半闭弯尾姬蜂的寄主选择性及寄生对寄主发育和取食的影响

在24℃下研究了半闭弯尾姬蜂寄生对寄主幼虫龄期的选择性及对寄主生长发育、取食量的影响.结果表明,该蜂能寄生小菜蛾2～4龄的幼虫,但当2～4龄幼虫同时存在时,偏爱寄生2、3龄幼虫,对2、3、4龄幼虫的选择系数分别为0.37、0.44、0.19.该蜂对4龄幼虫的寄生能力随寄主日龄增大而下降.2～4龄小菜蛾幼虫被寄生后,总发育历期与预蛹期都比未被寄生的显著延长.当小菜蛾幼虫在2龄初被寄生后,总取食量比未被寄生的显著减少;但当幼虫在3、4龄初被寄生后,各龄的取食量与未被寄生的差异不显著.

菜蛾绒茧蜂的寄主选择性及寄生对寄主发育和取食的影响

研究了菜蛾绒茧蜂寄生对寄主幼虫龄期的选择性及对寄主生长发育、取食量的影响。结果表明,该蜂能寄生小菜蛾各个龄期的幼虫,但当2～4龄幼虫同时存在时,偏爱寄生2、3龄幼虫,对2、3、4龄幼虫的选择系数分别为0.37、0.39、0.24。该蜂对4龄幼虫的寄生能力随寄主日龄增大而急剧下降,对进入4龄并发育至该龄期40％时间以上的幼虫不能寄生。产卵寄生的雌蜂比例也随4龄幼虫日龄增大而急剧下降。小菜蛾幼虫被寄生后,其4龄发育历期较未被寄生的显著长,且寄生时龄期越大4龄历期延长越多。被寄生的幼虫取食量较未被寄生的显著增加,但均不能正常化蛹。文中还对田间该蜂寄生率估计方法进行了讨论。

瓜螟绒茧蜂田间发生动态及其对瓜螟的寄生作用

研究了瓜螟绒茧蜂Apanteles taragamae Viereck的田间消长动态和对瓜螟幼虫龄期的选择，及其寄生对瓜螟幼虫发育历期和取食量的影响。结果表明，瓜螟绒茧蜂全年均可寄生，其中以温度较低季节（上年10月至翌年3月）寄生率较高，为14．33％～29．73％；温度较高季节（4-9月）寄生率较低，仅为2．26％～8．54％；瓜螟绒茧蜂能寄生瓜螟1～3龄幼虫。当1～3龄幼虫同时存在时，偏爱寄生2龄幼虫。在室内试验条件下，每雌24h内平均可寄生6．33头幼虫，对幼虫平均寄生率为15．83％；被寄生幼虫的历期有延长的趋势，其中4龄被寄生幼虫历期较正常幼虫的历期延长较为明显：瓜螟幼虫被寄生后的取食量极显著少于未被寄生幼虫的取食量。研究结果认为，瓜螟绒茧蜂是一种值得保护和利用的寄生蜂。

Study on Developmental Durations and Fecundity of Phenacoccus solenopsis Tinsley on Four Species of Hosts

[Objective] The aim was to study on the effect of hosts on development and reproduction of mealybug （Phenacoccus solenopsis Tinsley）. [Method] Observation was conducted on developmental durations and fecundity of Phenacoccus solenopsis Tinsley fed on Gossypium spp., Nicotiana tabacum, Solanum tuberosum L and Hibiscus rosa-sinensis. [Result] There were differences among all durations, generation durations and fecundities of the mealybug adult females. Specifically, the generation durations on cotton （Gossypium spp.）, tobacco（ Nicotiana tabacum）, potato （Solanum tuberosum L） and Hibiscus rosa-sinensis were 30.2, 28.2, 37.3, and 27.7 d, and the fecundities per female were 626.0, 417.2, 552.5, and 183.2 ind., respectively. [Conclusion] The mealybug would have strong pontential in population growth when fed on cotton, tobacco and potato.

副珠蜡蚧阔柄跳小蜂对蓝色长盾金小蜂寄生橡副珠蜡蚧的干扰作用

为明确副珠蜡蚧阔柄跳小蜂Metaphycus parasaissetiae Zhang&Huang对蓝色长盾金小蜂Scutellista caerulea Fonscolombe寄生橡副珠蜡蚧Parasaissetia nigra Nietner的干扰作用,于室内观察了寄主不同成虫阶段(产卵前期和产卵期)、副珠蜡蚧阔柄跳小蜂接蜂数量(3、10、20头和30头)、两种蜂接蜂间隔时间(2、4、6 d和8 d)等因素对两种寄生蜂寄生率和产卵量的影响。结果表明,寄主发育阶段对蓝色长盾金小蜂产卵量和寄生率均无显著影响。随着副珠蜡蚧阔柄跳小蜂接蜂数增加,蓝色长盾金小蜂的产卵量有所增加,但增加不显著。副珠蜡蚧阔柄跳小蜂接蜂数为3~30头时,蓝色长盾金小蜂寄生率均高于副珠蜡蚧阔柄跳小蜂;接入副珠蜡蚧阔柄跳小蜂后再接蓝色长盾金小蜂时,两种寄生蜂接蜂间隔时间对蓝色长盾金小蜂的寄生率及产卵量影响明显,间隔2 d时蓝色长盾金小蜂产卵量最高,为21.3粒;间隔4 d时,蓝色长盾金小蜂寄生率最高,为58.89%;但间隔8 d时蓝色长盾金小蜂的产卵量和寄生率下降至最低。研究结果表明,接入副珠蜡蚧阔柄跳小蜂后再接蓝色长盾金小蜂时,间隔时间在4 d内对蓝色长盾金小蜂没有影响,间隔时间超过4 d时对蓝色长盾金小蜂有明显干扰,试验结果可以为合理避免这两种寄生蜂种间竞争提供依据。

EFFECT OF HOST PLANTS AND INOCULUM FORMS ON THE INOCULUM POTENTIAL OF ARBUSCULAR MYCORRHIZAL FUNGI

The effects of inoculum forms (single-spore, multi-spores, or colonized root pieces) and host plants (Nicotiana tabacum L., Sorghum sudanense (Piper) Stapf, and Trifolium repens L.) on the development and inoculum potential (IP) of the arbuscular mycorrhizal fungi (AMF) :Glo-mus macrocarpum Tul & Tul, donuis mosseae (Nicol & Gerd.) Gerdemann & Trappe, Glomus ver-siforme (Karsten) Berch, and Sclerocystis sinu/osa Gerdemann & Bakhi cultured in pots were investigated. The lag phase of treatment with 50 spores or 0.5 g (fresh weight) of colonized root pieces was 4 weeks, much shorter than that of the treatment with 1 spore (8 weeks); the value of IP (VIP) and percentage of root colonization (PRC) of the former were greater than those of the latter. Only on the early stages of colonization was there difference between the 50 spores and the 0.5 g (fresh weight) of colonized root piece inoculation treatments. The EP per plant inoculated with 0.5 g (fresh weight) of colonized root pieces of AMF was greater than that of the other two treatments except G. versiforme on Nicotiana tabacum, while the PRC of the plants inoculated with 50 spores and 0.5 g (fresh weight) of colonized root pieces of AMF was higher than that of the 1 spore inoculation after 10 weeks. Trie VIP of AMF on Trifolium repens was significantly higher than that on the other two hosts. The VIP of G. mosseae, G. versiforme, and S. sinuosa was respectively greater than that of G. macrocarpum. This suggested that different species of AMF produced different VIP of the inoculum . Nicotiana tabacum was much better than the other host plants which used to be inoculated with single spore, and to produce inocula of AMF.