The percentage of males that attempt to mate is higher when they are exposed to females than to hermaphrodites

The male response efficiency assay measures the percentage of males that attempt to mate with the opposite sex. One day before the experiment, NGM plates were spotted with 13 µL of E. coli OP50-1 culture. Before the experiment, 5 males were placed for 10 min in the center of the ~ 5 mm diameter bacterial spot to let them acclimatize. 15 animals of the opposite sex (hermaphrodites or females) were added to the bacterial spot and observed for 4 min. If a male attempted to mate, as determined by the male tail scanning the body of the other sex, the male response was scored with the number 1. In case there was no attempt, the response was scored as 0. The behavior of each male was recorded only once. For each type of mating (male/hermaphrodite or male/female), 5 replicates were performed.