The question from a listener was short: what did the hosts think of "the Connectome fruit fly"? On an episode of Moonshots with Peter Diamandis, recorded on September 16, 2026 and published three days later, computer scientist Alexander Wissner-Gross gave a short answer. It mixed a claim about his own company, general enthusiasm and an ethical line he does not want crossed.
Wissner-Gross assumed the question was about what he called "the Google-uploaded fruit fly." He then pointed out his own interest. Eon Systems, "a company that I helped found," had announced what he described as "the first multi-behavior fruit fly upload" months earlier, "actually beating by many months the Google fruit fly upload."
His position is easier to follow once you separate the two projects he grouped under one word. Google's project maps a fly. Eon's project runs a fly-like model in a virtual body. Neither shows what, if anything, it is like to be that fly.
What Google mapped
A connectome is a wiring diagram: a map of which nerve cells, or neurons, connect to which. In an announcement dated September 3, Google described a years-long collaboration with HHMI Janelia, researchers at Cambridge and others. The team mapped the brain and ventral nerve cord of an adult male fruit fly. The ventral nerve cord is roughly the insect's equivalent of a spinal cord. The reconstruction contains more than 166,000 neurons, sorted into 11,691 neuron types.
To build it, researchers imaged very thin slices of tissue, reconstructed the cells by computer and had experts classify them. Because the brain and nerve cord are connected in one map, researchers can trace routes from sensory input toward movement. These include circuits for courtship that differ between males and females. According to Google, the map also supports companion studies of vision, taste and social behavior.
This is anatomy. It shows where the connections run, and scientists use it to study how the nervous system works. The map on its own does not move, eat or respond to anything. Google's page was updated on September 21, after the episode was recorded.
What Eon simulated
Eon's project, described in a technical account dated March 10, makes a different kind of claim. The team did not build the brain model itself. It started from an existing simplified neuron model published by Shiu et al., built from the FlyWire fly connectome resource, and connected it to NeuroMechFly, a previously published simulated fly body running in MuJoCo, a physics engine that calculates how bodies move and collide. Eon describes its system as an integration of these previously published components.
The interesting part is the loop between brain and body. Sensory signals enter the brain model. Selected output signals, like those that would travel from a real brain down to the body, influence how the virtual body moves. That movement then changes what the model senses next. Eon showed the simulated fly feeding and grooming.
Eon's own account lists important simplifications:
- Hand-built connections to the body. The model controls movement through a small set of neural outputs. These feed body controllers that had already been trained by imitation, and many of the links between brain signals and body actions were chosen by hand.
- Limited vision. Activity related to vision did not yet substantially affect behavior, and escape behavior was not built into the body.
- No learning. The model had no learning or plasticity, meaning its connections could not change with experience. Hormonal effects and much of the fly's internal state were also missing.
- Unchecked internal activity. Eon had not yet compared several important features of the model's internal activity against measurements from real flies.
The authors call the work an early integration and a testbed for improving how brain models connect to bodies. So "multi-behavior upload" is Wissner-Gross's term for a system in which a model built from a wiring map produces a few recognizable behaviors in simulation, with considerable human engineering in between.
The dates also need care. Eon's account came out in March and Google's in September. But one project is an anatomical map of a male fly and the other is an embodied simulation. The earlier date does not mean one team beat the other at the same task.
Wissner-Gross's line: no Bitcoin, no Doom
Wissner-Gross said he is "broadly supportive of uploaded fruit flies," adding, "I think we don't upload enough fruit flies." He went further: "we need to upload substantially all of our biosphere."
He then drew a line. "I am not supportive of torturing uploaded non-human animals," he said. He described writing in his newsletter about uploaded fruit flies "being forced to day-trade Bitcoin," and said some were "being forced to play Doom," the classic video game. He opposes both. His condition for support was that uploaded flies be "treated well and humanely or fruit fly-ly." If that holds, he said, "this is terrific and we should do a lot more of it."
The Bitcoin and Doom examples come from his own account. The episode did not say who built those systems or how they worked. The ethical point also stands apart from the technical record. Neither Google's map nor Eon's simulation, as described by the teams, shows that a virtual fly has experiences or can be harmed. Eon's model lacks learning and much of a real fly's internal state.
That leaves three claims that are easy to blur together. A wiring map shows anatomy. A simulation connected to a body shows that some behavior can be reproduced. Whether that simulation has anything like experience is a separate question that neither project addresses. Wissner-Gross's condition speaks to that third question without waiting for an answer: his support for building virtual animals from real nervous systems depends on how those animals are treated.
The exchange ended quickly. Host Peter Diamandis joked that Alex is "the patron saint of agents and food supplies" and turned to co-host Dave Blundin, who went back to an earlier listener question about AI and mathematics.