抗马拉硫磷淡色库蚊不同基因型的自然内禀增长率及其对抗性演化的影响

INFLUENCE OF THE INTRINSIC RATE OF NATURAL INCREASE FOR DIFFER ENT MALATHION-RESISTANT GENOTYPES ON THE EVOLUTION OF RESISTANCE IN CULEX PIPIENS PALLENS

本文涉及淡色库蚊(Culex pipiens pallens)抗马拉硫磷纯合子(RR)、杂合子(RS)和敏感纯合子(SS)的自然内禀增长率及其对马拉硫磷抗性演化的影响。RR、RS和SS的内禀增长率分别为0.1118、0.1171和0.1339。RR和RS基因型在无杀虫剂时呈现出繁殖不利性,RR和RS的相对适合度分别是SS的0.65和0.68。 影响淡色库蚊对马拉硫磷进化的某些因子在计算机上进行了模拟。模拟的因子包括R等位基因的起始频率(P_o)、所用马拉硫磷的剂量和迁入率(m)。模拟结果表明(I)不用药时R等位基因衰减是由于RR和RS基因型的繁殖不利性;(2)在起始种群N_o=200,P_o=0.1,使用杀死全部SS和RS的剂量(8ppm)处理,使R等位基因为有效隐性,并且m≥0.15时可阻止马拉硫磷抗性的发生。

The intrinsic rate of natural increase for malathion-resistant homozygote (RR), heterozygo-te (RS) and susceptible homozygote (SS), and their influence on the evolution of malathion resistance in Culex pipiens pollens were investigated. The intrinsic rate of natural increase was 0.118 for RR, 0.1171 for RS and 0.1339 for SS. RR and RS genotypes showed reproductive disadvantage in the absence of insecticide. Relative fitness values of RR and RS were 0.65 and 0.68 as compared with SS.Some of factors which influence the evolution of malathion resistance in Culex pipiens pollens were simulated on a computer. The factors simulated included initial frequency of R allele (Pa), dosages of malathion applied and imigration rate (m). The data simulated suggested: (1) that the reversion of frequency of R allele was due to reproductive disadvantage for RR and RS genotypes in the absence of insecticide; and (2) that malathion resistance could be suppressed under the following conditions: initial population size (N0= 200, P0=0.1), making R allele effectively recessive by using a dose of 8 ppm which would kill all SS and RS, and m = 0.15.