A comparative analysis of animal behavior (e.g., male vs. female groups) has been widely used to elucidate behavior specific to one group since pre-Darwinian times. However, big data generated by new ...sensing technologies, e.g., GPS, makes it difficult for them to contrast group differences manually. This study introduces DeepHL, a deep learning-assisted platform for the comparative analysis of animal movement data, i.e., trajectories. This software uses a deep neural network based on an attention mechanism to automatically detect segments in trajectories that are characteristic of one group. It then highlights these segments in visualized trajectories, enabling biologists to focus on these segments, and helps them reveal the underlying meaning of the highlighted segments to facilitate formulating new hypotheses. We tested the platform on a variety of trajectories of worms, insects, mice, bears, and seabirds across a scale from millimeters to hundreds of kilometers, revealing new movement features of these animals.
Investigating the locomotion mechanisms of animals improves our understanding of both their inherent movements and responses to external stimuli. Moreover, identifying the movement patterns of ...animals reveals their foraging search efficiency. The navigational mechanisms of foraging ants have been well studied; they present typical search strategies for pinpointing their goal. However, the detailed movement patterns of ants and the properties of their exploratory behaviors have yet to be fully studied, perhaps because of the inherent difficulty in investigating ants on a restricted flat field (on which they tend to walk along walls and stop moving around corners). Here, we address this problem using a spherical treadmill system (ANTAM), and we use this system to investigate the diffusiveness of Japanese wood ants’ movements. On the treadmill, the ants walked over long distances without any restrictions. We found that the diffusiveness of movements varied across individuals and depended on time. Interestingly, further analysis indicated that the evolution of individual walkers’ travel paths exhibited pink noise, even if individuals apparently produced different types of trajectories. Such complex paths may be related to optimized search strategies since ants produced both small and long paths unpredictably.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Tracking animal movements such as walking is an essential task for understanding how and why animals move in an environment and respond to external stimuli. Different methods that implemented image ...analysis and a data logger such as GPS have been used in laboratory experiments and in field studies, respectively. Recently, animal movement patterns without stimuli have attracted an increasing attention in search for common innate characteristics underlying all of their movements. However, it is difficult to track the movements in a vast and homogeneous environment without stimuli because of space constraints in laboratories or environmental heterogeneity in the field, hindering our understanding of inherent movement patterns. Here, we applied an omnidirectional treadmill mechanism, or a servosphere, as a tool for tracking two-dimensional movements of small animals that can provide both a homogenous environment and a virtual infinite space for walking. To validate the use of our tracking system for assessment of the free-walking behavior, we compared walking patterns of individual pillbugs (Armadillidium vulgare) on the servosphere with that in two types of experimental flat arenas. Our results revealed that the walking patterns on the servosphere showed similar diffusive characteristics to those observed in the large arena simulating an open space, and we demonstrated that our mechanism provides more robust measurements of diffusive properties compared to a small arena with enclosure. Moreover, we showed that anomalous diffusion properties, including Lévy walk, can be detected from the free-walking behavior on our tracking system. Thus, our novel tracking system is useful to measure inherent movement patterns, which will contribute to the studies of movement ecology, ethology, and behavioral sciences.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Complex biological systems resemble a “black box,” as it is a priori unclear how interactions among individuals will affect the collective (group) behavioral performance. Network analysis is a ...suitable method to shed light on these black boxes by studying the collective behavior of highly integrated social organisms such as ants. Individual within the colony have their own personality and task allocation for sustaining the society. Individual-level data are also important for understanding network structure. To obtain individual-level data such as personality and task allocation, individual behavior was assessed using several well-established information processing methods. To detect individual personalities from the position data, trajectory patterns were used. To analyze trajectory patterns, behavioral motif detection was used. The behavioral motif is the minimum unit of the entire trajectory.
Death feigning (or tonic immobility) is an effective antipredator strategy. However, prolonged immobility on the ground increases the risk of being parasitized or eaten by predators, and thus, ...insects must rouse themselves when appropriate stimulation is provided. Very few studies on the effect of stimulus intensity on arousal from death feigning have been conducted. A previous study using
Tribolium castaneum
showed an existing threshold for the intensity of the stimulus that causes arousal from death feigning. Whether there are differences between species in the threshold for arousal is an interesting question. In the present study, we, therefore, compared the effect of stimulus strength on arousal from death feigning in two closely related species, namely,
T. confusum
and
T. freemani
, which are established strains that have been artificially selected for longer duration of death feigning. Also, part of the study was to determine whether there was a positive association between intensity of stimulus needed to rouse and the duration of death feigning. We discuss why there is a difference in the strength of the stimulus needed for arousal from death feigning among
Tribolium
species, for which we included the data for
T. castaneum
from a previous study.
Abstract
Animal behaviours often dependent on age. In many insect species, walking shows an age-dependent decline, and food intake may also be dependent on age. However, few studies have investigated ...the relationship between age and walking or food intake. In the present study, we compared walking traits and food intake among individuals of different ages in the assassin bug Amphibolus venator (Hemiptera, Reduviidae). The present results showed an age-dependent decline in walking, similar to findings in many animal species. On the other hand, food intake showed a positive correlation with age. Therefore, the decline in walking did not lead to a decline in feeding. The positive relationship between food intake and age may be related to the type of predation, sit-and-wait, used by A. venator via alterations in investment in reproductive traits with age.
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Tonic immobility (TI) is an effective anti-predator strategy. However, long immobility status on the ground increases the risk of being eaten by predators, and thus insects must rouse themselves when ...appropriate stimulation is provided. Here, the strength of vibration causing arousal from the state of TI was examined in strains artificially selected for longer duration of TI (L-strains: long sleeper) in a beetle. We provided different strengths of vibration stimuli to the long sleepers in
Tribolium castaneum
. Although immobilized beetles were never awakened by the stimuli from 0.01 to 0.12 mm in amplitude, almost of the beetles were aroused from immobilized status by the stimulus at 0.21 mm. There was a difference in sensitivity of individuals when the stimuli of 0.14 mm and 0.18 mm were provided. F2 individuals were also bred by crossing experiments of the strains selected for shorter and longer duration of TI. The arousal sensitivity to vibration was well separated in the F2 individuals. A positive relationship was observed between the duration of TI and the vibration amplitude, suggesting that immobilized beetles are difficult to arouse from a deep sleep, while light sleepers are easily aroused by even small vibrations. The results indicate a genetic basis for sensitivity to arousal from TI.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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