Juvenile Hormone in Male Courtship

Male-specific brain circuits regulate male mating behavior in the fruit fly Drosophila melanogaster. They are modulated by male-specific components from the circulating fluid (hemolymph). How these hemolymph factors navigate the blood brain barrier (BBB), the tight barrier that protects the brain, is largely unknown. One of the circulating factors is the prominent insect hormone Juvenile Hormone (JH). We hypothesized that it enters the bbb and acts as a signaling molecule in these cells. We knocked down the levels of JH in the bbb by conditionally expressing a JH degrading enzyme in the bbb of adult males and studied the effect on courtship behavior. Our results show a reduction in courtship when JH levels are lowered in the bbb, suggesting a role for the hormone in these cells in the regulation of mating behavior.