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

Shimizu Kaoruko Hasegawa Masaru Makita Hironi Nasuhara Yasuyuki Konno Satoshi Nishimura Masaharu

出版者

Elsevier

雑誌

Respiratory Medicine (ISSN:09546111)

巻号頁・発行日

vol.105, no.9, pp.1275-1283, 2011-09

被引用文献数

36

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Background: Few studies have directly compared airway remodelling assessed by computed tomography (CT) between asthma and chronic obstructive pulmonary disease (COPD). The present study was conducted to determine whether there are any differences between the two diseases with similar levels of airflow limitation under clinically stable conditions. Methods: Subjects included older male asthmatic patients (n = 19) showing FEV1/FVC <70% with smoking history less than 5-pack/year. Age- and sex-matched COPD patients (n = 28) who demonstrated similar airflow limitation as asthmatic patients and age-matched healthy non-smokers (n = 13) were recruited. Using proprietary software, eight airways were selected in the right lung, and wall area percent (WA%) and airway luminal area (Ai) were measured at the mid-portion of the 3rd to 6th generation of each airway. For comparison, the average of eight measurements per generation was recorded. Results: FEV1% predicted and FEV1/FVC was similar between asthma and COPD (82.3 ± 3.3% vs. 77.6 ± 1.8% and 57.7 ± 1.6% vs. 57.9 ± 1.4%). At any generation, WA% was larger and Ai was smaller in asthma, both followed by COPD and then controls. Significant differences were observed between asthma and controls in WA% of the 3rd to 5th generation and Ai of any generation airway, while no differences were seen between COPD and controls. There were significant differences in Ai of any generation between asthma and COPD. Conclusions: Airway remodelling assessed by CT is more prominent in asthma compared with age- and sex-matched COPD subjects in the 3rd- to 6th-generation airways when airflow limitations were similar under stable clinical conditions.