Study Unlocks Insects’ Secret for Love in the Dark

Male fruit flies lacking the ability to sense female pheromones are left in the dark when it comes to love, according to a new Dartmouth Medial School (DMS) study that could help control harmful insect populations. Published in the Proceedings of the National Academy of Sciences (PNAS), the research shows that mutations in the gene ppk25 disable males flies’ ability to detect female pheromones that regulate key mating behaviors in fruit flies.

“Fruit flies rely on visual and chemical stimuli to mate and we found that flies missing this gene could not chemically sense the pheromones that signal the presence of a potential mate in the dark,” said the study’s lead author, Dr. Claudio Pikielny, assistant professor of Genetics at DMS. “But once we turned the lights on, they were able to initiate courting behavior quite quickly”.

The researchers bred male fruit flies missing the ppk25 gene and placed them in a chamber with female flies in either the light or the dark to test their response to pheromones. In the light, the mutant males engaged in normal mating behaviors, but by using an infrared camera to monitor their behavior in the dark, the researchers found that the mutant males failed to engage in any mating behavior.

“We concentrated our genetic research on fruit flies because they are excellent genetic models and their innate behavior is very interesting,” said Pikielny. The gene ppk25 is a member of a family of sodium channel subunit genes, which are also found in humans and animals. Mutations in some of these genes in humans can cause increased or decreased blood pressure. Studies also suggest that other genes in this family are involved in sensing touch, tasting salt and even learning and memory in humans, according to Pikielny.

The DMS researchers point out that this research may advance the development of methods to control the reproduction rates of fruit flies and other insects. “In addition to their role as carriers of many lethal diseases, insects are agricultural pests that cause hundreds of millions of dollars in damage,” said Pikielny. “There is a lot of interest in figuring out ways to control certain insect populations without using pesticides or other chemicals that could have deleterious effects on humans and other animals.”

The research team, that includes co-authors Heping Lin, Kevin Mann, Elena Starostina, and Ronald Kinser from the DMS department of Genetics, will now set their sights on determining whether ppk25 functions in the neurons that respond to pheromones or in parts of the brain where that signal is processed. This study was supported by a grant from the National Institutes of Health.

Source: Dartmouth Medical School