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

DOI： 10.1007/s10329-020-00832-3

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Other Link： http://link.springer.com/article/10.1007/s10329-020-00832-3/fulltext.html

Language：English  

Patterns of kinship among individuals in different groups have been rarely examined in animals. Two closest living relatives of humans, bonobos and chimpanzees share many characteristics of social systems including male philopatry, whereas one major difference between the two species is the nature of intergroup relationship. Intergroup relationship is basically antagonistic and males sometimes kill individuals of other groups in chimpanzees, whereas it is much more moderate in bonobos and copulations between individuals of different groups are often observed during intergroup encounters. Such behavioural differences may facilitate more frequent between-group male gene flow and greater between-group differentiation in male kinship in bonobos than in chimpanzees. Here we compared differences between average relatedness among males within groups and that among males of neighbouring groups, and between-group male genetic distance between bonobos and chimpanzees. Contrary to expectation, the differences between average relatedness among males within groups and that among males of neighbouring groups were significantly greater in bonobos than in chimpanzees. There were no significant differences in autosomal and Y-chromosomal between-group male genetic distance between the two species. Our results showed that intergroup male kinship is similarly or more differentiated in bonobos than in chimpanzees.

DOI： 10.1038/s41598-019-57133-z

PubMed

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

DOI： 10.1002/ajpa.23929

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ajpa.23929

Publishing type：Research paper (scientific journal)   Publisher：Kyoto University Library  

DOI： 10.5134/245231

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Language：English  

In many group-living mammals, mothers may increase the reproductive success of their daughters even after they are nutritionally independent and fully grown [1]. However, whether such maternal effects exist for adult sons is largely unknown. Here we show that males have higher paternity success when their mother is living in the group at the time of the offspring's conception in bonobos (N = 39 paternities from 4 groups) but not in chimpanzees (N = 263 paternities from 7 groups). These results are consistent with previous research showing a stronger role of mothers (and females more generally) in bonobo than chimpanzee societies.

DOI： 10.1016/j.cub.2019.03.040

Web of Science

PubMed

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Publishing type：Research paper (scientific journal)   Publisher：Kyoto University Library  

DOI： 10.5134/236291

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Language：English  

Although both bonobos and chimpanzees are male-philopatric species, outcomes of male-male reproductive competition seem to be more closely associated with mating success in chimpanzees. This suggests that the extent of male reproductive skew is lower in bonobos. In addition, between-group male-male reproductive competition is more lethal in chimpanzees. This suggests that between-group differentiation in male kinship is lower in bonobos. We analysed the paternity of 17 offspring in two bonobo groups and estimated the relatedness of individuals among three neighbouring groups by using DNA extracted from non-invasive samples at Wamba, in the Democratic Republic of the Congo. The alpha males sired at least nine of 17 offspring. This supports a previous finding that the male reproductive skew is higher in bonobos than that in chimpanzees. Average relatedness among males within groups was significantly higher than that among males across groups, whereas there was no significant difference among females between within and across groups. These results are consistent with male philopatry, highly skewed reproductive success of males and female dispersal. Higher average relatedness among males within groups suggest that the differences in hostility towards males of different groups between bonobos and chimpanzees may be explained by factors other than kinship.

DOI： 10.1098/rsos.171006

Web of Science

PubMed

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

DOI： 10.1007/s10764-018-0058-2

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Other Link： http://link.springer.com/content/pdf/10.1007/s10764-018-0058-2.pdf

Publishing type：Research paper (scientific journal)   Publisher：Kyoto University Library  

DOI： 10.5134/228896

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PUBLIC LIBRARY SCIENCE  

We report here where the most recent common ancestor (MRCA) of bonobos (Pan paniscus) ranged and how they dispersed throughout their current habitat. Mitochondrial DNA (mtDNA) molecular dating to analyze the time to MRCA (TMRCA) and the major mtDNA haplogroups of wild bonobos were performed using new estimations of divergence time of bonobos from other Pan species to investigate the dispersal routes of bonobos over the forest area of the Congo River's left bank. The TMRCA of bonobos was estimated to be 0.64 or 0.95 million years ago (Ma). Six major haplogroups had very old origins of 0.38 Ma or older. The reconstruction of the ancestral area revealed the mitochondrial ancestor of the bonobo populations ranged in the eastern area of the current bonobos' habitat. The haplogroups may have been formed from either the riparian forests along the Congo River or the center of the southern Congo Basin. Fragmentation of the forest refugia during the cooler periods may have greatly affected the formation of the genetic structure of bonobo populations.

DOI： 10.1371/journal.pone.0174851

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

Group-living animals need to coordinate their activity in order to maintain gregariousness. Although individuals have their own nutritional, social, and reproductive needs, they have to reach consensus to decide where and when to travel. Collective movements are the outcome of one individual's departure, who is then followed by other group members. We investigated departure initiation in a group of bonobos at Wamba, DR Congo, to determine the distribution of leadership among group members. If three or more bonobos started moving more than 30 m, we assigned the individual who moved first as the one who initiated the movement. Two hundred and fifty-four departures were observed. First, we examined whether the frequency of initiation differed according to the following attributes of individuals: sex, age, stage in sexual swelling cycle, dominance, and affiliative relationship. We also examined whether one or more individual(s) initiate departure more or less frequently than expected by chance. A significant interaction between sex and age was found, indicating that the effect of age was greater among females than among males. Individuals who were more central to the grooming network initiated departures more frequently. The three oldest females initiated more often than expected. Old females may be followed because of coalitionary supports they often give to younger females, and of their greater knowledge about ranging area. Leadership in bonobos was not equally shared among group members, and old females were "key individuals" who helped to maintain cohesiveness in their fission-fusion society.

DOI： 10.1007/s00265-017-2277-5

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

The scale of the y-axis of Fig. 1 is incorrect. It should be 0, 0.02, 0.04… instead of 0, 0.2, 0.4… The correct figure is given below.

DOI： 10.1016/j.anbehav.2016.08.017

Scopus

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER JAPAN KK  

Maternal cannibalism, whereby a mother consumes her own offspring, occurs in various animal taxa and is commonly explained by nutritional stress or environmental pressures. It is rare in nonhuman primates and is considered an aberrant behavior only observed under high-stress conditions. It was therefore surprising when, in the first reported case of cannibalism in wild bonobos, a mother consumed part of the dead infant at LuiKotale. Here we report two more cases of maternal cannibalism by wild bonobos at two different study sites, Wamba and Kokolopori. The dead infants' mothers participated in the cannibalism in both cases. At Kokolopori, although the mother did consume part of the carcass, it was held and shared by another dominant female. At Wamba, the mother was a dominant female within the community and was the primary consumer of the carcass. In both cases, cannibalism resembled other meat-eating events, with the dominant female controlling meat consumption. Infanticide was not observed in either case, but its occurrence could not be ruled out. Although rare, the occurrence of maternal cannibalism at three different study sites suggests that this may represent part of the behavioral repertoire of bonobos, rather than an aberrant behavior.

DOI： 10.1007/s10329-016-0582-7

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD  

Patterns of coalitionary aggression among female animals are generally explained by kin selection theory. Frequent female coalitions are almost exclusively observed in female-philopatric species, where females stay in their natal group, and females typically form coalitions with their kin. Bonobos, Pan paniscus, in contrast, are male-philopatric, with females emigrating to new groups at adolescence, but female bonobos frequently form coalitions even though they are generally with nonrelatives. Here we investigated the patterns of female coalitions in a group of wild bonobos at Wamba, Democratic Republic of the Congo, in order to explore alternative mechanisms to kin selection for cooperation among females. We found that all female coalitions (defined as coalitions in which two or more females participated) were formed to attack males, usually after the male(s) behaved aggressively towards one or more females. There was no evidence that female bonobos used proximity, grooming or genito-genital rubbing (GG-rubbing) to develop coalition partnerships, although higher association provided females with more opportunity to form coalitions. Instead of reciprocal agonistic support, we found a unidirectional pattern in which older females supported younger females. Females defeated males more easily when they formed coalitions than when they confronted males alone. Unlike female coalitions in other species that use coalitions to cope with competition among females, our results suggest that coalitions in female bonobos might have evolved as a counterstrategy against male harassment. Females might choose their coalition partners based not on affiliative relationship or reciprocity but on mutualism. In contrast to the hypothesis that affiliative behaviour leads to coalition formation, coalitions might in fact increase gregariousness among females, leading females to develop affiliative interactions that promote tolerance. (C) 2016 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.anbehav.2016.06.021

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：FRONTIERS MEDIA SA  

Lymphocryptovirus (LCV) is one of the major gena in the herpesvirus family and is widely disseminated among primates. LCVs of human and rhesus macaques are shown to be causative agents of a number of malignant diseases including lymphoma and carcinoma. Bonobos (Pan paniscus) are highly endangered and the least studied species of the great apes. Considering the potential pathogenicity of the LCV that might threaten the fate of wild bonobos, population-based epidemiological information in terms of LCV prevalence in different location of Bonobo's habitats will help propose improved conservation strategies for the bonobos. However, such data are not available yet because it is very difficult to collect blood samples in the wild and thus virtually impossible to conduct sero-epidemiological study on the wild ape. In order to overcome this issue, we focused on evaluating anti-LCV IgA in the feces of bonobos, which are available in a non-invasive manner. Preliminary study showed that anti-LCV IgA but not IgG was efficiently and reproducibly detected in the feces of captive chimpanzees. It is noteworthy that the fecal IgA-positive individuals were seropositive for both anti LCV IgG and IgA and that the IgA antibodies in both sera and feces were also detectable by Western blotting assay. These results indicate that the detection of fecal anti-LCV IgA is likely a reliable and feasible for epidemiological surveillance of LCV prevalence in the great apes. We then applied this method and found that 31% of wild bonobos tested were positive for anti LCV IgA antibody in the feces. Notably, the positivity rates varied extensively among their sampled populations. In conclusion, our results in this study demonstrate that LCV is highly disseminated among wild bonobos while the prevalence is remarkably diverse in their population-dependent manner.

DOI： 10.3389/fmicb.2016.01262

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Language：Japanese   Publisher：Primate Society of Japan  

DOI： 10.14907/primate.32.0_35_1

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Language：Japanese   Publisher：Primate Society of Japan  

DOI： 10.14907/primate.32.0_40_1

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Kyoto University Library  

DOI： 10.5134/203112

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Kyoto University Library  

DOI： 10.5134/198894

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BRILL ACADEMIC PUBLISHERS  

One of the most conspicuous behavioural differences among great apes is the paucity of tool use among wild bonobos (Pan paniscus) in comparison to chimpanzees (Pan troglodytes) who are one of the most prolific and skilled tool users in the animal kingdom. This is in spite of the fact that bonobo tool use repertories are as large and diverse as chimpanzees' in captive settings. In this study, we compared tool using behaviours and potential drivers of these behaviours in the Wamba bonobo population located in central Democratic Republic of Congo with the Goualougo chimpanzee population of northern Republic of Congo. The tool use repertoire of wild bonobos was comprised of only 13 behaviours, compared to 42 for chimpanzees. However, the number of tool behaviours observed in each study site was similar between bonobos and chimpanzees, and many types of tool use for social, self-grooming/stimulation, and comfort/protection functions were commonly used by both species. A marked difference is that 25 of 42 tool behaviours exhibited by chimpanzees are performed for feeding, in contrast to a single report of bonobos using a leaf sponge to drink water. We examined whether the differences in tool use repertoires can be explained by the necessity, opportunity, relative profitability, or invention hypotheses. We found that habitat composition and fluctuation of fruit production at these two sites were similar, particularly when compared with variation observed between sites within each species. Thus it was unlikely that the necessity hypothesis explains the lack of tool use for feeding in bonobos. Though further study at Wamba is needed, we did not identify any obvious differences in prey availability that would indicate differences in tool using opportunities between the sites. This study could not test the relative profitability hypothesis, and further research is needed on whether tool use is the most efficient means of calorie or protein intake for wild apes. Bonobos at Wamba formed much larger and stable parties than chimpanzees at Goualougo, which was contrary to the prediction by the invention hypothesis. Another explanation is that differences in tool use behaviour between bonobos and chimpanzees might not be explained by the current ecological or social conditions, but rather by circumstances during the Pleistocene Epoch. The observed species differences might also reflect divergent behavioural predispositions, rather than actual differences in cognitive abilities.

DOI： 10.1163/1568539X-00003226

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：BRILL ACADEMIC PUBLISHERS  

In many social species, the victim often attacks an uninvolved third individual soon after a conflict. This behaviour is called 'redirected aggression' or 'redirection', and its role(s) remain(s) controversial. We observed semi-provisioned free-ranging Japanese macaques at Iwatayama Monkey Park in Arashiyama, Kyoto, Japan, to test three hypotheses concerning the function of redirected aggression: Japanese macaques perform redirection to (1) indirectly retaliate against the aggressor, (2) reduce post-conflict stress, or (3) reduce post-conflict uncertainty. When we observed aggressive interactions, we recorded the behaviour of victims during the subsequent 10 min. Redirection occurred more frequently when the rank of the victim of the initial conflict was high, when the victim was an older monkey, and when conflicts occurred among kin. The results largely supported hypothesis 3. Victims received renewed aggression not only from the initial aggressor but also from bystanders more frequently within 1 min after the initial conflict than in the subsequent 9 min. Victims who performed redirection received less aggression from bystanders. Victims might have been able to avoid renewed aggression because they could change their state from victim to aggressor by performing redirection. This effect of redirection did not differ with the victim's rank. However, the lower the victim's rank, the higher the risk that they would receive retaliation from the target of the redirected aggression or the latter's kin. Thus, redirection caused the same magnitude of benefit and a different magnitude of risk according to the victim's rank. The victim may need to judge his/her own situation when making the decision as to whether to perform redirection.

DOI： 10.1163/1568539X-00003176

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：PUBLIC LIBRARY SCIENCE  

Bonobos (Pan paniscus) inhabit regions south of the Congo River including all areas between its southerly tributaries. To investigate the genetic diversity and evolutionary relationship among bonobo populations, we sequenced mitochondrial DNA from 376 fecal samples collected in seven study populations located within the eastern and western limits of the species' range. In 136 effective samples from different individuals (range: 7-37 per population), we distinguished 54 haplotypes in six clades (A1, A2, B1, B2, C, D), which included a newly identified clade (D). MtDNA haplotypes were regionally clustered; 83 percent of haplotypes were locality-specific. The distribution of haplotypes across populations and the genetic diversity within populations thus showed highly geographical patterns. Using population distance measures, seven populations were categorized in three clusters: the east, central, and west cohorts. Although further elucidation of historical changes in the geological setting is required, the geographical patterns of genetic diversity seem to be shaped by paleoenvironmental changes during the Pleistocene. The present day riverine barriers appeared to have a weak effect on gene flow among populations, except for the Lomami River, which separates the TL2 population from the others. The central cohort preserves a high genetic diversity, and two unique clades of haplotypes were found in the Wamba/Iyondji populations in the central cohort and in the TL2 population in the eastern cohort respectively. This knowledge may contribute to the planning of bonobo conservation.

DOI： 10.1371/journal.pone.0059660

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Language：English   Publisher：SPRINGER TOKYO  

This is the first report to demonstrate that a large mixed-sex party of bonobos travelled a long distance to return to the location of a snare apparently to search for a member that had been caught in it. An adult male was caught in a metallic snare in a swamp forest at Wamba, Luo Scientific Reserve, Democratic Republic of the Congo. After he escaped from the snare by breaking a sapling to which the snare was attached, other members of his party assisted him by unfastening the snare from lianas in which it was caught and licked his wound and tried to remove the snare from his fingers. In the late afternoon, they left him in the place where he was stuck in the liana and travelled to the dry forest where they usually spend the night. The next morning, they travelled back 1.8 km to revisit the location of the injured male. When they confirmed that he was no longer there, they returned to the dry forest to forage. This was unlike the usual ranging patterns of the party, suggesting that the bonobos travelled with the specific intention of searching for this injured individual who had been left behind. The incident described in this report likely occurred because bonobos usually range in a large mixed-sex party and try to maintain group cohesion as much as possible.

DOI： 10.1007/s10329-012-0298-2

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Language：Japanese   Publishing type：Meeting report   Publisher：Primate Society of Japan  

DOI： 10.2354/psj.37.007

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Authorship：Lead author   Language：Japanese   Publishing type：Rapid communication, short report, research note, etc. (scientific journal)   Publisher：Primate Society of Japan  

DOI： 10.2354/psj.37.015

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J-GLOBAL

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Authorship：Lead author   Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (trade magazine, newspaper, online media)  

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Language：Japanese   Publisher：Primate Society of Japan  

DOI： 10.14907/primate.32.0_57_1

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Language：Japanese   Publisher：日本霊長類学会  

【背景】採食生態学は，動物の社会生態を理解する上で基本的かつ非常に重要な分野であり，これまでに多くの研究がなされてきた．近年では，個体追跡による直接行動観察や糞に含まれる未消化の食物断片からの採食内容の同定に加え，糞に含まれる食物 DNAから採食品目を同定する手法も増えてきている．私たちは，2013年 5月～ 6月に実施した京都大学大学院屋久島フィールド実習およびゲノム実習において，次世代シークエンサーを用いて野生ニホンザルの採食品目と腸内細菌叢を網羅的に探索することを試みた．<br>【方法】5月下旬，屋久島・西部林道域に生息する野生ニホンザルを対象に行動観察を実施した．サルの食物を随時記録しながら，計 28個の糞試料を採取した．糞試料から顕微鏡下で食物断片を同定し，更に DNAの抽出を行い，定量結果に基づいて選抜した 10試料について細菌・植物・動物由来 DNAをそれぞれ PCR増幅した．次世代シークエンサーで網羅的にそれらの塩基配列を解読し，配列データベースに対して相同性検索を行って，配列の由来する分類群を決定した．<br>【結果と考察】腸内細菌叢を個体間で比較したところ，門レベルでは大きな違いはなく，属レベルでは個体差が見られたものの，すべて Prevotellaタイプというエンテロタイプ（特定の細菌の比率に基づく腸内細菌叢の分類）に属していた．これは長期的な炭水化物中心の食事と相関するタイプとされている．調査時期におけるニホンザルの主要食物はタブノキやヤマモモの果実であり，糞からもそれらの種子や DNAが検出されたことから，果実食が Prevotellaタイプの腸内細菌叢の形成に寄与していることが示唆された．また，糞からは数多くの種類の節足動物の DNAも検出され，少量であるかもしれないが多様な昆虫類を食べていると考えられた．発表では次世代シークエンサーによって決定された採食品目と腸内細菌叢との関連性について議論する．

DOI： 10.14907/primate.29.0.196.0

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Publisher：Primate Society of Japan  

 攻撃を受けたニホンザルは、その攻撃交渉とは関わりのない個体に対し攻撃を行うことがある（二次攻撃）。二次攻撃は、ニホンザルのみならず、原猿から類人猿まで広く見られる行動であることが知られているが、この行動が行われる理由については、はっきりと明らかにされていない。発表者は、最初に観察された攻撃交渉を「一次攻撃」、その後1分以内に、被攻撃個体が行う他個体への攻撃を「二次攻撃」と定義し、ニホンザルが二次攻撃を行う理由を明らかにすることを目的として研究を行った。<br> 嵐山モンキーパークの餌付けニホンザル集団を対象とし、攻撃交渉をアドリブサンプリング法で観察した。攻撃交渉を観察した際、攻撃個体、被攻撃個体、二次攻撃の有無とその対象を記録した。その後、一次攻撃の被攻撃個体の個体追跡を10分間行い、その間の攻撃交渉を記録した。<br> その結果、被攻撃個体は<br>1. 一次攻撃後1分間は、その後9分間と比べ攻撃を受ける割合が高いこと<br>2. 二次攻撃を行うと、一次攻撃後1分間に攻撃を受ける割合が、二次攻撃を行わなかったときに 比べて大きく下がること<br> が明らかになった。<br> 被攻撃個体が攻撃者に対して見せる劣位の姿勢は、一次攻撃者に対してのみならずその攻撃交渉を見ていた第三者に対しても、被攻撃個体がその時点で劣位な状態にあるという印象を与え、第三者の被攻撃個体に対する攻撃衝動が高まると考えられる。したがって被攻撃個体は、二次攻撃を行うことで自分は弱者ではないと周りの個体にアピールし、追加の攻撃を受けることを避けていると考えられた。

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Language：Japanese   Publisher：日本爬虫両棲類学会  

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Presentation type：Symposium, workshop panel (public)  

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Event date： 2022.5 　 　

Presentation type：Oral presentation (general)  

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Event date： 2022.3 　 　

Presentation type：Symposium, workshop panel (nominated)  

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

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Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

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Language：Japanese   Presentation type：Poster presentation  

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

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Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

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Language：English   Presentation type：Oral presentation (invited, special)   Country：Ethiopia  

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Language：English   Presentation type：Symposium, workshop panel (nominated)  

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Language：English   Presentation type：Symposium, workshop panel (nominated)   Country：Kenya  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：English   Presentation type：Oral presentation (general)   Country：United States  

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Language：English   Presentation type：Symposium, workshop panel (nominated)  

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Language：English   Presentation type：Oral presentation (invited, special)  

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Language：Japanese   Presentation type：Oral presentation (general)  

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Language：Japanese   Presentation type：Poster presentation  

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Language：English   Presentation type：Oral presentation (general)   Country：Australia  

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Language：English   Presentation type：Poster presentation   Country：Japan  

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Language：Japanese   Presentation type：Poster presentation  

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Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

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Language：English   Presentation type：Poster presentation   Country：United Kingdom  

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Language：Japanese   Presentation type：Poster presentation  

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Type：Seminar, workshop

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Type：TV or radio program

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Audience： Junior students,　High school students,　College students,　Graduate students,　Researchesrs,　General

Type：Seminar, workshop

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Type：Science cafe

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Type：Science cafe

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