Figure 4.

Late-Stage Secretions Induce Predatory Morph in Juveniles

Highly St strain RSC017 juveniles were exposed to 24- and 72-hr supernatants of its own strain, and to the 24- and 72-hr supernatants of the highly Eu strain RS2333. Mouth form was phenotyped 3 days later. Worms exposed to 24-hr secretions remained highly St, whereas worms exposed to 72-hr secretions had a small but significant increase in Eu morphs (p < 0.05, Fisher's exact test). Supernatants from the double mutant daf-22.1/2, which has deficient ascaroside pheromone production (Golden and Riddle, 1985, Markov et al., 2016), did not elicit increases in Eu from either 24- or 72-hr supernatants. Worms exposed to the S-media control also remained highly St. n = 4 independent biological replicates for RS2333 and daf-22.1/2 secretions, and n = 2 independent biological replicates for RSC017 secretions, with an average count of 55 animals per replicate. For display, total Eu and St counts are presented as percentages (*** p < 0.001, **p < 0.01).