The central question the team set out to answer is deceptively simple. Insects can learn to associate particular locations with food, danger or home, and models of insect learning have typically treated this as a matter of discrete, reinforced events: a stimulus arrives, a reward follows, and a connection is strengthened. But navigation is different. An ant’s journey is a continuous behavioral process, punctuated only occasionally by meaningful events, while most of what the animal learns along the way is acquired latently, without any explicit reinforcement. Whether insects can keep updating their visual memories throughout this continuous process, rather than only at moments of reward or punishment, has been a stubborn open problem in insect cognition.

To attack the problem, the researchers used a trackball system, a laboratory apparatus in which a tethered ant walks on top of an air-cushioned ball whose rotations are recorded. The crucial feature of this setup is that it prevents visual progress. The ant can see a visual scene, typically the panoramic view surrounding its nest, and it can attempt to walk toward it, but its legs carry it nowhere. From the ant’s perspective, it is straining toward a goal that it can see but never reach. That unnatural impasse turns out to be an extraordinarily revealing probe of how the animal values what it sees.

What the team observed was a steady decline. When ants were placed on the trackball facing a view of their nest, they were initially attracted to it, orienting toward the familiar panorama. But over time, and without any change in motivation or any external reinforcement, that attraction weakened. The nest view simply stopped pulling the ants as strongly as it had before. The researchers interpret this gradual loss of attraction as a form of extinction: the slow fading of a response to a stimulus that, from the animal’s point of view, no longer delivers on what it once promised. Importantly, this decline unfolded as a continuous, time-dependent process rather than being triggered by any discrete event such as the omission of an expected reward.

The details of this decline are what make the study technically striking. First, the memory updates were view-specific: the change applied to the particular visual scene the ants had been exposed to, not to their navigational memories in general. Second, the effect was independent of the ants’ path integrator state, the internal odometer-and-compass system that lets desert and bull ants keep a running tally of their displacement from home. Whether the ants’ path integrator read a short trip or a long one made no difference to how their visual memories were revalued, showing that two of the insect’s major navigation systems, panoramic memory and path integration, operate with considerable independence. Third, and perhaps most importantly, the memory changes persisted for at least 24 hours, indicating that they engage long-term memory processes rather than being fleeting shifts in attention or arousal.

Then came the twist that gives the study its name. When the ants were given a brief exposure to a novel visual scene, one they had not seen before, their attraction to the nest view partially returned. The original memories had not been erased by the extinction-like process; they had been suppressed, and a short burst of novelty was enough to lift that suppression. The team describes this extinction-like process as labile, with the underlying memory preserved beneath it. In classic laboratory paradigms of extinction, from Pavlov’s dogs onward, the loss of a learned response typically depends on the omission of an expected reward, a prediction error that tells the animal its expectations have failed. Here, no such discrete trigger exists. The decline appears to run continuously, driven by time itself, while recovery is what depends on a discrete event: the detection of visual novelty.

The authors propose that these dynamics may be grounded in the architecture of the insect mushroom bodies, the paired brain structures long known to be central to learning, memory and sensory integration in insects. In their proposed model, parallel memory processes within the mushroom bodies interact to produce the observed pattern. One process tracks how long an animal has been exposed to a given view, generating a temporal estimate that gradually drives the extinction-like decline of that view’s attractiveness. A second process performs novelty detection, comparing incoming visual scenes against stored memories, and when a genuinely new scene is detected, it gates the recovery of the suppressed memories. The elegance of this arrangement is that it requires no special machinery beyond circuitry insects are already known to possess: mechanisms for comparing current sensory input with stored templates, and mechanisms for timing exposure.

The ecological logic of such a system is compelling. An ant’s visual world does not hold still. Vegetation grows, shadows shift, light changes with the time of day, and the panorama around the nest looks different from one season to the next. A navigator whose memories were truly static would steadily drift out of register with reality. A system that continuously down-weights views the animal has been staring at without progress, and that snaps memories back into relevance when something genuinely new appears, provides a plausible mechanism for keeping stored snapshots calibrated with the world. In effect, the ants seem to be doing the equivalent of quietly checking whether their map still matches the territory, and revising it on the fly.

The study also carries broader implications for how scientists think about learning in small brains. Current models of insect memory often confine modulations to discrete, reinforced events, precisely because those events are easy to define and easy to model. But the bull ant results suggest that a large share of memory updating happens outside that framework, woven into the ordinary continuous flow of behavior. Latent learning, the acquisition of information without reinforcement, has long been acknowledged in insects, and this work pushes the idea further: not only is information acquired latently, it is also revised latently, with memories gaining and losing value as a function of time and novelty rather than reward. That reframing moves extinction, traditionally a laboratory construct built on reward omission, into the natural behavioral stream of an animal simply trying to get home.

There are practical and conceptual consequences as well. For researchers who use visual memories in ants and other insects as model systems for spatial cognition, the message is that experimental exposures themselves change the animal: every minute an ant spends viewing a scene alters how much that scene will later attract it. For neuroscientists, the proposed split between a time-driven decline process and a novelty-gated recovery process offers a concrete, testable hypothesis about how parallel circuits in the mushroom bodies might implement something functionally resembling extinction and reinstatement without prediction-error signals of the classical kind. And for anyone captivated by the question of what a brain the size of a pinhead can do, the study adds a remarkable entry to the list: these ants appear to run a continuous background revision of their own memories, dimming the familiar when it stops paying off and rekindling it when the world presents something new. The suppressed original memories survive, waiting to be restored, which means an ant’s navigation system may be less like a photograph and more like a living document, annotated and re-annotated with every step of the journey.

Subject of Research: Dynamic updating and extinction of visual route memories in navigating bull ants

Article Title: Dynamic extinction and novelty-triggered recovery of visual route memories in ants

Article References: Dynamic extinction and novelty-triggered recovery of visual route memories in ants. (n.d.). https://doi.org/10.1007/s10071-026-02089-7

Image Credits: AI Generated

DOI: 10.1007/s10071-026-02089-7

Keywords: bull ants, visual navigation, memory extinction, novelty detection, mushroom bodies, long-term memory, latent learning, path integration, insect cognition, trackball, animal cognition, spatial memory

The German Research Foundation, known as the DFG, is supporting the venture with approximately 1.8 million euros over six years. The Emmy Noether Program is one of the most prestigious funding instruments available to early-career researchers in Germany, designed to allow outstanding scientists to build their own independent research groups and qualify for a university teaching career. For Farnworth, the award provides not only financial security but also the freedom to assemble a dedicated team and pursue a long-term scientific vision without the constraints that often accompany more narrowly defined project grants.

Farnworth arrived in Mainz on August 1, 2026, and his group is based at the Institute of Developmental Biology and Neurobiology, where he works in close proximity to the Neural Circuits Lab. The group is additionally affiliated with the Focus Program Translational Neurosciences and the Institute of Pathophysiology, giving it access to a broad network of neuroscientific expertise. The team he is assembling will consist of one postdoctoral researcher, two doctoral researchers, and a part-time technical assistant, a configuration typical of an Emmy Noether group and large enough to combine genetic experimentation, single-cell molecular analysis, and advanced imaging within a single laboratory.

The central question driving the new group is deceptively simple: why are some neural circuits far more evolutionarily flexible than others? Within a single brain, neighboring structures can follow dramatically different evolutionary trajectories. One region may be extensively remodeled across lineages, with new cell types appearing, cell numbers expanding or contracting, and connectivity patterns shifting, while another region remains essentially unchanged over vast stretches of evolutionary time. Understanding what makes a neural circuit conservative or permissive to change would illuminate a fundamental principle of how brains evolve, with implications reaching far beyond insects.

To tackle this question, Farnworth focuses on two well-characterized regions of the insect brain. The first is the mushroom bodies, paired structures best known for their roles in learning and memory, particularly in the context of olfactory association. The second is the central complex, a midline-spanning network of neuropils that serves as the insect’s navigation and orientation hub, integrating sensory information to control walking, turning, and spatial orientation. Over the course of insect evolution, these two regions have diverged sharply in their histories. Mushroom bodies have been extensively remodeled in different groups of insects, reflecting adaptations to widely varying lifestyles, whereas the central complex has remained comparatively conserved, preserving a recognizable ground plan across lineages.

Farnworth’s hypothesis is that the answer to this contrast may lie in development. During the development of an insect, many thousands of nerve cells and millions of connections arise from a comparatively small number of neural stem cells. Specific developmental programs determine which cell types are formed, how many cells of each type are produced, and which connections they establish with one another. We want to understand how these programs change over the course of evolution and how these changes allow neural circuits to adapt to different lifestyles and environmental conditions, Farnworth explains. If the developmental programs governing the mushroom bodies are inherently more modular or more tolerant of variation than those governing the central complex, that could explain why one structure has been free to diversify while the other has been locked in place.

Testing this idea requires a comparative framework, and the group has selected four insect species that together span a wide swath of the insect evolutionary tree: the common fruit fly Drosophila melanogaster, the red flour beetle Tribolium castaneum, the clonal raider ant Ooceraea biroi, and the Indianmeal moth Plodia interpunctella. Each species represents a distinct lineage, and each brings a different lifestyle to the comparison. The fruit fly is the canonical genetic model with a compact brain; the beetle represents holometabolous insects with a different larval development; the clonal raider ant offers a social species in which brain regions involved in learning and communication have adapted to colony life; and the moth adds a lineage with sophisticated olfactory-driven behaviors. By comparing homologous brain structures across these species, the researchers can distinguish features that have been conserved from those that have changed.

Methodologically, the project combines single-cell analyses, genetic tools, and high-resolution imaging. Single-cell approaches allow the team to catalog which cell types are present in each brain region of each species, effectively producing molecular census lists that can be compared across lineages. Genetic methods make it possible to trace the lineages of neural stem cells and to manipulate developmental programs experimentally, revealing how changes in stem cell behavior translate into changes in adult circuitry. High-resolution imaging, meanwhile, documents the anatomy of the resulting circuits, from the positions of cell bodies to the fine structure of the connections they form. Together, these techniques allow the researchers to determine which components of neural circuits have been conserved over evolutionary time and where changes have occurred in cell types, cell numbers, or connectivity.

The work exemplifies an approach often described as neuro-evo-devo, the intersection of neuroscience, evolutionary biology, and developmental biology. Rather than studying a single model organism in isolation, this framework treats development as the mechanism through which evolutionary change is enacted. Mutations do not reshape adult brains directly; they alter developmental programs, and it is these altered programs that produce different cell types, different cell numbers, and different wiring patterns in the next generation. By reading the developmental programs of multiple species and comparing their outputs, researchers can reconstruct how evolutionary transformations in the brain actually happened, and potentially predict which kinds of changes are easy for evolution to make and which are difficult.

For Farnworth, the move to Mainz represents the culmination of a research trajectory that has taken him through several of Europe’s leading institutions. He has been studying the evolution and development of the insect brain since his doctoral research. At the University of Göttingen, he investigated the development of the central complex in fruit flies and red flour beetles, gaining firsthand experience with the comparative approach that now anchors his independent program. Most recently, at the University of Bristol, he studied the evolution of neural circuits in butterflies, extending his comparisons to a lineage in which visual and cognitive adaptations are especially pronounced. JGU provides an excellent research environment for my neuro-evo-devo approach, which seeks to understand brain evolution through its development, Farnworth says. This combination of strong developmental and evolutionary biology is rare. JGU also offers excellent core facilities, particularly in imaging. With the Emmy Noether funding now secured and the group taking shape in Mainz, the coming six years promise to shed new light on one of neuroscience’s deepest questions: how the tiny brains of insects are built, and why evolution has rewritten some parts of their blueprint while leaving others untouched for hundreds of millions of years.

Subject of Research: Evolution and development of neural circuits in the insect brain

Article Title: Evolutionary neurobiologist Max Farnworth joins JGU from Bristol with Emmy Noether Funding

Article References: Evolutionary neurobiologist Max Farnworth joins JGU from Bristol with Emmy Noether Funding. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: neuroscience, evolutionary biology, developmental biology, insect brain, Emmy Noether Program, DFG, mushroom bodies, central complex, neural circuits, Johannes Gutenberg University Mainz, single-cell analysis, neuro-evo-devo