Ever wondered why males in any population are often more likely to get infected, and transmit disease? Well, American biologists say that it may be because of the male sex hormone testosterone.
Daniel Grear, Penn State doctoral student in ecology, has revealed that experiments on mice suggest that high levels of testosterone may be a key factor in spreading disease.
"We know that testosterone makes males more susceptible to disease. We wanted to find out if it impacts their behaviour as well and how that increases their ability to transmit disease," he said.
During the study, Grear and his colleagues investigated the effects of increased testosterone on mice behaviour.
"Our plan was to raise the testosterone levels in wild mice and measure the disease risk they posed to the population," he said while presenting the team's findings at the annual meeting of the Ecological Society of America in Milwaukee, Wisconsin.
Twenty-four male mice trapped at five sites in Huntingdon County, Pennsylvania, were randomly treated with testosterone implants.
Twenty-five other male mice received sham implants, while mice at three separate sites received neither treatment.
Grear has revealed that all sites were trapped twice a week for six weeks before and after treatment.
With the aid of electronic tags, the researchers precisely tracked where the animals were being recaptured.
Such a social network, Grear explained, could help provide a clear picture of how the treated and untreated mice mix on the grids over time.
Tests on recaptured mice indicated that all animals were mixing more when testosterone treated mice were present, said the researchers.
It was also found that all mice at the separate untreated sites made significantly less contacts with other mice during the same time that the testosterone treatment significantly increased contacts.
"These findings suggest that even if some individuals in a population have high levels of testosterone, they can impact the behavior of those around, and drive the transmission of diseases transmitted by close contact such as the respiratory pathogen bordetella," said Grear.
The study had been funded by the National Science Foundation.