Velvety tree ant extract is a chemotaxis repellent for C. elegans

Ants use a range of compounds for interspecies interactions, but the neurogenetic mechanisms mediating these interactions are unclear. Here, we used chemotaxis assays with the nematode Caenorhabditis elegans to test if ant compounds can be detected by the worm nervous system and which chemosensory neurons are required for detection. We found that C. elegans avoid the extracts of velvety tree ants ( Liometopum occidentale ), and this response requires osm-9 and tax-4 positive neurons. These experiments were conducted by undergraduate students in an upper-division laboratory course, demonstrating how simple behavior assays conducted in a classroom setting can provide practical research experiences and new insights into interspecies interactions.