1 Current Biology, Volume 19 Supplemental Data Testing for Direct and Indirect Effects of Mate Choice by Manipulating Female Choosiness

The efficacy of female choice treatments. We conducted two distinct sets of experiments to verify that our experimental manipulations of female resistance ability had the intended effects. First, to test for effects on non-random mating by females, we first used phenotypic manipulation to experimentally create low-persistence males by simply ablating one fore tibia and one hind tibia of each male under light CO2 anaesthesia. Since males use their fore legs to grasp females and their hind legs as support during mating attempts, our phenotypic manipulation compromised male ability to maintain an appropriate mating position during premating interactions with females and hence made males less persistent. We note that our manipulation did not noticeably reduce male viability and low-persistence males showed only a moderately depressed mating success (see below). We then introduced two virgin females (both from either of the five female choice treatment groups) to four virgin males (two low-persistence and two normal males) in a 30 mm ø Petri dish, and recorded all matings during 60 minutes (N = 10 such replicates per female choice treatment). All individuals were of 24- 60 hours adult age and low-persistence males, as well as females, were at least 18 hours post-manipulation at the start of the experiments. Ou