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The price of vanity: Mating with showy males may reduce offspring's ability to fight off pathogens
January 11, 2007In many animals, males advertise to potential mates with showy traits, many of which are linked to testosterone levels. However, a new study suggests that, in fish, choosing a flashier mate may cause future generations to be more susceptible to pathogens.
In the January 2007 issue of The American Naturalist, a new study by Judith Mank (Uppsala University, Sweden) finds that mating with males who possess showy traits - such as bright colors or long tails and fins - results in higher testosterone levels in males over many generations. Because male and female testosterone levels are correlated, female choice also results in an increase in female testosterone levels.
Testosterone is an immune suppressor, and increases in testosterone can reduce an animal's ability to fight off diseases. Therefore, a female's choice of a male with exaggerated ornaments may make her daughters and granddaughters less able to resist pathogens, Mank argues.
However, there may be some benefits for the females. For example, females are larger than males in many fish species, perhaps because of the requisite energetic burdens of producing massive amounts of roe, and elevated testosterone increases body size.
Thus, as Mank writes: "The benefits of increased body size to roe production and mate selection may, at least in some cases, counter the immunosuppressive effects of elevated testosterone in females."
University of Chicago Press Journals
However, there may be some benefits for the females. For example, females are larger than males in many fish species, perhaps because of the requisite energetic burdens of producing massive amounts of roe, and elevated testosterone increases body size.
Thus, as Mank writes: "The benefits of increased body size to roe production and mate selection may, at least in some cases, counter the immunosuppressive effects of elevated testosterone in females."
University of Chicago Press Journals
Testosterone Current Events and Testosterone News RSSHeart and bone damage from low vitamin D tied to declines in sex hormones
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Pilot study relates phthalate exposure to less-masculine play by boys
A study of 145 preschool children reports, for the first time, that when the concentrations of two common phthalates in mothers' prenatal urine are elevated their sons are less likely to play with male-typical toys and games, such as trucks and play fighting.
Hormone that affects finger length key to social behavior
The hormones, called androgens, are important in the development of masculine characteristics such as aggression and strength.
Postmenopausal women with higher testosterone levels
Postmenopausal women who have higher testosterone levels may be at greater risk of heart disease, insulin resistance and the metabolic syndrome compared to women with lower testosterone levels.
Fetal study highlights impact of stress on male fertility
Exposure to a combination of excess stress hormones and chemicals while in the womb could affect a man's fertility in later life, a study suggests.
Studies examine how living conditions impact reproductive health
When costs outweigh benefits, successful pregnancies are less likely to occur. Life is all about tradeoffs and recently published research by Virginia J. Vitzthum, a senior scientist at Indiana University's Kinsey Institute for Research in Sex, Gender, and Reproduction, and professor in the IU College of Arts and Sciences' Department of Anthropology, has shown that during periods of intense labor and low food intake, rates of early pregnancy loss can more than double.
BUSM researchers propose a relationship between androgen deficiency and cardiovascular disease
Researchers from Boston University School of Medicine (BUSM) in collaboration with researchers from Lahey Clinic Northshore, Peabody, Mass., believe that androgen deficiency might be the underlying cause for a variety of common clinical conditions, including diabetes, erectile dysfunction, metabolic syndrome and cardiovascular disease (CVD).
Prostate cancer patients on hormone therapy at increased risk for various heart diseases
New research has found that hormone therapy used to treat men with advanced prostate cancer is associated with an increased chance of developing various heart problems. Some choices of therapy appear, however, to be less risky than others.
Obesity increases risk of prostate cancer recurrence for both blacks and whites
A new look at a large database of prostate cancer patients shows that obesity plays no favorites when it comes to increasing the risk of recurrence after surgery: Being way overweight is equally bad for blacks and whites, say researchers at Duke University Medical Center.
Life and death in the living brain
Like clockwork, brain regions in many songbird species expand and shrink seasonally in response to hormones. Now, for the first time, University of Washington neurobiologists have interrupted this natural "annual remodeling" of the brain and have shown that there is a direct link between the death of old neurons and their replacement by newly born ones in a living vertebrate.
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