Okumura Etsuko, Ishikawa Yuji, Tanaka Ryusei, Yoshiga Toyoshi
Department of Applied Biological Sciences, Faculty of Agriculture, Saga University, Japan.
Zoolog Sci. 2013 Mar;30(3):174-7. doi: 10.2108/zsj.30.174.
We demonstrated the disembarkation of the bacterial-feeding nematode Caenorhabditis japonica dauer larvae (DL) from adult Parastrachia japonensis female insects and observed the propagation of nematodes in artificial insect nests. Our results clarify the process of propagation in this nematode species and provide insights into the nematode-insect relationship. Quiescent C. japonica DL resumed their mobility only at > 99.9% relative humidity (RH) at 25°C in the presence or absence of the carrier insect. In artificial nests with > 99.9% RH, DL resumed their mobility and the number of DL on female insects decreased gradually after oviposition, although numerous DL remained on the insects. Very few DL were detected on mother insects after hatching. Nematode propagation was observed on the egg mass after hatching and on nymphal carcasses; the total number of nematodes in the nest increased dramatically after this point. These results indicate that humidity is an important factor for disembarkation of C. japonica DL and that C. japonica propagates in the nest of P. japonensis where it feeds on the remains of eggs and nymph carcasses, indicating that C. japonica and P. japonensis have a unique phoretic and necromenic association.
我们展示了食细菌线虫日本秀丽隐杆线虫 dauer 幼虫（DL）从成年日本拟蝎蛉雌性昆虫身上脱离，并观察了线虫在人工昆虫巢穴中的繁殖情况。我们的结果阐明了这种线虫物种的繁殖过程，并为线虫与昆虫的关系提供了见解。静止的日本秀丽隐杆线虫 DL 仅在 25°C、相对湿度（RH）>99.9%的条件下，无论是否存在携带昆虫，都会恢复活动。在相对湿度>99.9%的人工巢穴中，DL 恢复活动，产卵后雌性昆虫身上的 DL 数量逐渐减少，尽管仍有大量 DL 留在昆虫身上。孵化后在母虫身上检测到的 DL 非常少。孵化后在卵块和若虫尸体上观察到了线虫繁殖；此后巢穴中线虫总数急剧增加。这些结果表明，湿度是日本秀丽隐杆线虫 DL 脱离的重要因素，并且日本秀丽隐杆线虫在日本拟蝎蛉的巢穴中繁殖，以卵和若虫尸体的残骸为食，这表明日本秀丽隐杆线虫与日本拟蝎蛉具有独特的携带和尸食性关联。
