Influence of experimentally elevated testosterone on nest defence in dark-eyed juncos.

نویسندگان

  • Cawthorn
  • Morris
  • Ketterson
  • Nolan
چکیده

Testosterone affects the allocation of reproductive effort in male birds. Elevated testosterone causes male dark-eyed juncos, Junco hyemalis, to decrease care of dependant offspring, but this generalization is based largely on reduced provisioning rates by males treated with testosterone. Therefore, we used a predator model to explore the relationship between testosterone and nest defence, a more immediate measure of male parental effort. Control males (C-males) were more likely to respond within 10 min to a mount of an eastern chipmunk, Tamias striatus, placed at the nest than were testosterone-treated males (T-males). However, among males that did respond within 10 min, T-males initiated nest defence as fast as C-males and defended the nest with equal intensity. Females initiated nest defence more rapidly and struck the mount more often than their mates, regardless of the male's treatment. Overall, the decreased likelihood of T-males being present for nest defence (perhaps mediated by their large home ranges) may increase predation rates at their nests and represent an important cost of elevated testosterone levels. Copyright 1998 The Association for the Study of Animal Behaviour

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Experimentally-elevated testosterone, female parental care, and reproductive success in a songbird, the Dark-eyed Junco (Junco hyemalis).

In male dark-eyed juncos (Junco hyemalis), experimentally elevated testosterone (T) decreases male parental care and offspring survival, but results in higher overall fitness through greater mating success. To help address the ensuing question of what prevents selection from favoring higher levels of T in male juncos, we manipulated T in female juncos. A previous study demonstrated no effect of...

متن کامل

Effects of testosterone on use of space by male dark-eyed juncos when their mates are fertile

Testosterone is an important determinant of spatial activity in male birds. Using radiotelemetry, male dark-eyed juncos, Junco hyemalis, were followed during the period when their mates were fertile to investigate the relationship between testosterone and behaviours (territoriality, consorting with female) through which males might guard paternity. Males with experimentally elevated testosteron...

متن کامل

Behavioral and physiological responses to experimentally elevated testosterone in female dark-eyed juncos (Junco hyemalis carolinensis).

Testosterone mediates the expression of many fitness-related traits in male vertebrates and is thought to account for numerous sex differences in trait expression. Testosterone is also secreted by females; however, far less is known regarding its effects on female physiology and behavior. Using a bird species in which the effects of testosterone on males are well characterized, the dark-eyed ju...

متن کامل

Testosterone and innate immune function inversely covary in a wild population of breeding Dark-Eyed Juncos

1. Innate immunity refers to the non-specific components of the primary immune response, which act broadly to destroy pathogens. Effective innate immune responses may save an individual the energetic costs associated with activating subsequent specific immune responses. 2. Testosterone can suppress immune function in vitro and in vivo . Most studies examining testosterone’s effects on immunity ...

متن کامل

Effects of experimentally elevated testosterone on plasma corticosterone and corticosteroid-binding globulin in dark-eyed juncos (Junco hyemalis).

An earlier study of free-living male dark-eyed juncos found an increase in plasma corticosterone (B) in response to experimental elevation of plasma testosterone (T) (E. D. Ketterson et al., 1991, Horm. Behav. 25, 489-503). To investigate whether the increase was caused by enhanced secretion of corticosterone or by a slower clearance rate, or both, we exposed 52 captive yearling male dark-eyed ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Animal behaviour

دوره 56 3  شماره 

صفحات  -

تاریخ انتشار 1998