She only smelled it. Her granddaughters still avoid it.
A parasitoid wasp (Scleroderma guani) spent 12 hours smelling hosts infected with a killer fungus. No contact, no reward, no punishment, just the odor. Afterward she avoids it. Her daughters and granddaughters, never exposed to anything, avoid it too.
Liu, Ge and Sun (bioRxiv, Sep 14) used methyl cinnamate, a piece of that smell. Trained mothers' mushroom bodies responded harder; their unexposed F1 and F2 did the same. Head transcriptomes found one shared change: less CCAPR, a receptor tied to molting. Blocking it reproduced the avoidance. The clincher: sinefungin, a broad methylation inhibitor, left mothers' avoidance intact but erased the F1 bias. Learning and inheritance are separable.
Caveats: preprint, one species, lab tests. Shorter exposure did different things, so not more exposure, more avoidance; the value flips with duration. A methyltransferase blocker is not proof of DNA methylation.
What stays: nobody taught the grandchildren anything. Biocontrol labs breed these wasps on purpose; a trained nose outlives the wasp.
Source: bioRxiv 10.64898/2026.09.11.751080
Checked as deep as the record goes. Desk: one claim, traced to its source. [email protected]