Department of Entomology, Michigan State University, East Lansing, MI 48824, USA.
J Econ Entomol. 2010 Aug;103(4):1080-5. doi: 10.1603/ec10024.
Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae), a gregarious larval endo-parasitoid, is one of three biocontrol agents from Asia currently being released in the United States to combat the invasive emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae). The current protocol for rearing T. planipennisi involves presenting the wasps with artificially infested ash sticks made by placing field-collected larvae into shallow grooves beneath flaps of bark. Although third and fourth instars are readily accepted by T. planipennisi in these exposures, the suitability of younger or older developmental stages, which are often more readily available in the field, has not been tested. In this study, we used both artificially infested ash sticks and naturally infested ash logs to test which emerald ash borer developmental stages (second to fourth instars, J larvae [preprepupae], prepupae, and pupae) are most suitable for rearing T. planipennisi. T. planipennisi parasitized all stages except for pupae, but parasitized fewer J larvae and prepupae in naturally infested logs than in artificially infested ash sticks. This is probably because, in naturally infested ash logs, these stages were confined to pupal chambers excavated in the sapwood and may have been largely beyond the reach of ovipositing T. planipennisi. The number of T. planipennisi progeny produced was positively correlated (logarithmic) with host weight, but this relationship was stronger when J larvae and prepupae were excluded from the data set. Fourth instars yielded the most parasitoid progeny, followed by, in approximately equal numbers, J larvae, prepupae, and third instars. Second instars yielded too few parasitoid progeny to benefit rearing efforts.
平腹小蜂（Hymenoptera: Eulophidae）是一种群居性幼虫内寄生蜂，是目前正在美国释放的三种亚洲生物防治剂之一，用于防治入侵的绿柄天牛（Agrilus planipennis Fairmaire）（鞘翅目：扁甲科）。目前饲养平腹小蜂的方案涉及用人工饲养的灰棒来饲养黄蜂，即将野外收集的幼虫放入树皮下的浅沟中。虽然在这些暴露下，三龄和四龄幼虫很容易被平腹小蜂接受，但尚未测试更年轻或更年长的发育阶段（通常在野外更容易获得）的适宜性。在这项研究中，我们使用人工饲养的灰棒和自然感染的灰原木来测试绿柄天牛的哪些发育阶段（二至四龄幼虫、J 幼虫[预蛹]、预蛹和蛹）最适合饲养平腹小蜂。平腹小蜂寄生了所有阶段，除了蛹，但在自然感染的原木中寄生的 J 幼虫和预蛹比在人工饲养的灰棒中少。这可能是因为，在自然感染的灰原木中，这些阶段被限制在木质部中挖掘的蛹室中，可能很大程度上超出了产卵的平腹小蜂的范围。平腹小蜂后代的数量与宿主体重呈正相关（对数），但当排除 J 幼虫和预蛹时，这种关系更强。四龄幼虫产生的寄生蜂后代最多，其次是 J 幼虫、预蛹和三龄幼虫，数量大致相等。二龄幼虫产生的寄生蜂后代太少，不利于饲养工作。
