A major challenge for the insect pest management is responding to resistance.The spread of resistance 'genes' throughout a population depends upon initital frequencies, dominance, fitness consequences and the mating system of the pest. The latter is often ignored in pest management strategies, which assume that insects mate randomly and disregard the possibility that females exercise some choice in mating partner. There is now widespread evidence that females both actively select mating partners and, in those species in which females mate with more than one male, influence the paternity of their offspring.