Female red squirrels fit Williams’ hypothesis of increasing reproductive effort with increasing age
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چکیده
منابع مشابه
Face Growth Modeling with Increasing Age in Child and Adolescents
Purpose: The purpose of this study is to present a cranifacial growth model using anthropometry based on changes observed in the human face. Materials and Methods: This cross sectional analytical study was conducted randomly on 45 pepole, with normal face patterns.Facial and cranial ratios were measured and compared. Data was analyzed by SPSS software. The regression line and the growth coeffic...
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Reproductive effort in female ungulates originates from gestation and lactation and has been studied extensively; however, no comparable studies of reproductive effort in males (due to fighting for access to mates) have, to our knowledge, previously been reported. Here, we report on weight loss of male red deer during the annual mating season--a direct measure of male reproductive effort (or so...
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In order to evaluate potential reproductive costs associated with parasitism, we experimentally removed ectoparasites from reproductive female North American red squirrels (Tamiasciurus hudsonicus). Body mass and overwinter survival of mothers, days to juvenile emergence, juvenile survival from birth to emergence, and body mass of juveniles at emergence were all compared to those of untreated (...
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The distinctive features of reproduction in squirrels are the lack of allometric influences on the duration of reproductive investment; the strong allometric influences on offspring mass; and a trade-off between number and size of young, suggesting an important developmental component to reproduction. Lengths of gestation and lactation do not vary with body size but neonatal and weaning mass do...
متن کاملPrevious Experience and Reproductive Investment of Female Columbian Ground Squirrels
Reproductive success of females in iteroparous species usually increases early in life, then remains constant or declines. The restraint hypothesis suggests that primiparous females limit their 1st reproduction in order to avoid future costs to survival, reproduction, or both, whereas constraint indicates that primiparous females are limited in their 1st reproductive attempt either because they...
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ژورنال
عنوان ژورنال: Journal of Animal Ecology
سال: 2007
ISSN: 0021-8790,1365-2656
DOI: 10.1111/j.1365-2656.2007.01301.x