The steroid hormone testosterone regulates the expression of reproductive behaviors and sexual traits of many animal species. While high levels of testosterone are required for reproductive activities or for the expression of sexual traits, these are often costly, and can lead, for instance, to increased parasite infection. Such costs would also ensure honesty in sexual signals or behavior used by animals for assessing the healthiness of a potential mate.
The mechanisms linking elevated testosterone and increased parasite infection remains little know in wild animals. One possibility is that testosterone modifies behavior and increases exposure to infective parasite larvae. An alternative mechanism is related to the physiological actions of testosterone, which cause increased susceptibility to parasites.
In an article in the August 2005 issue of The American Naturalist, François Mougeot and colleagues test to determine which mechanism was most likely in a wild game bird of the UK, the red grouse. Using a new treatment, which increased testosterone concentration while blocking its direct actions (by blocking testosterone receptors), they show that the mechanism linking testosterone to parasite infection is via increased susceptibility, and that the action of testosterone on host parasite defense was most likely indirect, via cascading effects mediated by other hormones.
Carrie Olivia Adams | EurekAlert!
Diagnoses: When Are Several Opinions Better Than One?
19.07.2016 | Max-Planck-Institut für Bildungsforschung
High in calories and low in nutrients when adolescents share pictures of food online
07.04.2016 | University of Gothenburg
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences