I suspect it's because a higher ratio of females to males wastes less resources on unnecessary males. If there is 1 female to every 1 male, a population of 10 can have 5 sets of offspring every mating season. If there are 4 females to every 1 male, a population of 10 can have 8 sets of offspring every mating season.
NoahMaddyn t1_jc3xbqq wrote
Reply to comment by ubermeisters in A male-killing gene encoded by a symbiotic virus of Drosophila by eniteris
I suspect it's because a higher ratio of females to males wastes less resources on unnecessary males. If there is 1 female to every 1 male, a population of 10 can have 5 sets of offspring every mating season. If there are 4 females to every 1 male, a population of 10 can have 8 sets of offspring every mating season.