Females from dioecious species (A: C. nigoni, B: C. remanei) were initially mated overnight to conspecific males, followed by overnight mating of treatment females (white) to heterospecific males from either dioecious (C. nigoni, C. remanei, C. brenneri) or androdioecious (C. briggsae, C. elegans) species; control females (red) did not receive a second mating. Reproductive output was then quantified as the number of progeny produced two days post mating treatment. (A, B) Females often became sterilized upon a subsequent mating with heterospecific males from dioecious species compared to controls: (A) C. nigoni females (C. remanei males U = 385.5, p = 0.001; C. brenneri males U = 206.5, p≤0.001), (B) C. remanei females (C. nigoni males U = 239.5, p≤0.001; C. brenneri males U = 259.5, p≤0.001). However, females were resistant to harm induced by males of androdioecious species: (A) C. nigoni (C. briggsae males U = 409.5, p = 0.020; C. elegans males U = 577.0, p = 0.291), (B) C. remanei (C. briggsae males U = 887.0, p = 0.886; C. elegans males U = 863.0, p = 0.731). (C) C. nigoni females mated to heterospecific C. briggsae males (solid red line) did not incur a statistically significant survival cost relative to conspecific mating (dashed black line; Kaplan-Meier log-rank test: χ2 = 0.203, df = 1, p = 0.652; ns not significant). Asterisks in (A and B) indicate significant difference from controls (Bonferroni correction for multiple tests were applied; corrected α = 0.0125). Boxplot whiskers in (A and B) indicate 1.5× (interquartile range) and dotted horizontal lines indicate median of viable progeny produced by the controls (females mated with conspecifics); sample sizes are shown in parentheses.