Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Royal Society  

Death-feigning behaviour is a phenomenon in which a prey is rendered motionless due to stimulation or threat from a predator. This anti-predator defence mechanism has been observed across numerous animal taxa and is considered adaptive in nature. However, longer durations of death feigning can result in decreased opportunities for feeding and reproduction, and therefore is often associated with fitness costs as compared to environments without predators. Differences have also been observed in the frequencies and durations of death feigning within populations, and these differences are thought to be influenced by the balance between survival and other fitness costs. Furthermore, this balance is predicted to vary in response to changes in environmental conditions. In this study, we examined the death feigning in 38 populations of the red flour beetle ( Tribolium castaneum ). Our results demonstrate that frequencies and durations of the death feigning in T. castaneum show geographical variations and a latitude cline, indicating that this behaviour is influenced by location as well as latitude. This study is the first to demonstrate the existence of a latitudinal cline in death feigning and suggests that death-feigning behaviour might have evolved in response to environmental factors that vary with latitude.

DOI： 10.1098/rsbl.2023.0028

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Other Link： https://royalsocietypublishing.org/doi/full-xml/10.1098/rsbl.2023.0028

Authorship：Lead author,　Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1111/jeb.14157

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/jeb.14157

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10709-022-00174-6

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Other Link： https://link.springer.com/article/10.1007/s10709-022-00174-6/fulltext.html

Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.18960/seitai.72.2_179

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10164-022-00757-y

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Other Link： https://link.springer.com/article/10.1007/s10164-022-00757-y/fulltext.html

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1007/s10519-022-10108-9

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1111/jeb.14012

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/jeb.14012

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.anbehav.2022.04.010

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1111/eth.13279

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/eth.13279

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1111/eth.13272

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/eth.13272

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/ece3.8533

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ece3.8533

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<title>Abstract</title>Predator avoidance is an important behavior that affects the degree of adaptation of organisms. We compared the DNA variation of one of the predator-avoidance behaviors, the recently extensively studied "death-feigning behavior”, between the long strain bred for feigning death for a long time and the short strain bred for feigning death for a short time. To clarify how the difference in DNA sequences between the long and short strains corresponds to the physiological characteristics of the death-feigning duration at the transcriptome level, we performed comprehensive and comparative analyses of gene variants in <italic>Tribolium castaneum</italic> strains using DNA-resequencing. The duration of death feigning involves many gene pathways, including caffeine metabolism, tyrosine metabolism, tryptophan metabolism, metabolism of xenobiotics by cytochrome P450, longevity regulating pathways, and circadian rhythm. Artificial selection based on the duration of death feigning results in the preservation of variants of genes in these pathways in the long strain. This study suggests that many metabolic pathways and related genes may be involved in the decision-making process of anti-predator animal behavior by forming a network in addition to the tyrosine metabolic system, including dopamine, revealed in previous studies.

DOI： 10.1038/s41598-021-00987-z

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Other Link： https://www.nature.com/articles/s41598-021-00987-z

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<title>Abstract</title>Since the variables inherent to various diseases cannot be controlled directly in humans, behavioral dysfunctions have been examined in model organisms, leading to better understanding their underlying mechanisms. However, because the spatial and temporal scales of animal locomotion vary widely among species, conventional statistical analyses cannot be used to discover knowledge from the locomotion data. We propose a procedure to automatically discover locomotion features shared among animal species by means of domain-adversarial deep neural networks. Our neural network is equipped with a function which explains the meaning of segments of locomotion where the cross-species features are hidden by incorporating an attention mechanism into the neural network, regarded as a black box. It enables us to formulate a human-interpretable rule about the cross-species locomotion feature and validate it using statistical tests. We demonstrate the versatility of this procedure by identifying locomotion features shared across different species with dopamine deficiency, namely humans, mice, and worms, despite their evolutionary differences.

DOI： 10.1038/s41467-021-25636-x

PubMed

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Other Link： https://www.nature.com/articles/s41467-021-25636-x

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10164-021-00713-2

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Other Link： https://link.springer.com/article/10.1007/s10164-021-00713-2/fulltext.html

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Bet-hedging via polyandry (spreading the extinction risk of the female's lineage over multiple males) may explain the evolution of female multiple mating, which is found in a wide range of animal and plant taxa. This hypothesis posits that females can increase their fitness via polyandrous mating when "unsuitable" males (i.e., males causing reproductive failure for various reasons) are frequent in the population and females cannot discriminate such unsuitable mates. Although recent theoretical studies have shown that polyandry can operate as a bet-hedging strategy, empirical tests are scarce. In the present study, we tested the bet-hedging polyandry hypothesis by using the red flour beetle Tribolium castaneum. We compared female reproductive success between monandry and polyandry treatments when females mated with males randomly collected from an experimental population, including 20% irradiated (infertile) males. In addition, we evaluated geometric mean fitness across multiple generations as the index of adaptability of bet-hedging traits. Polyandrous females showed a significantly higher egg hatching rate and higher geometric mean fitness than monandrous females. These results strongly support the bet-hedging polyandry hypothesis.

DOI： 10.1002/ece3.7418

Web of Science

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ece3.7418

Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.aspen.2021.01.012

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

Many species show rhythmicity in activity, from the timing of flowering in plants to that of foraging behavior in animals. The free-running periods and amplitude (sometimes called strength or power) of circadian rhythms are often used as indicators of biological clocks. Many reports have shown that these traits are highly geographically variable, and interestingly, they often show latitudinal or longitudinal clines. In many cases, the higher the latitude is, the longer the free-running circadian period (i.e., period of rhythm) in insects and plants. However, reports of positive correlations between latitude or longitude and circadian rhythm traits, including free-running periods, the power of the rhythm and locomotor activity, are limited to certain taxonomic groups. Therefore, we collected a cosmopolitan stored-product pest species, the red flour beetle <italic>Tribolium castaneum</italic>, in various parts of Japan and examined its rhythm traits, including the power and period of the rhythm, which were calculated from locomotor activity. The analysis revealed that the power was significantly lower for beetles collected in northern areas than southern areas in Japan. However, it is worth noting that the period of circadian rhythm did not show any clines; specifically, it did not vary among the sampling sites, despite the very large sample size (n = 1585). We discuss why these cline trends were observed in <italic>T</italic>. <italic>castaneum</italic>.

DOI： 10.1371/journal.pone.0245115

PubMed

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Brill  

<title>Abstract</title>
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 <italic>Amphibolus venator</italic> (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 <italic>A. venator</italic> via alterations in investment in reproductive traits with age.

DOI： 10.1163/1568539x-bja10060

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Other Link： https://brill.com/downloadpdf/journals/beh/aop/article-10.1163-1568539X-bja10060/article-10.1163-1568539X-bja10060.xml

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<title>Abstract</title>
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.

DOI： 10.1038/s41467-020-19105-0

PubMed

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Other Link： http://www.nature.com/articles/s41467-020-19105-0

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Royal Society  

Tonic immobility and escape are adaptive anti-predator tactics used by many animals. Escape requires movement, whereas tonic immobility does not. If anti-predator tactics relate to weapon size, males with larger weapons may adopt tonic immobility, whereas males with smaller weapons may adopt escape. However, no study has investigated the relationship between weapon size and anti-predator tactics. In this study, we investigated the relationship between male weapon size and tonic immobility in the beetle
<italic>Gnathocerus cornutus</italic>
. The results showed that tonic immobility was more frequent in males with larger weapons. Although most studies of tonic immobility in beetles have focused on the duration, rather than the frequency, tonic immobility duration was not affected by weapon size in
<italic>G</italic>
.
<italic>cornutus</italic>
. Therefore, this study is the first, to our knowledge, to suggest that the male weapon trait affects anti-predator tactics.

DOI： 10.1098/rsbl.2020.0601

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Other Link： https://royalsocietypublishing.org/doi/full-xml/10.1098/rsbl.2020.0601

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10164-020-00680-0

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Other Link： http://link.springer.com/article/10.1007/s10164-020-00680-0/fulltext.html

Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1111/eth.13094

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/eth.13094

Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1111/jeb.13641

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/jeb.13641

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

<title>Abstract</title>
Circadian rhythms, their free-running periods and the power of the rhythms are often used as indicators of biological clocks, and there is evidence that the free-running periods of circadian rhythms are not affected by environmental factors, such as temperature. However, there are few studies of environmental effects on the power of the rhythms, and it is not clear whether temperature compensation is universal. Additionally, genetic variation and phenotypic plasticity in biological clocks are important for understanding the evolution of biological rhythms, but genetic and plastic effects are rarely investigated. Here, we used 18 isofemale lines (genotypes) of Gnatocerus cornutus to assess rhythms of locomotor activity, while also testing for temperature effects. We found that total activity and the power of the circadian rhythm were affected by interactions between sex and genotype or between sex, genotype and temperature. The males tended to be more active and showed greater increases in activity, but this effect varied across both genotypes and temperatures. The period of activity varied only by genotype and was thus independent of temperature. The complicated genotype–sex–environment interactions we recorded stress the importance of investigating circadian activity in more integrated ways.

DOI： 10.1093/biolinnean/blaa016

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Language：English   Publishing type：Research paper (scientific journal)  

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Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<title>Abstract</title>
The molecular basis of death feigning, an antipredator behavior that has received much attention recently, was analyzed. We compared the gene expression profiles of strains with different behaviors, i.e., different durations of death feigning, in the beetle <italic>Tribolium castaneum</italic>. Beetles artificially selected for short (S) and long (L) durations of death feigning for many generations were compared thoroughly by RNA sequencing. We identified 518 differentially expressed genes (DEGs) between the strains. The strains also showed divergence in unexpected gene expression regions. As expected from previous physiological studies, genes associated with the metabolic pathways of tyrosine, a precursor of dopamine, were differentially expressed between the S and L strains; these enzyme-encoding genes were expressed at higher levels in the L strain than in the S strain. We also found that several genes associated with insulin signaling were expressed at higher levels in the S strain than in the L strain. Quantitative real-time PCR analysis showed that the relative expression levels of <italic>Tchpd</italic> (encoding 4-hydroxyphenylpyruvate dioxygenase, <italic>Hpd</italic>) and <italic>Tcnat</italic> (encoding N<italic>-acetyltransferase</italic>, <italic>Nat</italic>) were significantly higher in the L strain than in the S strain, suggesting the influence of these enzymes on the supply of dopamine and duration of death feigning.

DOI： 10.1038/s41598-019-50440-5

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Other Link： http://www.nature.com/articles/s41598-019-50440-5

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

<title>Abstract</title>
Securing matings is a key determinant of fitness, and in many species, males are the sex that engages in mate searching. Searching for mates is often associated with increased mobility. This elevated investment in movement is predicted to trade-off with sperm competitiveness, but few studies have directly tested whether this trade-off occurs. Here, we assessed whether artificial selection on mobility affected sperm competitiveness and mating behavior, and if increased mobility was due to increased leg length in red flour beetles (Tribolium castaneum). We found that, in general, males selected for decreased mobility copulated for longer, stimulated females more during mating, and tended to be better sperm competitors. Surprisingly, they also had longer legs. However, how well males performed in sperm competition depended on females. Males with reduced mobility always copulated for longer than males with high mobility, but this only translated into greater fertilization success in females from control populations and not the selection populations (i.e. treatment females). These results are consistent with a mate-searching/mating-duration trade-off and broadly support a trade-off between mobility and sperm competitiveness.

DOI： 10.1093/beheco/arz110

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Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s13355-019-00643-z

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Other Link： http://link.springer.com/article/10.1007/s13355-019-00643-z/fulltext.html

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Brill  

<title>Abstract</title>
Tonic immobility is an adaptive anti-predator behaviour observed in many species. This anti-predator behaviour is often correlated with a species’ movement motivation, so a relationship between the duration of tonic immobility and morphological traits supporting movement would be expected. Using the red flour beetle, <italic>Tribolium castaneum</italic>, we carried out two-way artificial selection for the duration of tonic immobility over more than 43 generations, establishing populations with longer (L) and shorter (S) tonic immobility durations compared to those of a non-selected control (C) population. Here, we investigated differences in walking motivation and leg length between the selected populations. Walking motivation was significantly higher in beetles from the S population than that in those from the L population. Moreover, S-population beetles of both sexes had significantly longer legs than those from L and C populations. The present results suggest the evolution of longer legs in response to selection pressure for a shorter duration of tonic immobility in <italic>T. castaneum</italic>.

DOI： 10.1163/1568539x-00003579

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Other Link： https://brill.com/downloadpdf/journals/beh/157/1/article-p17_2.xml

Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10164-019-00596-4

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Other Link： http://link.springer.com/article/10.1007/s10164-019-00596-4/fulltext.html

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10519-019-09962-x

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Other Link： http://link.springer.com/article/10.1007/s10519-019-09962-x/fulltext.html

Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1111/eth.12831

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Other Link： http://onlinelibrary.wiley.com/wol1/doi/10.1111/eth.12831/fullpdf

Authorship：Lead author,　Corresponding author   Publishing type：Research paper (international conference proceedings)   Publisher：IEEE  

DOI： 10.1109/percomw.2019.8730647

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Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1111/jeb.13356

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Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<title>Abstract</title>
Divergent lines selected artificially for many generations make it possible to answer two questions: (1) whether genetic variation still exists within the selected population; and (2) whether the selection itself is costly for the selected strain. In previous studies, the red flour beetle <italic>Tribolium castaneum</italic> was divergently selected artificially for duration of death-feigning, and strains selected for longer (L-strain) and shorter (S-strain) durations of death-feigning have been established (Miyatake et al. 2004, 2008). Because the selection experiments have been conducted for more than 27 generations, genetic variation may be eroded. Furthermore, because another previous study reported physiological costs to L-strains, the L-strains selected artificially for longer duration of death-feigning may have suffered more costs than the S-strains. In the present study, therefore, we relaxed the selection pressure after the 27th or 30th generation of S- and L-strains. We also carried out reverse selection during the most recent eight generations of S- and L-strains. The results showed that each strain clearly responded to relaxation of selection and reverse selection, suggesting that (1) additive genetic variation still existed in both strains after long-term selection, and (2) selection for shorter and longer duration of death-feigning was costly. These results suggest that anti-predator behavior is controlled by many loci, and longer or shorter duration of death-feigning is costly in a laboratory without predators.

DOI： 10.1007/s10164-018-0548-x

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Other Link： http://link.springer.com/content/pdf/10.1007/s10164-018-0548-x.pdf

Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10519-017-9847-1

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Other Link： http://link.springer.com/content/pdf/10.1007/s10519-017-9847-1.pdf

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s10164-015-0452-6

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Other Link： http://link.springer.com/article/10.1007/s10164-015-0452-6/fulltext.html

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Public Library of Science (PLoS)  

DOI： 10.1371/journal.pone.0127042

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Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.jinsphys.2012.02.011

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Event date： 2018.3.14 - 2018.3.18

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

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Language：Japanese   Presentation type：Poster presentation  

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Event date： 2016.3.26 - 2016.3.29

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Event date： 2016.3.20 - 2016.3.24

Language：English   Presentation type：Oral presentation (general)  

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Event date： 2015.11.20 - 2015.11.22

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Event date： 2015.3.26 - 2015.3.28

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Event date： 2014.11.1 - 2014.11.3

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Event date： 2014.3.26 - 2014.3.28

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Event date： 2013.11.29 - 2013.12.1

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Event date： 2012.11.23 - 2012.11.25

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