Mechanisms of intra- and interspecific competition among wasps parasitic on bean weevil larvae.

对寄生蜂幼虫种内和种间竞争的机理进行了实验分析。本研究以中国豆象的三种寄生蜂-异翅蜂Anisopteromalus calcium、底蜂Dinarmus basalis和异距蜂Heterospilus prosopterium为试材，首次证实了这三种寄生蜂均表现出重寄生和多寄生现象。利用专为本研究设计的观察板，观察了种内和种间幼虫的竞争。我们得到了以下结果。1.同种卵的同时引入，总是从一个宿主产生一个小蜂后代。时滞引进两个同种卵也只产生一个黄蜂后代。哪一个个体出现取决于时间间隔。在72或96小时的时滞下，第一个来的总是赢。然而，由于有48小时的时滞，迟到者总是获胜。异种卵的同时引入表明，任何一个物种都不存在种间幼虫竞争的先天优势.异源卵的时滞引进表明，第一个到达者总是赢得竞争。时滞越长，先到者越强。

The mechamisms of intra- and interspecific competition between larvae of parasitic wasps were analyzed experimentally. We used three species, Anisopteromalus calandrae, Dinarmus basalis, and Heterospilus prosopidis, all of which are larval perasitoids on Callosobruchus chinensis.We first confirmet that these three wasp species actually showed superand multiparasitisms. We observed the intra- and interspecific larval competitions using the observation plate specifically designed for this research. We obtained the following results.1. Simultaneous introductions of conspecific eggs produced invariably one wasp offspring from one host.2. Time-lag introductions of two conspecific eggs also produced only one wasp offspring. Which individual emerged depended on the time-lag. With 72 or 96 hrs time-lag, the first comer always won. However,with 48 hrs time-lag, the late comer always won.3. Simultaneous introductions of heterospecific eggs showed that there was no inherent superiority in any species for interspecific larval competition.4. Time-lag introductions of heterospecific eggs showed that the first comer always won the competition. The longer the time-lag, the stronger the first comer was.