However, our data raise the possibility that early growth restriction influences the factors involved in partner selection, which may include socialization, sexuality, personality, and emotional responses. When yellow dung flies have lots of sexual partners, their offspring eventually develop larger sexual organs, new research has found. David Hosken of the University of Zurich and colleagues studied the effects of monogamous and polygamous behavior on the evolution of certain sexual characteristics of the flies. The researchers forced flies to be either polygamous or monogamous, and found those that came from polygamous lines developed larger sexual organs, both the males and the females, within 10 generations. The changes apparently occur because the males have to develop traits that help them as they compete to mate, the researchers said.
Females develop their own traits in response.
Genes Offer Clues on Life Span Scientists appear to be homing in on the mechanism that controls life span in a range of creatures. Researchers had previously shown that mutations in a gene involved in regulating the hormone insulin could extend the life span of a roundworm. Now, separate teams of researchers at Brown University and the University College in London, have found that mutations in fruit fly genes involved in regulating insulin extend the life span of that creature. And another team of researchers based at the University of Southern California identified two mutations in insulin-regulating genes that could extend the life span of yeast. The findings suggest that the insulin-regulation system may play an important role in regulating the life span of many creatures, including humans, researchers said.