Figure 4. painless mutant males were capable of distinguishing female from male flies.

(A) Box plots of courtship delay, which represents the latency before males initiated courtship behavior. (B) Total time spent by each individual male on courting decapitated females (left) and decapitated males (right). (C) Average PI of males of indicated genotypes towards females vs. males. Error bars represent SEM. (D–F) are similar as (A–C) except that these experiments were performed under dim red light instead of under white light as in (A–C). P values were determined by the Kruskal-Wallis test, and 43–48 males were examined in each group.