日本柄瘤蚜茧蜂与其寄主豆蚜的相互作用：寄主龄期选择及其对发育的影响

在25℃下研究了日本柄瘤蚜茧蜂Lysiphlebus japonicus Ashmead对寄主豆蚜Aphis craccivora Koch龄期的选择和被寄生豆蚜的龄期对蚜茧蜂发育的影响。结果表明：在混合虫态寄主中，日本柄瘤蚜茧蜂通常选择较小龄期的若蚜寄生，其中2龄若蚜的相对被寄生率最高，为26.4%；其次是1龄若蚜，为20.6%；无翅成蚜与3、4龄有翅若蚜和成蚜的相对被寄生率较低。日本柄瘤蚜茧蜂的寄生延长了豆蚜若蚜的发育，其中1龄若蚜被寄生后，１～３龄历期显著延长；有翅3龄若蚜被寄生后，３、４龄历期明显延长；但无翅和有翅4龄若蚜被寄生后的发育历期均不受影响。各龄若蚜被寄生后羽化的成蚜寿命明显缩短，其中，被寄生的1龄若蚜不能发育至成蚜，其它较早龄期被寄生的若蚜羽化的成蚜繁殖力均显著降低。寄生时寄主的发育期也影响寄生蜂的发育，2龄豆蚜被寄生时的日本柄瘤蚜茧蜂个体发育最快，为194.10 h；1龄寄主被寄生时蚜茧蜂的发育最慢，需215.80 h。并对不同发育期蚜虫总蛋白质和总糖原含量进行了测定。

Interactions between the parasitoid Lysiphlebus japonicus Ashmead and its host Aphis craccivora Koch: host-stage selection and its effect on development

Host-stage selection of Lysiphlebus japonicus Ashmead, a parasitoid of Aphis craccivora Koch and the effect of host stage being parasitized on the parasitoid development and fecundity were investigated at (25±1)℃. When aphids of mixed stages were provided, the parasitoid showed a preference for younger aphids to parasitize. The relative parasitism on the 2nd instar aphids was the highest (26.4%), followed by 1st instar aphids (20.6%), and rather low on the adults. The development of the aphids was delayed after being parasitized. The durations of the 1st, 2nd and the 3rd instar of the hosts significantly prolonged when 1st instar aphids were parasitized，and those of the 3nd and 4th instar were also markedly extended after alate were parasitized. However, no obvious influence on development of apterae and alate was observed after they were parasitized. The life span of the adults of the aphids parasitized at various nymphal stages sharply shortened. All of the parasitized 1st instar aphids turned to mummies before the adults. The fecundity of the adults from younger aphids parasitized distinctly declined in comparison with the control adults. Immature stage of the parasitoid In 2nd instar of the hosts developed the fastest with duration of 194.10h, and the slowest of 215.80h in 1st instar of the hosts.Total contents of protein and glycogen in A.craccivora of different stages were also assayed.