Overview
- Infected Lasius neglectus pupae alter their cuticular hydrocarbon profile only when workers are nearby, indicating active disease signalling rather than a passive byproduct of infection.
- Workers respond by opening the cocoon, biting holes in the pupa, and applying formic acid, disinfecting the pathogen but killing the pupa to protect the colony.
- Transferring the extracted odor from signalling pupae onto healthy brood was sufficient to trigger unpacking and destruction, demonstrating the scent’s causal role.
- Gene-expression data show immune genes are upregulated upon infection regardless of worker presence, but the specific surface-odor change appears only with workers present.
- The signal consists of non-volatile, body-surface hydrocarbons that enable precise, individual targeting; queen pupae were not observed to signal, likely due to stronger immune defenses.