the manifestation of depressive-like behaviors in the model mice. Significant reductions in sucrose preference and urine sniffing time were observed, while the OFT revealed decreased central zone total distance, residence time, and frequency of entry. Moreover, increased immobility was found in the FST and TST. Fluoxetine treatment was found to successfully reverse the modeling effect. The CSDS cage apparatus was validated for enhanced usability and addressed the previous challenges of water bottle leakage and lab rodent welfare issues. The consistent results from multiple behavioral tests also supported real-world application of the apparatus, offering researchers a promising alternative to conventional rodent cages.

Evaluation of Different Sensor Systems for Classifying the Behavior of Dairy Cows on Pasture

Monitoring animal behavior using sensor technologies requires prior testing under varying conditions because behaviors can differ significantly, such as between grazing and confined cows. This study aimed to validate several sensor systems for classifying rumination and lying behaviors in cows on pasture under different environmental conditions, compare the sensors’ performance at different time resolutions, and evaluate a correction algorithm for rumination data. Ten Simmental dairy cows were monitored on pasture, each simultaneously equipped with an ear-tag accelerometer (ET), two different leg-mounted accelerometers (LMs), and a noseband sensor (NB). Indirect visual observations using drone-recorded video footage served as the gold standard for validation. The concordance correlation coefficient (CCC) for rumination time was very high for both the ET and NB (0.91–0.96) at a 10 min time resolution. Applying the correction algorithm to 1 min data improved the CCC for the NB from 0.68 to 0.89. For lying time, the CCC was moderate for the ET (0.55) but nearly perfect for both LMs (0.99). In conclusion, both sensors evaluated for classifying rumination are suitable for cows on pasture. We recommend using a correction algorithm for 1 min NB data. For the measurement of lying time, the LMs significantly outperformed the ET.

Tangeretin exerts and modulates the anxiolytic effects of the GABAkine drugs diazepam and flumazenil in mice: Molecular interventions through animal behavior and molecular dynamic simulations

Tangeretin exerts and modulates the anxiolytic effects of the GABAkine drugs diazepam and flumazenil in mice: Molecular interventions through animal behavior and molecular dynamic simulations

"Broadening Perspectives Activities" Improve LGBTQ+ Student Experiences and Religious Students' Content Comprehension.

Curricular content in undergraduate biology courses has been historically hetero and cisnormative due to various cultural stigmas, biases, and discrimination. Such curricula may be partially responsible for why LGBTQ+ students in STEM are less likely to complete their degrees than their non-LGBTQ+ counterparts. We developed Broadening Perspective Activities (BPAs) to expand the representation of marginalized perspectives in the curriculum of an online, upper-division, undergraduate animal behavior course, focusing on topics relating to sex, gender, and sexuality. We used a quasiexperimental design to assess the impact of the BPAs on student perceptions of course concepts and on their sense of belonging in biology. We found that LGBTQ+ students entered the course with a better understanding of many animal behavior concepts that are influenced by cultural biases associated with sex, gender, and sexuality. However, LGBTQ+ students who took the course with the BPAs demonstrated a greater sense of belonging in biology at the end of the term compared with LGBTQ+ students in the course without BPAs. We also show that religious students demonstrated improved comprehension of many concepts related to sex, gender, and sexuality after taking the course with BPAs, with no negative impacts on their sense of belonging.

Animal Behaviour Best Paper Prizes 2024

Animal Behaviour Best Paper Prizes 2024

Taking cues from ecological and evolutionary theories to expand the landscape of disgust.

Behavioural avoidance of parasites in the environment generates what is known as the 'landscape of disgust' (analogous to the predator-induced 'landscape of fear'). Despite the potential for improving our inference of host-parasite dynamics, three limitations of the landscape of disgust restrict the insight that is gained from current research: (i) many host-parasite systems will not be appropriate for invoking the landscape of disgust framework; (ii) existing research has primarily focused on immediate choices made by hosts on small scales, limiting predictive power, generalizability, and the value of the insight obtained; and (iii) relevant ecological and evolutionary theory has yet to be integrated into the framework, challenging our ability to interpret the landscape of disgust within the context of most host-parasite systems. In this review, we explore the specific requirements for implementing a landscape of disgust framework in empirical systems. We also propose greater integration of habitat selection and evolutionary theories, aiming to generate novel insight, by exploring how the landscape of disgust varies within and across generations, presenting opportunities for future research. Despite interest in the impacts of parasitism on animal movement and behaviour, many unanswered questions remain.

Plastic Behaviour Buffers Climate Variability in the Wandering Albatross.

Climate change has marked effects on global weather patterns and oceanic systems, impacting animal behaviour and fitness in potentially profound ways. Despite this, we lack detailed information about species' responses to climatic variation. Using an 11-year tracking dataset of over 300 individual birds, we explore the consequences of variation in the southern annular mode (SAM) and southern oscillation index (SOI) for individual behaviour and fitness in wandering albatrosses Diomedea exulans breeding in the Southern Indian Ocean. Our results reveal distinct responses between males and females to climatic variation that align with the impacts of each climatic index on the distinct foraging ranges of each sex. In positive SAM phases, linked to poorer foraging conditions in female ranges and better conditions in male ranges, females exhibited behaviour consistent with reduced foraging success: that is, fewer prey capture attempts and more movement between feeding patches. Males, on the other hand, showed no behavioural change. During positive SOI phases, associated with good foraging conditions in both male and female foraging ranges, both sexes showed evidence of more successful foraging, with birds engaging in more search behaviour, and taking shorter trips with fewer prey capture attempts, together indicating increased food intake per unit time. We found limited evidence for a role of individual variation, as measured through differences in personality, suggesting that plastic responses to climate are sufficiently important so as to obscure inter-individual variation. Supporting this was the finding that individual breeding success was unaffected by climatic variation, suggesting that plastic foraging behaviour allows albatrosses to mitigate climate impacts and maintain reproductive output.

Modified neuroimmune processes and emotional behaviour in weaned and late adolescent male and female mice born via caesarean section

Elective and emergency Caesarean section (C-section) procedures are on the rise, exceeding the recommended guidelines by the World Health Organization. Higher morbidities and long-term health conditions are correlated to C-section deliveries, including neurodevelopmental disorders. During C-section delivery, newborns are not exposed to the vaginal commensal flora, which impedes the early establishment of the gut microbiota. The latter is essential for adequate neuro-immune processes to take place during infancy. In this study, we used a validated model of mice born by C-section (CSD), which mimics clinical observations of dysregulated gut microbiota. Animals were either born naturally or by CSD, before being adopted by dams who underwent delivery within the 12 preceding hours. Behavioural analyses were conducted at post-natal day (PND) 21 and 55. Our results indicate that animals born by C-section present significantly higher body weight in late (PND40-P53) but not early adolescence (PND21-P27), compared to animals born by vaginal delivery (VD). Male animals delivered by C-section presented significantly lower exploration time of the novel arm in the Y Maze test at PND55. However, at PND21, abnormal social interaction was witnessed in male and female animals born by CSD, with significantly decreased time spent interacting during the social interaction test. At both PND21 and PND55, animals from both sexes born by C-section presented significantly decreased time spent in the open arm of the Elevated Plus Maze test, compared to control animals. We then measured the expression of genes associated to neuroimmune interactions (microglia phenotype), inflammatory mediators and lipids in several brain structures of VD and CSD mice at PND21 and PND55. At weaning, animals born by CSD presented altered microglia, inflammatory and lipid metabolism signatures, with increased expression of Cd36, Csf1r and Tnfα in different brain regions of males, but not in females. At PND64, Csf1r, Tmem119 as well as C3ar1 were significantly increased in males born by C-section, but not in females. In males born by vaginal delivery, the expression of Cd36 at PND64 was correlated to anxiety at PND55, whilst a correlation between the expression of Clec7a and the number of head dippings in the elevated plus maze was also noted in males born by CSD. Altogether, our study shows altered emotional behaviour in animals delivered by CSD, which is likely explained by underlying neuro-inflammatory processes in different brain regions. Our work further supports the long-term consequences of CSD on brain health.

Depression-like effects induced by chronic unpredictable mild stress in mice are rapidly reversed by a partial negative allosteric modulator of mGlu5 receptor, M-5MPEP.

Due to the numerous limitations of ketamine as a rapid-acting antidepressant drug (RAAD), research is still being conducted to find an effective and safe alternative to this drug. Recent studies indicate that the partial mGlu5 receptor negative allosteric modulator (NAM), 2-(2-(3-methoxyphenyl)ethynyl)-5-methylpyridine (M-5MPEP), has therapeutic potential as an antidepressant. The study aimed to investigate the potential rapid antidepressant-like effect of M-5MPEP in a mouse model of depression and to determine the mechanism of this action. Chronic unpredictable mild stress (CUMS) was used as an animal model of depression. The effects of single and four-day administration of M-5MPEP on CUMS-induced animal behaviors reflecting anhedonia, apathy, and helplessness were studied. Western blot was applied to measure the levels of proteins potentially involved in a rapid antidepressant effect, including mammalian target of rapamycin (mTOR), eukaryotic elongation factor 2 (eEF2), tropomyosin receptor kinase B (TrkB), and serotonin transporter (SERT), both in the hippocampus and the prefrontal cortex (PFC). Furthermore, excitatory synaptic transmission and long-term potentiation (LTP) were measured in the medial PFC (mPFC). We showed that M-5MPEP administration for four consecutive days abolished CUMS-induced apathy- and anhedonia-like symptoms in a mouse model of depression. We also found that these effects were accompanied by changes in hippocampal TrkB levels and mTOR and eEF2 levels in the PFC. Using electrophysiological techniques, we showed that the four-day M-5MPEP treatment reversed chronic stress-induced increases in excitatory synaptic potential and CUMS-impaired LTP in the mPFC. Partial mGlu5 receptor NAM, M-5MPEP, appears to be a potentially effective new RAAD and deserves further study.

Unsupervised classification of Blanding's turtle (Emydoidea blandingii) behavioural states from multi-sensor biologger data.

Classifying animal behaviors in their natural environments is both challenging and ecologically important, but the use of biologgers with multiple sensors has significantly advanced this research beyond the capabilities of traditional methods alone. Here, we show how biologgers containing an integrated tri-axial accelerometer, GPS logger and immersion sensor were used to infer behavioural states of a cryptic, freshwater turtle, the Blanding's turtle (Emydoidea blandingii). Biologgers were attached to three males and five females that reside in two undisturbed coastal marshes in northeastern Georgian Bay (Ontario, Canada) between May and July 2023. Raw acceleration values were separated into static and dynamic acceleration and subsequently used to calculate overall dynamic body acceleration (ODBA) and pitch. The unsupervised Hidden Markov Model (HMM) successfully differentiated five behavioural states as follows: active in water, resting in water, active out of water, resting in water, and nesting. Overall accuracy of the classification was 93.8%, and except for nesting (79%), all other behaviours were above 92%. There were significant differences in daily activity budgets between male and female turtles, with females spending a greater proportion of time active out of water, and inactive out of the water, while males spent a greater proportion of time active in water. These differences were likely a result of large seasonal life-history requirements such as nesting and mate finding. Accurate classification of behavioural states is important for researchers to understand fine-scale activities carried out during the active season and how environmental variables may influence the behaviours of turtles in their natural habitats.

SwaRmverse: An R package for the comparative analysis of collective motion

Abstract Collective motion, that is the coordinated spatial and temporal organisation of individuals, is a core element in the study of collective animal behaviour. The self‐organised properties of how a group moves influence its various behavioural and ecological processes, such as predator–prey dynamics, social foraging and migration. However, little is known about the inter‐ and intra‐specific variation in collective motion. Despite the significant advancement in high‐resolution tracking of multiple individuals within groups, providing collective motion data for animals in the laboratory and the field, a framework to perform quantitative comparisons across species and contexts is lacking. Here, we present the swaRmverse package. Building on two existing R packages, trackdf and swaRm, swaRmverse enables the identification and analysis of collective motion ‘events’, as presented in Papadopoulou et al. (2023), creating a unit of comparison across datasets. We describe the package's structure and showcase its functionality using existing datasets from several species and simulated trajectories from an agent‐based model. From positional time‐series data for multiple individuals (x‐y‐t‐id), swaRmverse identifies events of collective motion based on the distribution of polarisation and group speed. For each event, a suite of validated biologically meaningful metrics are calculated, and events are placed into a ‘swarm space’ through dimensional reduction techniques. Our package provides the first automated pipeline enabling the analysis of data on collective behaviour. The package allows the calculation and use of complex metrics for users without a strong quantitative background and will promote communication and data‐sharing across disciplines, standardising the quantification of collective motion across species and promoting comparative investigations.

Tracking puppy development: automated analysis and qualitative behavioral assessmentin repeated open field tests.

Early puppy development is a crucial period that significantly influences a dog's lifelong health, behavior and personality. In this study, the behavioral development of Kangal puppies was investigated through repeated open-field testing, focusing on exploratory behavior, mobility, and responses to novel stimuli. Thirty-three Kangal puppies (20 males and 13 females) from various breeding centers in Sivas Province, Türkiye, were evaluated. The puppies were tested in a controlled open-field environment at 5, 6, and 8 weeks of age. Tests included a novel environment test at 5 weeks and novel object tests at 6 and 8 weeks. Mobility rate, exploration rate, and total distance parameters were measured using automated tracking software (ToxTrac). Qualitative behavioral assessments (QBAs) were performed to evaluate three distinct behavioral and emotional aspects: curiosity, comfort, and fearfulness. The results of these assessments revealed significant increases in curiosity and comfort scores over the testing weeks, with a concomitant decrease in fearfulness. Additionally, tracking data showed increased mobility and decreased exploration rates throughout the testing weeks. Significant correlations were found between curiosity and exploratory behavior, as well as between mobility and comfort scores. Overall, our findings suggest that Kangal puppies exhibit expected behavioral developments in repeated open field testing, with patterns consistent across multiple analyses. These results provide valuable insights into the behavioral development of Kangal puppies and underscore the importance of considering curiosity and other internal motivations in understanding animal behavior.