TIL ants that farm aphids influence the aphids’ genes in a similar way that we do with cows. Aphid-farming ants prefer and select for red/green polymorphism.

From the article:

Ant-attended aphids are known to excrete high-quality honeydew when ants are present. Ant attendance has a negative effect on the growth and reproduction of the attended aphids. Therefore, trade-offs should occur between the quality of honeydew and the growth and fecundity of aphid individuals. Thus, if attending ants prefer the morph excreting a high-quality honeydew, such trade-offs and resulting competitive interactions are expected between the color morphs in M. yomogicola. The morph excreting high-quality honeydew is known to have a lower reproductive rate than the other morphs[9,10]. This fact implies that if the attending ants prefer one morph, this morph is expected to excrete high-quality honeydew. Note that any such difference between morphs leads to the exclusion of the inferior morphs. Surprisingly, nearly all colonies consist of both green and red morphs in the field.