Costs and benefits of variable breeding plumage in the red-backed fairy-wren.
نویسنده
چکیده
The red-backed fairy-wren is a socially monogamous passerine bird which exhibits two distinct types of breeding male, bright males that breed in bright red and black plumage and dull males that breed in dull brown plumage. Most males spend their first potential breeding season in dull plumage and subsequent breeding seasons in bright plumage, but a relatively small proportion of males develop bright plumage in their first breeding season. This study quantifies morphology, behavior, and reproductive success of dull and bright males to assess the adaptive costs and benefits of bright plumage while controlling for age. Older bright males (two years of age or older) attempted to increase their reproductive success via copulations with extrapair females, whereas younger (one-year old) bright males and dull males did not. Thus, older bright males spent less time on their own territories, intruded on neighboring groups with fertile females more frequently, gave more courtship displays, and had larger sperm storage organs than did younger bright males and dull males. Microsatellite analyses of paternity indicate that the red-backed fairy-wren has extremely high levels of sexual promiscuity, and that older bright males had higher within-brood paternity than dull males or younger bright males. Regardless of age, bright males were more attractive to females in controlled mate choice trials than were dull males, and both age classes of bright males obtained higher quality mates earlier in the breeding season than did dull males, when nesting success was higher. In conclusion, although it appears that bright plumage increases access to higher quality mates, age also plays a central role in determining a male's overall reproductive success because of the high levels of sexual promiscuity exhibited by the red-backed fairy-wren.
منابع مشابه
Sexually Selected Male Plumage Color Is Testosterone Dependent in a Tropical Passerine Bird, the Red-Backed Fairy-Wren (Malurus melanocephalus)
BACKGROUND Sexual signals, such as bright plumage coloration in passerine birds, reflect individual quality, and testosterone (T) may play a critical role in maintaining signal honesty. Manipulations of T during molt have yielded mixed effects on passerine plumage color, in most cases delaying molt or leading to production of drab plumage. However, the majority of these studies have been conduc...
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عنوان ژورنال:
- Evolution; international journal of organic evolution
دوره 56 8 شماره
صفحات -
تاریخ انتشار 2002