Ant Neuropeptides Link Hunger to Caregiving, Illuminating Parenting Evolution

A study published in *Nature* examined how two ancient neuropeptides—neuropeptide F (NPF) and allatostatin A (AstA)—govern alloparental care in the clonal raider ant *Ooceraea biroi*. Researchers paired individual ants with larvae, automatically recorded hundreds of interactions, and measured neuropeptide levels across the ants’ lifespan. Young workers, which naturally nurse larvae, displayed high NPF and low AstA in the antennal lobe and anterior dorsoposterior protocerebrum. As workers aged, the balance reversed, coinciding with a shift to foraging. Experimental manipulation of either peptide altered behavior, confirming that NPF promotes caregiving while AstA drives foraging. Starvation increased NPF and brood-care activity; feeding produced the opposite effect, linking nutritional state directly to parental behavior.

Ancient Neuropeptides Control Alloparental Behavior in AntsResearchers may have discovered how parenting behavior evolved in ants

The findings support a long-standing hypothesis that evolution repurposes existing neural circuits rather than inventing new ones. Prior mammalian work identified hunger-related neuropeptides as modulators of parenting, but testing this idea has been difficult because common model organisms (fruit flies, roundworms) do not exhibit parental care. Ants, with a brain of roughly 60 000 cells versus ~100 million in mice, provide a simpler platform to trace conserved circuitry.

Researchers may have discovered how parenting behavior evolved in antsAncient Neuropeptides Control Alloparental Behavior in Ants

The work was led by Daniel Kronauer, head of the Laboratory of Social Evolution and Behavior at Rockefeller University, and co-author T. Kay. The team annotated the ant neuropeptidome, identifying 70 distinct neuropeptides, and focused on NPF and AstA because of their known roles in feeding.

Researchers may have discovered how parenting behavior evolved in ants

• NPF: Elevated in young, starved ants; experimentally increasing NPF boosted larval-care interactions.

Ancient Neuropeptides Control Alloparental Behavior in Ants

• AstA: Enriched in older, well-fed ants; enhancing AstA shifted behavior toward foraging.

Researchers may have discovered how parenting behavior evolved in ants

• Age-dependent shift: The natural transition from caregiver to forager mirrors the reciprocal change in peptide expression.

Researchers may have discovered how parenting behavior evolved in ants

• Nutritional modulation: Starvation amplified NPF and reduced AstA, producing a caregiver-like state even in older ants.

Researchers may have discovered how parenting behavior evolved in ants

Because mammals share homologous feeding-related neuropeptide systems, the ant model may help decipher how parental circuits evolve and how they remodel during healthy aging. The authors suggest that insights from *O. biroi* could inform research on human brain aging and neurodegenerative disease, where caregiving capacities also change over the lifespan.

Researchers may have discovered how parenting behavior evolved in ants

Kronauer emphasized that the study exemplifies evolution’s tendency to reuse existing mechanisms, noting that parental behavior “builds on the neural circuitry for feeding.” Kay highlighted the surprising frequency with which similar parenting strategies have arisen across disparate lineages, describing the results as evidence of constrained evolutionary routes. The researchers also stressed that the ant system offers a tractable avenue for mapping the precise neural circuits underlying these neuropeptide effects, a step that could eventually be applied to mammalian models.

Researchers may have discovered how parenting behavior evolved in ants

• “Our work is a prime example of how evolution seldom invents things from scratch,” — Daniel Kronauer, Laboratory of Social Evolution and Behavior, Rockefeller University

Researchers may have discovered how parenting behavior evolved in ants

• “We learned that parental behaviors build on the neural circuitry for feeding, and that makes some sense,” — Daniel Kronauer

Researchers may have discovered how parenting behavior evolved in ants

• “It amazes me that similar parenting behaviors have evolved so many times in so many distinct animal lineages,” — T. Kay

Researchers may have discovered how parenting behavior evolved in ants

• “Our discovery provides a striking demonstration that neuromodulators can produce age-dependent changes in behavioral proclivities in ants, and I suspect that that’s the case in other animals as well, including in humans.” — Daniel Kronauer

Researchers may have discovered how parenting behavior evolved in ants

While the ant data robustly link NPF and AstA to caregiving, direct experimental confirmation of the same mechanisms in mammals remains pending. Future work must determine whether analogous neuropeptide dynamics operate in vertebrate parental circuits.

Researchers may have discovered how parenting behavior evolved in ants