Overview
- Lasius neglectus pupae that are fatally infected with the fungus Metarhizium brunneum raise levels of two specific surface hydrocarbons.
- Worker ants detect the contact-based cue, remove the pupae from their cocoons, pierce them, and apply formic acid to kill and disinfect before spores form.
- Transferring chemical extracts from signaling pupae onto healthy pupae was sufficient to trigger elimination, confirming a causal link.
- The alarm operates through non-volatile, surface-bound chemistry, keeping responses localized and minimizing mistaken kills.
- Not every infection elicits the signal, as some pupae—such as future queens—can contain pathogens without triggering removal until recovery becomes impossible.