Fig. 2

Sperm competitive ability of New York (EM464) males relative to males from Ohio (PB279) and Germany (SB146). Each graph shows the percentage of offspring fathered by New York males relative to a single competitor. Top panels show the New York male “offense” (P2) after being introduced to a female for 24 h following her being mated with another male for the previous 24 h (i.e., there are no males on the plate on days 2–3). Bottom panels show the opposite or “defense” (P1) response where the New York males were introduced first and then replaced by males from either Ohio or Germany. Panels on the left show results when females from the New York isolate were the mating partners and panels on the right show results when the female matched the non-New York male competitor. Error bars represent standard errors of the binomial frequency estimates