抗阿维菌素苜蓿苔螨品系与敏感品系的发育与生殖力

Development,survival,and reproduction of avermectin-resistant Bryobia praetiosa( Acari: Tetranychidae)

探索苜蓿苔螨(Bryobia praetions)抗阿维菌素品系(R)与敏感品系(S)生物适合度变化,为延缓苜蓿苔螨抗性发展及其抗性治理提供依据。在室内26℃条件下,系统观察了苜蓿苔螨抗阿维菌素品系试验种群的发育和生殖力参数。结果表明,抗阿维菌素品系的发育历期和寿命缩短,产卵量下降。抗性品系(R)平均寿命为21.9 d,平均每雌产卵量为28.2粒;敏感品系分别为27.9 d和40.9粒。抗阿维菌素品系的净生殖率(R0=28.17)显著低于敏感品系(R0=45.70)(P<0.05)。抗阿维菌素品系周限增长率(λ)和种群加倍时间(p.b.t)分别为1.159 2和2.978 8,均显著低于敏感品系的周限增长率和种群加倍时间(P<0.05)。对苜蓿苔螨的抗性品系与敏感品系进行比较,抗性品系存在着生殖力的不利性。另外,抗性品系的相对适合度(Rf)约为敏感品系的0.49,也存在着明显的相对适合度缺陷。本研究结论有助于解释苜蓿苔螨抗阿维菌素品系存在生物适合度不利的现象,并为苜蓿苔螨抗性治理提供参考。

We explored biological fitness variability in avermectin-resistant and-susceptible strains of Bryobia praetiosa.Our study offers a theoretical basis to delay resistance development and resistance management of B. praetiosa. Development and reproduction of the avermectin-resistant strain and the susceptible strain of B. praetiosa were evaluated at 26℃. The age-specific life tables of experimental populations of both strains were established. The ecological fitness of the two strains was analyzed by population life-table parameters. Results showed that the development duration of every stage,the average life span,and the number of eggs laid per female of the resistant strain were less than the susceptible strain. The average longevity and eggs laid per female of the resistant strain were 21. 89 days and 28. 17 eggs,respectively,but the average longevity and eggs laid per female of the susceptible strain were 27. 94 days and 40. 91 eggs,respectively. The analysis of the life table showed that there was a difference in the population parameters between the two strains. The net reproductive rate( R0) of the resistant strain( 28. 17) was obviously lower than the R0 of the susceptible strain( 45. 70)( P < 0. 05). The finite rate of increase( λ) and population doubling time( p. d. t.) of the resistant strain were 1. 267 2 and 2. 927 1,respectively. There were significant differences in these parameters between the resistant strain and the susceptible strain( P < 0. 05). The results indicated that the resistant strain was more disadvantageous in developmental and reproductive characteristics than the susceptible strain. In addition,the relative fitness value of the resistant strain was about half that of the susceptible strain,and there was also a significant degree of fitness defect. The results help to explain the fitness disadvantages of the avermectin-resistant strains of B. praetiosa,and provide reference for the management of avermectin-resistant B. praetiosa.