کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
322937 540290 2007 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Sexually mature and immature yearling male European ground squirrels: A comparison of behavioral and physiological parameters
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی علوم غدد
پیش نمایش صفحه اول مقاله
Sexually mature and immature yearling male European ground squirrels: A comparison of behavioral and physiological parameters
چکیده انگلیسی

Early puberty may increase lifetime reproductive success, but may also entail diverse costs. In male European ground squirrels (Spermophilus citellus), age at sexual maturity varies among individuals. We compared sexually active and inactive yearling males under standardized conditions in outdoor enclosures. Non-reproductive yearling males hibernated significantly longer than mature males and emerged when the mating period had already started. Testosterone concentrations peaked in the precocious males during premating and mating, and were depressed in the non-reproductive individuals throughout the study period. Emergence body mass was similar in both groups, although sexually immature males were significantly heavier at the end of the active season. Additionally, non-reproductive yearlings grew faster than precocious individuals. Male–male aggression peaked during mating and the following 4 weeks. Intense aggressive interactions like chases and fights were mostly initiated by reproductive males and were directed towards mature competitors. Aggressive behavior in immature males was mainly expressed as spatial displacements. Non-agonistic interactions with females were only observed in sexually active males. Concentrations of fecal cortisol metabolites did not differ between the two male groups and were elevated in the second half of the active season. Leucocyte numbers were reduced during mating in mature males, whereas in immature animals, cell numbers did not change significantly. Our results indicate that early puberty in European ground squirrels involves lower growth rates, high intrasexual aggression, lower prehibernatory body mass, and probably worse immunological condition during mating.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Hormones and Behavior - Volume 52, Issue 5, December 2007, Pages 646–652
نویسندگان
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