寄主大小对副珠蜡蚧阔柄跳小蜂产卵选择及繁殖的影响

Effect of host size on the oviposition selection and reproduction of Metaphycus parasaissetiae

为明确寄主体型大小对副珠蜡蚧阔柄跳小蜂产卵选择及繁殖的影响,在室内观察了副珠蜡蚧阔柄跳小蜂在不同大小的橡副珠蜡蚧上的产卵量、寄生率、发育历期及性比。结果表明:在选择性和非选择性的产卵试验条件下副珠蜡蚧阔柄跳小蜂对中型个体寄主(长4.0 mm,宽3.4 mm)的寄生率最高;小蜂的产卵量在选择性试验时,以大型寄主(长4.8 mm,宽4.0 mm)体内的最高(67.0粒),非选择性试验时,以中型寄主(长4.0 mm,宽3.4 mm)体内的最高(131.0粒),小型寄主(长3.2 mm,宽2.9 mm)体内产卵量最少(61.5粒);副珠蜡蚧阔柄跳小蜂后代出蜂数与寄主体型的大小呈显著正相关,雌性比则随寄主体型的增大而增减小,发育历期则受寄主体型的影响不明显。综上所述,副珠蜡蚧阔柄跳小蜂雌蜂能够根据寄主质量来调整产卵量及后代性比,以使后代适应度最大化。

To clarify the effect of host size on the oviposition selection and reproduction of Metaphycus parasaissetiae, the fecundity, parasitic rate, developmental duration and sex ratio were studied on the different size Parasaissetia nigra. The results showed that the parasitic rate of M. parasaissetiae was highest on middle size P. nigra （ length 4. 0 mm, width 3. 4 mm） in choice and non-choice tests. In choice test, the fecundity was highest （67. 0 eggs） on big P. nigra （ length 4. 8 mm, width 4. 0 mm） . In non-choice test, the highest （131. 0 eggs） and lowest （61. 5 eggs） fecundity were observed on middle and small P. nigra, respectively. The number of M. parasaissetiae offspring had significant positive correlation with the host size. The female ratio decreased with the increasing of host size. The host size did not affect the developmental duration of M. parasaissetiae. In conclusion, the parasitoid M. parasaissetiae can adjust theirs fecundity and progeny sex ratio to ensure the maximum offspring suitability according to the host quality.