Rewired for Romance: Scientists Give Gift-Giving Behavior to Singing Fruit Flies

In a groundbreaking study published in the journal Science, researchers from Japan have successfully transferred a unique courtship behavior from one species of fruit fly to another. By activating a single gene in insulin-producing neurons, the team made Drosophila melanogaster, a species that typically sings “courtship songs,” perform a gift-giving ritual it had never done before.

The study reveals that the reason for this difference lies in the connection between insulin-producing neurons and the courtship control center in the brain. In gift-giving flies (D. subobscura), these cells are connected, while in singing flies (D. melanogaster), they remain disconnected. This discovery highlights that the evolution of novel behaviors does not necessarily require the emergence of new neurons; instead, small-scale genetic rewiring can lead to behavioral diversification and species differentiation.

The researchers inserted DNA into D. subobscura embryos to create flies with heat-activated proteins in specific brain cells. They used heat to activate groups of these cells and compared the brains of flies that did and did not regurgitate food. The study identified 16-18 insulin-producing neurons that make the male-specific protein FruM, clustered in a part of the brain called the pars intercerebralis.

“Our findings indicate that the evolution of novel behaviors does not necessarily require the emergence of new neurons; instead, small-scale genetic rewiring in a few preexisting neurons can lead to behavioral diversification and, ultimately, contribute to species differentiation,” said Dr. Yusuke Hara, co-lead author from the National Institute of Information and Communications Technology (NICT).

This study demonstrates how scientists can trace complex behaviors like nuptial gift-giving back to their genetic roots to understand how evolution creates entirely new strategies that help species survive and reproduce.

The research was conducted with support from KAKENHI Grant-in-Aid for Scientific Research and has been published in the journal Science on August 14, 2025.

The surprising strategy employed by weaver ants has left scientists stunned, as their unique approach to teamwork could potentially transform the field of robotics. A recent study published in Current Biology reveals that individual weaver ants actually increase their contribution to tasks when working in larger groups, defying the long-standing problem of declining performance with team size.

This phenomenon was first observed by French engineer Max Ringelmann in 1913, who found that human teams’ total force increased as more people joined in, but each individual’s contribution decreased. In contrast, weaver ants (Oecophylla smaragdina) have evolved to form super-efficient teams where individuals actually get better at working together as the group gets bigger.

Lead author Madelyne Stewardson from Macquarie University explains that each individual ant almost doubles their pulling force as team size increases. The researchers set up experiments enticing weaver ant colonies to form pulling chains to move an artificial leaf connected to a force meter. They found that the ants split their work into two jobs: some actively pull while others act like anchors to store the pulling force.

The key to this mechanism lies in the “force ratchet” theory developed by co-lead author Dr Daniele Carlesso from the University of Konstanz. Ants at the back of chains stretch out their bodies to resist and store the pulling force, while ants at the front keep actively pulling. This method allows longer chains of ants to have more grip on the ground, better resisting the force of the leaf pulling back.

The discovery has significant implications for robotics, as current robots only output the same force when working in teams as when alone. Dr Chris Reid from Macquarie’s School of Natural Sciences says that programming robots to adopt ant-inspired cooperative strategies could allow teams of autonomous robots to work together more efficiently.

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Ivermectin, a drug traditionally used to treat neglected tropical diseases like onchocerciasis and lymphatic filariasis, has been shown to significantly reduce malaria transmission by killing the mosquitoes that feed on treated individuals. Given the rising resistance to conventional insecticides, ivermectin could offer an effective new approach to tackle malaria transmission, especially in regions where traditional methods have become less effective.

The Unitaid-funded BOHEMIA project, which conducted two Mass Drug Administration (MDA) trials in high-burden malaria regions – Kwale County (Kenya) and Mopeia district (Mozambique) – assessed the safety and efficacy of a single monthly dose of ivermectin (400 mcg/kg) given for three consecutive months at the start of the rainy season in reducing malaria transmission. In Kenya, the intervention targeted children aged 5-15, while in Mozambique it focused on children under five.

The results showed a 26% reduction in new malaria infection incidence among children who received ivermectin compared to those who received albendazole, the control drug used in the study. The trial involved over 20,000 participants and more than 56,000 treatments, demonstrating that ivermectin significantly reduced malaria infection rates — particularly among children living further from cluster borders or in areas where drug distribution was more efficient.

The safety profile of ivermectin was favorable, with no severe drug-related adverse events and only mild, transient side effects already seen with ivermectin in campaigns against neglected tropical diseases.

“We are thrilled with these results,” says Carlos Chaccour, co-principal investigator of the BOHEMIA project and ISGlobal researcher at the time of the study. “Ivermectin has shown great promise in reducing malaria transmission and could complement existing control measures. With continued research, ivermectin MDA could become an effective tool for malaria control and even contribute to elimination efforts,” Chaccour adds.

These results align with the World Health Organization’s (WHO) criteria for new vector control tools. The findings suggest that ivermectin MDA could be a valuable complementary strategy for malaria control, particularly in areas where mosquito resistance to insecticides is a growing concern.

Lessons from the Mozambique trial also highlighted the importance of strong community engagement and close collaboration with local authorities in ensuring acceptance of the ivermectin MDA. The study found an important reduction in the prevalence of skin infestations such as scabies and head lice in the ivermectin group in Mozambique, and the community reported a major reduction in bed bugs in Kenya.

In addition to reducing malaria transmission, ivermectin MDA offers significant collateral benefits. The BOHEMIA team found an important reduction in the prevalence of skin infestations such as scabies and head lice in the ivermectin group in Mozambique, and the community reported a major reduction in bed bugs in Kenya.

“This research has the potential to shape the future of malaria prevention, particularly in endemic areas where existing tools are failing,” concludes Regina Rabinovich, BOHEMIA PI and Director of ISGlobal’s Malaria Elimination Initiative. “With its novel mechanism of action and proven safety profile, ivermectin could offer a new approach using a well-known, safe drug that can add to the effect of other mosquito control tools available today.”