Behavioural Processes最新文献

Growing evidence reveals notable phenotypic plasticity in cognition among teleost fishes. One compelling example is the positive impact of enriched environments on learning performance. Most studies on this effect have focused on juvenile or later life stages, potentially overlooking the importance of early life plasticity. To address this gap, we investigated whether cognitive plasticity in response to environmental factors emerges during the larval stage in zebrafish. Our findings indicate that larvae exposed to an enriched environment after hatching exhibited enhanced habituation learning performance compared to their counterparts raised in a barren environment. This work underscores the presence of developmental phenotypic plasticity in cognition among teleost fish, extending its influence to the very earliest stages of an individual's life.

Acoustic communication plays a vital role in predator-prey interactions. Although habitat structure has been shown to affect anti-predator tactics, little is known about how animals vary their behaviors in response to predator calls or heterospecific alarm calls in different environments. Here we used sound playbacks to test the responses of Eurasian tree sparrows (Passer montanus) foraging in harvested/unharvested rice paddy and open residential area. In the first experiment, we tested their behavioral responses to dove calls, male common cuckoo (Cuculus canorus) calls, hawk-like calls mimicked by female common cuckoo, sparrowhawk (Accipiter nisus) calls, and human yell calls produced to scare birds (predator signal playbacks). In the second experiment, we tested their behavioral responses to the Japanese tit’s (Parus minor) territorial songs and alarm calls (heterospecific alarm signal playbacks). Results showed that the tree sparrows had less fleeing in unharvested ripe rice paddy than in harvested rice paddy and open residential area. In predator signal playbacks, call type affected the escape behavior of sparrows in unharvested rice paddy and open residential area but not harvested rice paddy. In alarm signal playbacks, tit alarm calls evoked more fleeing than territorial songs in harvested rice paddy and open residential area but not unharvested rice paddy. These results suggest that anthropogenic habitat changes may influence avian anti-predator tactics.

The goal is to understand consequences of anabolic-androgenic steroid (AAS) abuse on cognitive function, using rats as a model. Economic decision making was evaluated in an operant test of effort value discounting, where subjects choose between 2 levers that deliver large and small rewards differing in maximum value and reward contrast. The hypothesis is that chronic high-dose testosterone increases preference for large rewards. Male rats were treated chronically with testosterone (7.5 mg/kg) or vehicle. Initially, all rats preferred the large reward lever when large and small rewards remained fixed at 3 and 1 sugar pellets, respectively. When different reward values were introduced, and with increasing response requirements, testosterone-treated rats made fewer responses for the large reward, and increased omissions. They earned fewer rewards overall. To determine if testosterone impairs memory, rats were tested for recognition memory with the novel object recognition and social transmission of food preference tasks, and for spatial memory with the radial arm maze and Morris water maze. There was not effect of chronic high-dose testosterone on any memory task. These results suggest that testosterone shifts economic decision making towards larger rewards even when they are disadvantageous, but does not alter memory in rats.

In this short communication, we describe chewing behaviour in sows with no apparent edible substrate in their mouth as a potential social behaviour. Chewing in sows during interaction with unfamiliar sows was unexpectedly observed in a study assessing social abilities and damaging behaviours in group-housed dry sows. Such chewing was observed frequently and performed by almost all sows. To our knowledge, this behaviour has not been described previously in a social context in pigs, but rather as an oral stereotypic behaviour related to chronic hunger. We describe the behaviour in its social context and speculate on reasons for its occurrence in that context.

Group-living animals, including penguins, exhibit affiliative behaviors such as grooming (preening) and proximity. Such behaviors in non-primate animals have been less studied than those in primates. Our research focused on 20 identifiable Humboldt penguins in a zoo, analyzing kin relationships and reciprocity in preening and proximity by employing a 5-minute scan sampling method to observe and record individual behavior. Our findings revealed that preening and proximity were more prevalent among mate pairs. However, among non-mate pairs, such behaviors were more commonly observed between siblings and parent-offspring pairs. Notably, the individuals preened on each other simultaneously in all instances. This study highlights the potential influence of kin selection in shaping the affiliative behavior of penguins. Additionally, our findings indicate that penguins gain benefits from mutual preening. This study contributes to our understanding of social behaviors in non-primate species and emphasizes the need for further comparative studies of various animal taxa to elucidate the evolution of sociality.

A previous study demonstrated that rodents on an inclined square platform traveled straight vertically or horizontally and avoided diagonal travel. Through behavior they aligned their head with the horizontal plane, acquiring similar bilateral vestibular cues – a basic requirement for spatial orientation and a salient feature of animals in motion. This behavior had previously been shown to be conspicuous in Tristram's jirds. Here, therefore jirds were challenged by testing their travel behavior on a circular arena inclined at 0°-75°. Our hypothesis was that if, as typical to rodents, the jirds would follow the curved arena wall, they would need to display a compensating mechanism to enable traveling in such a path shape, which involves a tilted frontal head axis and unbalanced bilateral vestibular cues. We found that with the increase in inclination, the jirds remained more in the lower section of the arena (geotaxis). When tested on the steep inclinations, however, their travel away from the arena wall was strictly straight up or down, in contrast to the curved paths that followed the circular arena wall. We suggest that traveling along a circular path while maintaining contact with the wall (thigmotaxis), provided tactile information that compensated for the unbalanced bilateral vestibular cues present when traveling along such curved inclined paths. In the latter case, the frontal plane of the head was in a diagonal posture in relation to gravity, a posture that was avoided when traveling away from the wall.

Barking and other dog vocalizations have acoustic properties related to emotions, physiological reactions, attitudes, or some particular internal states. In the field of intelligent audio analysis, researchers use methods based on signal processing and machine learning to analyze the digitized acoustic signals’ properties and obtain relevant information. The present work describes a method to classify the identity, breed, age, sex, and context associated with each bark. This information can support the decisions of people who regularly interact with animals, such as dog trainers, veterinarians, rescuers, police, people with visual impairment. Our approach uses deep neural networks to generate trained models for each classification task. We worked with 19,643 barks recorded from 113 dogs of different breeds, ages and sexes. Our methodology consists of three stages. First, the pre-processing stage prepares the data and transforms it into the appropriate format for each classification model. Second, the characterization stage evaluates different representation models to identify the most suitable for each task. Third, the classification stage trains each classification model and selects the best hyperparameters. After tuning and training each model, we evaluated its performance. We analyzed the most relevant features extracted from the audio and the most appropriate deep neural network architecture for that feature type. Even if the application of our method is not ready for being used in ethological practice, our evaluation showed an outstanding performance of the proposed method, surpassing previous research results on this topic, providing the basis for further technological development.

Competitive interactions between species is widely prevalent within the animal world. In this manuscript, we attempted to understand feeding competitions between the Amazon sailfin catfish, an invasive species introduced globally, and rohu, a keystone species native to several countries within southeast Asia. We used two different size classes of each species, large-size having total length (TL, from snout tip to caudal fin) of 15–20 cm and fingerling having TL<6 cm, and feeding duration was used as a proxy to understand competition. Our results demonstrated that feeding durations of large-size rohu were either similar or significantly (P<0.05) higher in presence of catfish when compared to trials in presence of conspecifics, indicating that large-size rohu is not a weak competitor. However, feeding durations of fingerling rohu was significantly (P<0.05) reduced in presence of both large-size and fingerling catfish, when compared to trials in presence of conspecifics. Moreover, fingerling rohu also displayed freeze (alarm) behavior in presence of the catfish. Interestingly, presence of rohu had no significant (P>0.05) impact on feeding durations of catfish. Overall, the study demonstrated that invasive catfish may behaviorally outcompete fingerling rohu, thus, threatening the sustenance of a species that is native to several freshwaters around the globe.

Probability and reciprocation have been implicated as key variables for understanding altruism and cooperation. Social discounting, which describes the decline in reward value as the recipient increases in social distance, has provided a framework through which to examine altruistic and cooperative choice. A previous study introduced reciprocal discounting as a way of studying perceived altruism from others (termed reciprocal altruism). But probability discounting has not yet been examined in relation to reciprocal discounting. In order to extend research on reciprocal discounting, the present study evaluated correlations between social, reciprocal, and probability discounting as well as relations between standard social distance (used in social discounting) and reciprocal social distance (the participant’s perceived social distance placement on someone else’s list) among 129 participants. Upon evaluation, the fit of median reciprocal discount rates to the hyperbolic form was replicated. A strong correlation between social and reciprocal discount rates and a moderate correlation between social and probability discount rates were found as well. Additionally, reciprocal and probability discount rates yielded moderate correlations while reciprocal and standard social distance analyses revealed more correspondence between reward values when persons were socially close (i.e., Person 1) or socially distant (i.e., Person 100). This study provides further evidence that reciprocation and probability likely impact altruistic choice while laying groundwork for further investigations into social distance.

The primary goal of the binary model in this study was to understand the convergence pattern of the Pheidole latinoda ants. Forager and scout ants on the hunt for food use path integration. When they find a food source, they leave a trail pheromone to alert other nest mates. Every ant starts following that trail and reinforces it on their way back home. To investigate the ant convergence pattern, binary and ternary bridges of varying lengths are used. Each bridge is built in such a way that one end is connected to a food source whilst the other end is connected to the nest. The food source is surrounded by water-filled islands. The Pheidole latinoda ant's convergence pattern has been observed following the successful installation of a bridge near the ants' nest. This species took between 1 and 3 and 3–4 min to find the shortest possible path. Numerous studies looking for optimal solutions, such as those addressing the challenges of travelling salesmen, routing in communication networks, etc., may use this convergence or path optimization as their new starting point.