Quartet mating experiments between flies from the “A” and “S” dietary regimes, generation 30. Barplots representing the number of pairs formed in quartet mating tests between ASG (“A”) and Starch (“S”) dietary selection lines after 30 generations of selection. Panel A shows pairs formed when lines were tested following rearing own their own regime diets. Panels B–E represent flies from each diet regime, crossed to the opposing diet for one generation (high maternal effect), and tested against uncrossed individuals from each regime, as follows: panel B shows A regime flies crossed onto the S diet and tested against S regime flies (A = > S, tested vs S); panel C shows A regime flies crossed to the S diet tested against A regime flies (A = > S, tested vs A); panel D shows S flies crossed to A diet tested against S flies (S = > A tested vs S); panel E shows S flies crossed to A diet tested against A flies (S = > A tested vs A). Panels F–I represent flies from each regime, crossed to the opposing diet for two generations (low maternal effect), and tested against uncrossed individuals from each regime as follows: panel F is A regime flies crossed onto the S diet and tested against S regime flies (A = > S, tested vs S); panel G is A regime flies crossed to the S diet tested against A regime flies (A = > S, tested vs A); panel H is S flies crossed to A diet tested against S flies (S = > A tested vs S); panel I is S flies crossed to A diet tested against A flies (S = > A tested vs A). In each case, dark orange bars (AA) represent homogamic treatment male/treatment female pairs; light orange bars (BA) represent heterogamic nontreatment male/treatment female pairs; light blue bars (AB) represent heterogamic treatment male/nontreatment female pairs; dark blue bars (BB) represent homogamic nontreatment male/nontreatment female pairs. For panel A, AA = homogamic ASG × ASG type matings, BB = homogamic Starch × Starch matings. Data from all three replicate lines are combined.