Correlations between ultraviolet coloration, overwinter survival and offspring sex ratio in the blue tit
نویسندگان
چکیده
منابع مشابه
Intensity of nest defence is related to offspring sex ratio in the great tit Parus major.
Nest-defence behaviour of passerines is a form of parental investment. Parents are selected, therefore, to vary the intensity of their nest defence with respect to the value of their offspring. Great tit, Parus major, males were tested for their defence response to both a nest predator and playback of a great tit chick distress call. The results from the two trials were similar; males gave more...
متن کاملMetal pollution does not bias offspring sex ratio in great tit (Parus major).
PURPOSE We measured offspring sex ratios in a resident insectivorous passerine bird, the Great tit Parus major, to find out whether metal pollution around a Finnish copper smelter would bias sex ratios in this territorial forest bird species. Besides a direct effect of pollutants, we were interested in possible indirect effects of pollution-related resource limitation, i.e., changes in food qua...
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Background: Offspring sex ratio (OSR) serves as an important social factor, and various other factors are hypothesized to be associated with it, such as maternal diet, time of ovulation and insemination, environmental phenomena, parental age, and infertility treatment. Objectives: This research was performed to assess the association between mothers’ menarche age, first pregnancy age, and sex r...
متن کاملDoes the Mother or Father Determine the Offspring Sex Ratio? Investigating the Relationship between Maternal Digit Ratio and Offspring Sex Ratio
OBJECTIVE In mammals, high parental testosterone levels present around the time of conception are thought to skew offspring sex ratio toward sons. The second to fourth digit ratio (digit ratio) is now widely accepted as a negative correlate of prenatal testosterone. Thus, we investigated the association between digit ratio and offspring sex ratio. METHODS A total of 508 Korean patients (257 m...
متن کاملthe relationship between learners critical thinking ability and their performance in the reading sections of the tofel and ielts test
the study reflected in this thesis aims at finding out relationships between critical thinking (ct), and the reading sections of tofel and ielts tests. the study tries to find any relationships between the ct ability of students and their performance on reading tests of tofel and academic ielts. however, no research has ever been conducted to investigate the relationship between ct and the read...
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ژورنال
عنوان ژورنال: Journal of Evolutionary Biology
سال: 2003
ISSN: 1010-061X,1420-9101
DOI: 10.1046/j.1420-9101.2003.00550.x