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61.
Juichi Yamagiwa 《Primates; journal of primatology》1985,26(2):105-120
The troop fissions which occurred in a wild population of Japanese monkeys (Macaca fuscata yakui) were observed from 1977 to 1979 on Yakushima Island. The fissions were initiated in the breeding season by non-troop males
who established a consort relation with estrous females. In order to analyze the socio-sexual factors which accelerated the
fissions, the male emigrations and immigrations before and after two successive fissions, and the copulation frequencies,
competition among males and preferences of mating partners in both sexes in the 1977–78 breeding season after the first fission
were examined. The results indicated that three factors (a large number of non-troop males, a shortage of troop males and
the females' choice of mating partners) effectively influenced on the establishment of consort relationships between non-troop
males and estrous females. It is suggested that these factors may exert different effects on the troop disorganization in
relation to troop size. In small-sized troops, a large number of non-troop males and a shortage of troop males may lead to
stronger competition between them, and the females' choice affected by prolonged intimate relations with the dominant TMs
may reduce their priority of access to estrous females. This situation possibly stimulates fission or male emigration in small-sized
troops under the natural conditions on Yakushima Island. In contrast, in large-sized troops under isolated conditions, a surplus
rather than a shortage of troop males may contribute to troop disorganization, as most former studies have suggested. A higher
socionomic sex ratio may decrease the mating activities of subordinate troop males and increase the competition among them.
This situation possibly accelerates the fission of large-sized troops through prolonged interactions between females and subordinate
or peripheral troop males. A lower ratio and the females' choice, however, raise the mating chances of subordinate troop males
and may not promote the fission of large-sized troops under isolated conditions.
This study was financed in part by a Grant-in-Aid for Special Project Research on Biological Aspects of Optimal Strategy and
Social Structure from the Japan Ministry of Education, Science and Culture, and by the Cooperative Research Fund of the Primate
Research Institute, Kyoto University. 相似文献
62.
We compared day-journey length and daily diets of solitary male gorillas in lowland versus highland habitats. Solitary males
in tropical forests of Zaire tend to travel longer distances, to visit more types of vegetation, and to consume more kinds
of food than a solitary male mountain gorilla in the Virunga Volcanoes did. The number of feeding sites per day is larger
and the mean distance between feeding sites is far longer for the former than the latter. These observations may reflect differences
in food breadth and availability between highland and lowland habitats. The herbaceous plants that are eaten by mountain gorillas
are densely and evenly distributed in the higher montane forest of the Virungas, where gorillas need not cover long distances
to search for food. In contrast, herbaceous plants are scarce in primary and ancient secondary forests of lowland habitats,
where gorillas travel long distances and eat various fruits and insects. The patchy and unpredictable distribution of foods
may extend the distances over which gorillas search for food in the lowland habitat. However, solitary males showed a prominent
reduction in day-journey length and changed their choices of food during the nonfruiting season (the long rainy and dry seasons)
in the lowland habitats. This strategy may have developed during the Pleistocene and may have enabled them to enlarge their
ranges to the higher montane forests, where fruits are sparse throughout the year. 相似文献
63.
Information
Acknowledgements 相似文献64.
Juichi Yamagiwa Augustin Kanyunyi Basabose 《American journal of physical anthropology》2009,140(4):739-750
Recent findings on the strong preference of gorillas for fruits and the large dietary overlap between sympatric gorillas and chimpanzees has led to a debate over the folivorous/frugivorous dichotomy and resource partitioning. To add insight to these arguments, we analyze the diets of sympatric gorillas and chimpanzees inhabiting the montane forest of Kahuzi-Biega National Park (DRC) using a new definition of fallback foods (Marshall and Wrangham: Int J Primatol 28 [2007] 1219–1235). We determined the preferred fruits of Kahuzi chimpanzees and gorillas from direct feeding observations and fecal analyses conducted over an 8-year period. Although there was extensive overlap in the preferred fruits of these two species, gorillas tended to consume fewer fruits with prolonged availability while chimpanzees consumed fruits with large seasonal fluctuations. Fig fruit was defined as a preferred food of chimpanzees, although it may also play a role as the staple fallback food. Animal foods, such as honey bees and ants, appear to constitute filler fallback foods of chimpanzees. Tool use allows chimpanzees to obtain such high-quality fallback foods during periods of fruit scarcity. Among filler fallback foods, terrestrial herbs may enable chimpanzees to live in small home ranges in the montane forest, whereas the availability of animal foods may permit them to expand their home range in arid areas. Staple fallback foods including barks enable gorillas to form cohesive groups with similar home range across habitats irrespective of fruit abundance. These differences in fallback strategies seem to have shaped different social features between sympatric gorillas and chimpanzees. Am J Phys Anthropol 140:739–750, 2009. © 2009 Wiley-Liss, Inc. 相似文献
65.
Juichi?YamagiwaEmail author Augustin?Kanyunyi?Basabose Kiswele?Kaleme Takakazu?Yumoto 《International journal of primatology》2005,26(6):1345-1373
We describe the diet of a semihabituated group of Grauer's gorillas (Gorilla beringei graueri) inhabiting the montane forest of Kahuzi-Biega National Park, Democratic Republic of Congo, based on direct observations,
feeding remains in their fresh trails, and fecal samples collected over 9 yr. We examined fruit availability in their habitat;
consumption of fruit, vegetative, and animal food; and daily intake of vegetative plant food using a transect, fruit monitoring
trails, fecal analysis, and tracing of the animal's daily trails between consecutive nest sites. The fruit food repertoire
of Kahuzi gorillas resembles that of western and eastern lowland gorillas inhabiting lowland tropical forests, while their
vegetative food repertoire resembles that of mountain gorillas inhabiting montane forests. Among 236 plant foods (116 species),
leaves, pith, and barks constitute the major parts (70.2%), with fruit making up the minor part (19.7%). About half (53.2%)
of the total fecal samples included fruit remains. The gorillas used leaves, stems and other vegetative plant parts as staples.
Their fruit intake was similar to that reported for mountain gorillas in Bwindi. They ate animal foods, including earthworms,
on rare occasions. Variation in fruit consumption was positively associated with variation in fruit production. The gorillas
ate fig fruits frequently; fig intake is positively correlated with that of other fruits, and figs were not fallback foods.
They relied heavily on bamboo shoots on a seasonal basis; however, no bamboo shoots were available for several years after
a major flowering event. Our results support the argument that variation in gorilla diets mostly reflects variation in vegetational
composition of their habitats. 相似文献
66.
We have found evidence that wild chimpanzees used stout sticks to dig into one end of a decayed fallen trunk from the side
and a long stick with a frayed end to dig into or brush its stump, in the Moukalaba Reserve, Gabon. This type of stick use
by wild chimpanzees has not been recorded in any habitat. This finding should contribute to future studies and discussions
of variations in tool use and cultural processes among wild chimpanzees.
Electronic Publication 相似文献
67.
Kitajiri S Fukumoto K Hata M Sasaki H Katsuno T Nakagawa T Ito J Tsukita S Tsukita S 《The Journal of cell biology》2004,166(4):559-570
Ezrin/radixin/moesin (ERM) proteins cross-link actin filaments to plasma membranes to integrate the function of cortical layers, especially microvilli. We found that in cochlear and vestibular sensory hair cells of adult wild-type mice, radixin was specifically enriched in stereocilia, specially developed giant microvilli, and that radixin-deficient (Rdx(-)(/)(-)) adult mice exhibited deafness but no obvious vestibular dysfunction. Before the age of hearing onset ( approximately 2 wk), in the cochlea and vestibule of Rdx(-)(/)(-) mice, stereocilia developed normally in which ezrin was concentrated. As these Rdx(-)(/)(-) mice grew, ezrin-based cochlear stereocilia progressively degenerated, causing deafness, whereas ezrin-based vestibular stereocilia were maintained normally in adult Rdx(-)(/)(-) mice. Thus, we concluded that radixin is indispensable for the hearing ability in mice through the maintenance of cochlear stereocilia, once developed. In Rdx(-)(/)(-) mice, ezrin appeared to compensate for radixin deficiency in terms of the development of cochlear stereocilia and the development/maintenance of vestibular stereocilia. These findings indicated the existence of complicate functional redundancy in situ among ERM proteins. 相似文献
68.
Mutsuo Shimamura Juichi Yoshitake Tomio Imai 《Bioscience, biotechnology, and biochemistry》2013,77(10):2245-2249
The effect of thiamine on the D-ribulose production from gluconate by a thiamine-requiring Corynebacterium species was investigated. The D-ribulose production by the cells previously grown in a thiamine-deficient medium was higher than that by the cells grown in a thiamine-rich medium and supplementation of the thiamine-deficient cells with thiamine resulted in a significant depression of the D-ribulose production. Gluconokinase and NADP-linked phosphogluconate dehydrogenase were detected in the cell-free extract of this organism. Oxidation and anaerobic dissimilation of D-ribose 5-phosphate by the cell-free extract of the thiamine-deficient cells are reduced and the addition of thiamine pyrophosphate to the extract enhanced the catabolic activities for D-ribose 5-phosphate. These results suggest that the accumulation of D-ribulose by the thiamine-deficient cells is a consequence of a reduction of transketolase activity. 相似文献
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