- How does evolution turn a harmless bacterial feeder into an active predator? Our new study led by @marianneroca.bsky.social and published in @pnas.org explores how sensory systems were rewired to enable prey detection and predatory behaviour in nematodes. www.pnas.org/doi/10.1073/... 🧵below!
- In our study we compared the predatory nematode Pristionchus pacificus to its close relative Caenorhabditis elegans. While C. elegans feeds on microbes, P. pacificus can actively hunt and kill other worms!
- To understand how this predatory feeding behaviour may have evolved, we examined genes involved in a key sensory modality that we predicted might be involved in detecting prey - mechanosensation.
- To begin, we made mutations in genes predicted to mediate mechanosensation in our predatory nematode. Like C. elegans, several of these function in touch and threat avoidance. Strikingly, one gene was essential not only for touch but also for efficient prey detection. This is a gene called mec-6.Jan 29, 2026 12:30
- Therefore, a gene that once only helped worms feel touch, has taken on a new job in predatory nematodes—helping them find their prey. This revealed a surprising new role for an old sensory gene.
- Importantly, while mechanosensation was important for detecting prey efficiently it was not the only sense these predatory worms were using. We found successful hunting requires the integration of touch and smell together and disrupting both causes stronger defects than disabling either alone.
- At the neural level, both sensory pathways converge in the same IL2 neurons. These neurons form the first point of contact with prey and act as a hub that translates combined sensory input into attack.
- Together, our results show how evolution can repurpose existing genes and sensory circuits for new purposes so systems that were once used for threat avoidance were rewired to support predation. This illustrates how complex behaviours emerge through evolutionary innovations. @mpinb.mpg.de
