摘要
在实验室内研究了本地天敌拟澳洲赤眼蜂和外来天敌短管赤眼蜂在不同卵龄和不同空间条件下对小菜蛾卵的寄生和种间竞争。结果表明,在0～6 2 h的小菜蛾卵上,拟澳洲赤眼蜂和短管赤眼蜂单独接蜂时对小菜蛾卵的寄生率、子代羽化率、子代雌蜂百分率随卵龄下降,而后代发育死亡率则随卵龄增加。短管赤眼蜂对各龄小菜蛾卵的寄生率、子代羽化率、子代雌蜂百分率均较拟澳洲赤眼蜂高,而子代蜂的发育死亡率则较拟澳洲赤眼蜂低。两种蜂对小菜蛾卵龄的要求都不太严格,在小于4 8h的小菜蛾卵上都能产卵寄生,且寄生率高于5 0 % ,但短管赤眼蜂寄生对小菜蛾卵龄的要求更宽松。在两种蜂混合接蜂时,后代中短管赤眼蜂的比例在各处理中都高于5 0 % ,且随寄主卵龄增加,当小菜蛾卵龄大于4 8h后,短管赤眼蜂的比例高达10 0 % ,说明短管赤眼蜂对小菜蛾有更强的寄生能力和竞争能力。拟澳洲赤眼蜂和短管赤眼蜂单独接蜂时,在4～2 2 cm3空间范围内,各处理间对小菜蛾卵的寄生率没有显著差异,而短管赤眼蜂的寄生率(76 .4 %～86 % )略低于拟澳洲赤眼蜂(88.7%～92 .3% )。当空间大于5 3cm3时,寄生率显著下降,在10 2 cm3空间时显著降低到5 0 %。混合接蜂时各处理间寄生率差异不显著。两种接蜂方式对后代羽化率和雌蜂百分率没有太大影响,蜂的后?
The diamondback moth (DBM), Plutella xylostella (L.), is an important, damaging insect of cruciferous crops worldwide and since the 1970s has been the most serious insect pest on crucifers in South China. Indiscriminate use of synthetic broad-spectrum chemicals for control of DBM has led to the development of serious resistance. Therefore alternative control programs including biological control of DBM are needed urgently. Egg parasitoids of the genus Trichogramma have been used in biological control for almost 100 years, but use of Trichogramma to control DBM has a history of only ten years. To date, the research on trichogrammatid egg parasitoids of P. xylostella has mainly focused on the selection of suitable species and strains. T. confusum Viggiani and T. pretiosum Riley have been identified as the most effective species of Trichogramma to control DBM in laboratory studies. T. confusum is a predominant and indigenous natural egg parasitoid of DBM in South China while T. pretiosum is a predominant parasitoid of Heliothis in the U.S.A. and was imported to our University in 1995. This study compared the parasitizing ability of the two Trichogrammatid species and also investigated the possible environmental risks posed by the exotic species by evaluating interspecific competition of T. confusum and T. pretiosum on DBM eggs. Experiments were conducted in controlled environment chambers at 28°C, 70% RH and 24h dark. In the first experiment, two mated females of T. confusum or T. pretiosum (single species group) or 1 female adult of T. confusum and 1 female adult of T. pretiosum together (mixed group) were placed inside a 4 cm^3 cuvette with 50 DBM eggs for 24 hours. The ages of DBM eggs tested were 0,12,24,36,48,54,62 hours old, respectively and there were 30 replicates for each treatment. Parasitism, emergence and percentage of female progeny decreased with the host egg age in both single species and mixed species groups, but progeny mortality during development increased with the host egg age. Single species groups of T. pretiosum had higher parasitism, emergence, percentage of female progeny and lower progeny mortality than T. confusum. Both parasitoids achieved more than 50% parasitism at all egg ages < 48 hours but T. pretiosum had a wider age selection for DBM eggs than T. confusum. In the mixed species group the proportion of T. pretiosum in the progeny was more than 50% at all host egg ages and reached 100% when eggs were > 48 hours, which indicated T. pretiosum has an increasing competitive ability on the older host eggs when in interspecific competition with T. confusum. In the second experiment, 50 newly laid DBM eggs were exposed to two mated females of T. confusum or T. pretiosum or to 1 female adult of T. confusum and 1 female adult of T. pretiosum together inside a cuvette of 4 cm^3、8 cm^3、22 cm^3、53 cm^3 and 102cm^3 volumes for one day, respectively, with 30 replicates for each. In the single species group, parasitism did not differ significantly with a cuvette volume of 4~22cm^3 for both parasitoids, but parasitism rates of T. pretiosum (76.7%~86%) were slightly lower than T. confusum (88.7%~92.7%). When the cuvette volume increased above 53 cm^3, parasitism of both parasitoids decreased significantly. Parasitism rates were not affected by cuvette volume in the mixed species group but the proportion of T. pretiosum in the progeny decreased from 80% to 20% when the cuvette volume increased from 4cm^3to 102cm^3, which implied the competitive ability of T. pretiosum was reduced with increased space.
出处
《生态学报》
CAS
CSCD
北大核心
2005年第4期837-841,共5页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目 (3 993 0 12 0
3 0 3 70 966)~~
关键词
拟澳洲赤眼蜂
短管赤眼蜂
小菜蛾
寄生能力
种间竞争
Trichogramma confusum Viggiani
T. pretiosum Riley
Plutella xylostella L.
parasitizing ability
interspecific competition
