著者

Hasegawa Masaru Arai Emi Kojima Wataru Kitamura Wataru Fujita Go Higuchi Hiroyoshi Watanabe Mamoru Nakamura Masahiko

出版者

日本鳥学会

雑誌

Ornithological science (ISSN:13470558)

巻号頁・発行日

vol.9, no.2, pp.161-164, 2010-12

被引用文献数

24 3

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On average, male birds other than social father sire more than 10% of all offspring. Levels of extra-pair paternity below 5% of offspring are rarely found and are now considered worthy of explanation in monogamous birds. We recorded the lowest levels of paternity loss ever reported in a population of Barn Swallows Hirundo rustica. The levels of extra-pair paternity were below 5% of offspring (7/243 in 2005 and 1/53 in 2006). We discuss our results in relation to the density-dependence of extra-pair paternity.

著者

Hasegawa Masaru Arai Emi Watanabe Mamoru Nakamura Masahiko

出版者

日本鳥学会

雑誌

Ornithological science (ISSN:13470558)

巻号頁・発行日

vol.9, no.2, pp.141-148, 2010-12

被引用文献数

44 6

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The maintenance of multiple ornaments by animals can be explained when those multiple ornaments are sexually selected. However, there have been only a few studies of sexual selection on multiple ornaments. We investigated sexual selection on two ornaments, plumage coloration and white spots in the tail, in a population of Barn Swallows Hirundo rustica gutturalis in Japan. There was sexual dimorphism in throat coloration and in the size of the white spots in the tail. Males with a less saturated (colourful) throat and larger white spots in the tail bred earlier than others, indicating a mating advantage for these males. These trends are what would be expected if these ornaments were indeed sexually selected.

著者

Hasegawa Masaru Arai Emi Watanabe Mamoru Nakamura Masahiko

出版者

日本鳥学会

雑誌

Ornithological science (ISSN:13470558)

巻号頁・発行日

vol.7, no.2, pp.117-122, 2008-12

被引用文献数

26 8

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It is necessary to correct plumage color fading when comparing the plumage coloration of birds captured at different times during the breeding season. We proposed two methods for correcting plumage color fading and compared them using the throat feathers of the Barn Swallow (Hirundo rustica gutturalis). One method uses the color shift of feathers on live birds during the same breeding season (the field method). The other method uses longitudinal color measurements of feathers placed on the open ground (the experimental method). This method has an advantage of not capturing the birds twice. The field and experimental methods estimated similar rates of fading of hue and brightness. Saturation was predicted to fade with time in the experimental method, which is unrealistic because there was no effect of time on saturation in live birds. Using the field method, we derived an equation for correcting plumage color fading in Barn Swallows. When assessing changes in plumage color, the field method should be used whenever possible since this method estimates plumage color fading in live birds.

著者

Hasegawa Masaru Arai Emi Watanabe Mamoru Nakamura Masahiko

出版者

Springer

雑誌

Journal of ethology (ISSN:02890771)

巻号頁・発行日

vol.30, no.1, pp.143-150, 2012-01

被引用文献数

26 5

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Female mate choice based on territory quality is difficult to study because territories often contain many resources, which are difficult to quantify. Here, using the barn swallow (Hirundo rustica gutturalis) breeding at an outdoor breeding site in Japan, where each male defends only a small territory containing old nests, we studied whether females choose social mates based on territory quality. Since the territories of this species contain few other resources, territory quality can easily be assessed by quantifying old nests in the territory. We made the following four observations: (1) male swallows displayed old nests in their territories to females; (2) the old nests used for the first clutch were less broken than the other old nests within the same territory; (3) territory quality, defined by the number of old nests weighted by the intactness of each old nest, predicted the productivity of the territory; and (4) males with better territories paired with females earlier, and hence bred earlier, than those with inferior territories. The relationships remained significant even after controlling for male morphological traits. Based on these results, we can infer that female swallows choose their mates based, in part, on territory quality.

著者

斎藤 和志 SAITO Kazushi 中村 雅彦 NAKAMURA Masahiko

出版者

名古屋大学教育学部

雑誌

名古屋大學教育學部紀要 (ISSN:03874796)

巻号頁・発行日

vol.34, pp.97-109, 1987-12-24 (Released:2006-01-06)

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This study attempted to construct the Interpersonal Orientation Scale (ISO) based on the concept proposed by Rubin & Brown (1975). High IOs are interested in and reactive to other people, whereas low IOs are less interested and responsive to others and more concerned with economic features of interpersonal relationships. The scale for Japanese based on Swap & Rubin (1983) was revised to the new scale (ISO-V) which was constructed by eighteen items. Factor analysis of ISO-V yielded three factors : human relation directedness, interpersonal interest and reactivity, and individualistic tendency. This scale had reasonable internal consistency. Correlations between ISO-V and other personality scales indicated expected relations. Then, the validity of IO construct and the usefulness of ISO-V were examined by two experiments. First experiment was aimed to examine the influences of evaluator's IO on attraction toward the self-disclosing other. By this experiment, it was found that high IOs showed greater responsiveness to variations in other's disclosures than did low IOs. Second experiment aimed at exploring the effects of subjects' IO on their opinions about reward allocation and cognition of it. This experiment indicated that high IO individuals liked equality and low IOs took a serious view of own contribution. These results suggested that this scale was useful in understanding behavior in certain social situations.

著者

中村 雅彦 NAKAMURA Masahiko

出版者

名古屋大学教育学部

雑誌

名古屋大學教育學部紀要 (ISSN:03874796)

巻号頁・発行日

vol.32, pp.201-213, 1985-12-20 (Released:2006-01-06)

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Self-disclosure is one of the determinants of interpersonal attraction. The purpose of this paper is to propose a "disclosure-attraction model" which explains the way self-disclosure has effects on the attractiveness of the discloser. The predictions suggested from the model are as follows. (1) If the evaluator attributes the cause of disclosure to the positive intents and/or dispositions of discloser, attraction for the discloser will increase. On the other hand, if he or she attributes it to the negative ones, attraction for the discloser will decrease. (2) The evaluator examines the appropriateness in self-disclosure in terms of social norms and role expectations. Thus, when he or she judges it inappropriate, negative dispositional attributions will produce, resulting in the decrease in attraction. (3) Evaluator's personality variables (e.g., interpersonal orientation, self-monitoring) will make biases on effects of disclosure mentioned above. These predictions were supported clearly by the findings of empirical studies.