单宁酸对淡色库蚊抗氰戊菊酯品系和敏感品系幼虫生长发育的影响

Effects of tannic acid on the development of larvae of the fenvalerate-resistant and susceptible strains of Culex pipiens pallens (Diptera: Culicidae)

单宁酸是一种植物次生代谢物,为探索其用于蚊幼虫防治的可能性,在室内测定了其对淡色库蚊Culex pipiens pallens抗氰戊菊酯品系和敏感品系1～4龄幼虫的毒性,并观察了其对存活幼虫生长发育的影响。结果表明,淡色库蚊敏感品系幼虫对单宁酸的敏感性比抗氰戊菊酯品系的要高,1～4龄幼虫分别高6.4、4.9、4.7和2.0倍。4个龄期幼虫中,无论是敏感品系还是抗氰戊菊酯品系,均是1龄幼虫对单宁酸的敏感性最高,3龄幼虫最低。在1000mg/L单宁酸持续作用下,敏感品系和抗氰戊菊酯品系各龄幼虫的存活率,均随处理时间延长而降低。与对照相比,饲养在100mg/L～500mg/L单宁酸溶液中的存活幼虫发育历期延长,敏感品系和抗氰戊菊酯品系发育历期分别延长了34.5～38.3h和59.2～93.4h。其中,125mg/L浓度处理的敏感品系1～4龄幼虫,其发育历期与对照的差异达到了显著水平(P<0.05);抗性品系则在250mg/L作用下也达到了差异显著水平(P<0.05)。但100～250mg/L单宁酸处理淡色库蚊抗氰戊菊酯品系和敏感品系1龄幼虫,对其存活幼虫的化蛹率、羽化率和成虫性比均无显著影响。表明单宁酸对淡色库蚊幼虫的影响主要是延迟其生长发育,且影响程度与蚊虫对氰戊菊酯的敏感性有关。

The tannic acid is one of plant allelochemicals. In order to evaluate the potential of tannins in the larval control of noxious mosquitoes, the toxicity of tannic acid to 1st - 4th instar larvae of the fenvalerate-resistant and susceptible strains of Culex pipiens paUens was investigated in the laboratory, and the impact of tannins on the development of larvae was also observed. The results indicated that the larvae of the susceptible strain was more sensitive to tannins than that of the fenvalerate-resistant strain, and the sensitivity of the former to tannins was 6.4, 4.9, 4.7 and 2.0 times as high as that of the latter for 1 st - 4th instar larvae, respectively. Among larvae of all instars of the two strains, the first instar larvae were always the most sensitive to tannins, while the third instar larvae appeared to be the most insensitive. In the solution of 1 000 mg/L tannins, the survival rate of larvae of the two strains declined with the rearing time. The survivors of larvae exposed to 100 - 500 mg/L tannic acid solutions had slower development than the control larvae in both strains, and the developmental duration from the first instar to pupation delayed 34.5 - 38.3 h for the susceptible strain and 59.2- 93.4 h for the fenvalerate-resistant strain. Furthermore, the developmental duration of lst- 4th instar larvae were significantly different （P 〈 0.05 ） between the control and the treatment when the concentration of tannic acid for the treatment was 125 mg/L in the susceptible strain and 250 mg/L in the fenvalerateresistant strain. However, treating the first instar larvae of the two strains with 100 - 250 mg/L concentrations of tannic acid had no influence on the pupation, emergence and adult sex ratio of the survivors. The results suggested that tannic acid affected mainly the developmental duration of C. pipiens pallens larvae and the degree of influence was related to the susceptibility of larvae to fenvalerate.