Researchers have identified and confirmed a gene that enables female fruit flies to synchronize with the mating calls of male flies. Interestingly, mosquitoes also possess this gene and share a comparable mating behavior, suggesting that inhibiting this gene could theoretically help control mosquito populations.
Understanding the mating habits of fruit flies may provide insights into curbing the transmission of diseases by mosquitoes.
A recent study by researchers from the University of Iowa uncovered a gene that regulates the antenna movements of female fruit flies, which is crucial for them to perceive the distinctive sounds made by potential male partners. According to the researchers, this gene is found in mosquitoes as well, and silencing it could reduce mating chances, thereby potentially controlling mosquito population growth.
Mosquitoes are notorious for spreading various diseases that pose risks to human health, including West Nile virus, Eastern equine encephalitis, and Zika virus in the United States. Female mosquitoes transmit these diseases by biting animals and humans, drawing blood infected with pathogens that can be passed on during subsequent bites.
“Mosquitoes actually share a very similar mechanism to fruit flies in terms of active tuning, which could have significant implications for preventing the spread of numerous diseases,” explains Daniel Eberl, a biology professor at Iowa and the study’s lead author. “Thus, comprehending how fruit flies and mosquitoes mate and perceive sound could be vital for public health.”
The researchers utilized tiny microphones to capture the sounds produced when a male fruit fly flaps its wings. These vibrations, or air pulses from the wingbeats, are detected by the antennae of female fruit flies, signaling the presence of a potential mate. A female fruit fly’s antenna functions as a sensory organ, interpreting vibrations similarly to how the human ear hears.
Interestingly, not all courting songs are identical.
“A significant insight for us is that the songs sung by male fruit flies vary slightly among closely related species,” Eberl notes. “Each species has distinct intervals between the sounds. This distinction is important because they seek to mate with their own species, and the song facilitates this recognition.”
Biologists have previously recognized that female flies adjust their antennae to frequencies that align with sounds from males of the same species. However, they were unclear about the intricate process of this fine-tuning and its specific location.
The Iowa team investigated the auditory system of Drosophila melanogaster, a well-studied type of fruit fly. They focused on the Johnston’s organ within the antenna, which is responsible for sound detection. Within this organ, they identified a potassium ion channel that powers neurons linked to the hearing of the fly. Further investigation revealed that a gene named Shal acts as a regulatory gate for this ion channel, controlling when external sounds or movements are transformed into electrical signals transmitted between neurons. This process, governed by the Shal gene, appears essential for the fly’s hearing capability.
To confirm the Shal gene’s importance in female antenna tuning and hearing, the researchers deactivated it.
“When the Shal gene is absent, the fly loses the ability to tune into specific frequencies,” says Eli Gregory, an undergraduate majoring in human physiology from Cedar Rapids, who participated in the gene-deactivation experiments. “The female’s antenna struggle to adjust to the frequency, leading to a diminished response to mating calls.”
Mosquitoes utilize a similar approach in their courtship rituals.
Hence, “we could potentially disable that gene or potassium channel, hindering mosquitoes from mating as effectively, which could lead to fewer mosquitoes and subsequently fewer health issues for humans,” Eberl states.
