Impacts of inter-species matings on hermaphrodites.

<p>Hermaphrodites of each selfing species were mated to males of dioecious (A–C) or another androdioecious (D, E) species and reproductive output was quantified as the number of self-progeny produced two days post mating treatment. (A) <i>C. briggsae</i> and (B) <i>C. elegans</i> produced significantly fewer progeny after heterospecific matings to males of all species tested (white) compared to selfing or “no mating” (blue). (C) <i>C. tropicalis</i> also produced fewer progeny after heterospecific matings, but only to a subset of the species tested. (D) A single heterospecific mating event was sufficient to induce progeny loss for <i>C. briggsae</i> hermaphrodites crossed to <i>C. nigoni</i> males (Mann-Whitney U = 37.0, <i>p</i>≤0.001). (E, F) Males from hermaphroditic species also reduced hermaphrodite self-progeny production following heterospecific mating (<i>C. briggsae</i> U = 65.0, <i>p</i> = 0.001; <i>C. elegans</i> U = 178.0, <i>p</i> = 0.008). However, males from hermaphroditic species were less effective at reducing progeny compared to dioecious males (<i>C. briggsae</i> U = 122.0, <i>p</i>≤0.001; <i>C. elegans</i> U = 631.0, <i>p</i>≤0.001). (G) <i>C. briggsae</i> hermaphrodites mated to <i>C. nigoni</i> males (solid blue line) suffer higher mortality than when mated to <i>C. briggsae</i> males (dashed black line; Kaplan-Meier log-rank test: χ² = 5.218, df = 1, <i>p</i> = 0.022). Asterisks in (A–F) indicate significant difference from selfing control (Mann-Whitney U test <i>p</i><0.05; Bonferroni correction applied in (A–C); (A, C) corrected α = 0.007; (B) corrected α = 0.008; <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001915#pbio.1001915.s007" target="_blank">Table S1</a>). In (A–F), boxplot whiskers indicate 1.5× (interquartile range) and dotted horizontal lines indicate median of viable progeny produced by the selfing control for reference. Dagger (†) in (C) indicates that no successful matings occurred between <i>C. portoensis</i> males and <i>C. tropicalis</i> hermaphrodites. Sample sizes are shown in parentheses. Phylogeny in (A–C) adapted from <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1001915#pbio.1001915-Kiontke1" target="_blank">[34]</a>.