Fecundity experiment

We compared fecundity of 3 longstanding laboratory colonies (1st exp) and of 2 longstanding lab colonies and colonies recently established from field collected individuals (2nd exp). Female wasps were individually paired for 24 h in small vials with a conspecific male. Females were then placed individually in arenas with leaf disks bearing about 80 whitefly nymphs. The leaf disks rested on a layer of agar in ventilated 35 mm agar Petri dishes. Females were transferred to new whitefly-infested arenas every other day until day eight. At day 4, we provided females with the opportunity to mate again to avoid the risk of sperm depletion by introducing a male into the arena for 24h. Arenas were kept at 27°C, 16L:8D, and 65% RH. After females were removed on day 8, arenas were incubated for approximately 10 more days. At the end of this period, we recorded the number of progeny pupae, a proxy for adult emergence, as a measure of fecundity.

我们开展了两项对比试验：第一项试验比较3个长期实验室饲养种群的繁殖力，第二项试验则比较2个长期实验室饲养种群与近期由野外采集个体建立的种群的繁殖力。试验过程中，将雌性寄生蜂与1只同种雄蜂置于小型试管内单独配对24小时。随后将每头雌蜂单独转移至饲养容器中，容器内放置有携带约80头烟粉虱若虫的叶碟，叶碟则置于通风式35mm琼脂培养皿内的琼脂层之上。每间隔1天将雌蜂转移至新的携虫饲养容器中，直至第8天。在第4天时，我们向饲养容器内放入1只雄蜂并维持24小时，为雌蜂提供再次交配的机会，以规避精子耗竭的风险。所有饲养容器均保持在温度27℃、光周期16L:8D、相对湿度65%的环境条件下。待第8天移除雌蜂后，将饲养容器继续孵育约10天。试验结束时，我们统计子代蛹的数量——该指标可作为成虫羽化量的替代评价指标，以此量化雌蜂的繁殖力。