A GENETIC WEB: Interacting species, such as this Gulf fritillary butterfly (Agraulis vanillae) feeding on goldenrod blooms at the edge of a salt marsh on St. Simons Island, Georgia, have an intimate relationship: the genes of one are likely influencing the phenotype of the other.© BEACHCOTTAGEPHOTOGRAPHY/ISTOCKPHOTO.COM
The relationship between an individual’s phenotype and genotype has been fundamental to the genetic analysis of traits and to models of evolutionary change for decades. Of course, scientists have long recognized that phenotype responds to nongenetic factors, such as environmental variation in nutrient availability or the presence of other, competing species. But by assuming that the genetic component of a particular trait is confined to your genes and only yours, scientists overlooked another important input: the genes of your neighbors.
Take field crickets as an example. To identify potential mates, female crickets listen with ears on their forelegs to the males’ songs, produced by the rubbing together of their forewings. Some males emit series of long, trill-like chirps, an advertisement of their fitness that females ...
