枸杞木虱啮小蜂寄生生物学研究

枸杞木虱啮小蜂(Tamarixia lyciumiYang)(新种)是枸杞木虱(Paratrioza sinicaYangLi)若虫期的重要寄生性天敌。第1~3日龄的木虱啮小蜂寄生寄主的能力较强。最喜寄生枸杞木虱4龄若虫,其次为5龄和3龄若虫。1头蜂一般一次只产1粒卵,寄生1头寄主,对已被寄生的寄主具有明显的辨别能力。在试验条件下,不能在沙枣木虱和柽柳木虱等其他寄主上产卵寄生,只寄生于枸杞木虱。对不同龄期(3、4、5龄)枸杞木虱若虫的功能反应均符合HollingⅡ型反应,相同寄主密度下,4龄时寄生数量最大,拟合的圆盘方程为:Na=0.560 9N/(1+0.027 1N)。枸杞木虱啮小蜂具有较强的种内干扰作用,随自身密度(P)的增加,对枸杞木虱4龄若虫的发现域(a)随之降低,用Hassell-Varley模型拟合为:a=0.122 2P-0.464 1。

Studies on parasitic biology of Tamarixia lyciumi

The parasitic characteristics of Tamarixia lyciumi Yang, a new parasitoid of nymphal Paratrioza sinica Yang &; Li, were studied under laboratory conditions. The 1~3 days old T. lyciumi had stronger parasitic ability, which preferred the 4th nymphal stage to the 3rd and 5th nymphal stages of P. sinica. One female, laying one egg and parasitizing one nymph at a time, could identify its host easily. Under the controlled conditions, T. lyciumi would never lay eggs on the nymph of Trioza magnisetosa Log. and Eustigmata tamaricina Log., but of Paratrioza sinica. The parasitic functional response of T. lyciumi adults was also studied. The results showed that the response fitted the Holling Type Ⅱ equation. Supplying the host at the same instar stage, the number of the parasitized was highest when the host was at 4th instar stages, and the equation was Na=0.964 9N/(1+0.313N). The relationships between the discovered area (a) of T. lyciumi and its density (P) could be well simulated as a=0.122 2P-0.464 1 by Hassell Varley (1969) model a=QP-m, with the 4th instar stage of P. sinica as the host.