Figure 2.

Conflicts of interests between focal males and females in relation to breeding system. Symbols for extrapair males and their social mates in solid black. Red bars join individuals that are in conflict over the occurrence of the extrapair matings, whereas blue bars join individuals that share the same optimal level (zero for male-driven) or extrapair mating; thin black lines indicate no particular costs or benefits. All cases shown involve female-driven EPP, in which the female benefits from the extrapair mating. Photos show one example species of each mating system: (A) Tree swallow (Tachycineta bicolor), (B) purple martin (Progne subis), (C) red-winged blackbird (Agelaius phoeniceus), (D) Smith’s longspur (Calcarius pictus), (E) red phalarope, and (F) splendid fairywren (Malurus splendens). (All photos courtesy of B. Lyon, except Smith’s longspur, which is provided by Ian Davies.)