a, C. elegans male mating steps. Dashed lines indicate the transport of sperm. b, Number of hermaphrodites contacted by a male before mating initiation. c, d, Turning (c) and vulva location (d) efficiency of males during mating. e, The efficiency of sperm transfer. For b–e, the numbers of tested males are shown beneath the bars. f, g, Age-dependent changes in pharyngeal pumping rate (f) and locomotion speed (g) in N2, rgba-1, npr-28, and rgba-1;npr-28 mutant worms. The numbers of independent experiments are indicated in parentheses. h, Lifespan curves of N2, rgba-1, npr-28, and rgba-1;npr-28 mutant worms. The numbers of tested hermaphrodites are indicated in parentheses. Data shown in b, d, f and g are mean ± s.e.m., and in c, e, and h represent the sum of animals in three (c, e) or four (h) independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001 (b, d, f, and g, ANOVA with Dunnett’s test; c, e, Fisher’s exact test; h, two-sided log-rank test).