sexual reproduction requires both sperm and egg & if something required for a process is not produced then that process is prevented from occurring & the sperm production is prevented in male insects ->  the sexual reproduction process is prevented in the insects  the sexual reproduction process is prevented in the insects & preventing reproduction decreases the rate of reproduction & sexual reproduction is a kind of reproduction ->  the reproduction rate in the insects will decrease  the reproduction rate in the insects will decrease & as the rate of reproduction decreases , the population will decrease -> the population of the insects will decrease