Wajnberg Eric, Cônsoli Fernando L
INRAE Sophia Antipolis Cedex France.
INRIA Projet Hephaistos Sophia Antipolis Cedex France.
Ecol Evol. 2024 Dec 3;14(12):e70676. doi: 10.1002/ece3.70676. eCollection 2024 Dec.
Most insects harbour endosymbionts that modify their physiology, reproductive mode, and ecology. One fascinating case is in aphids, which host endosymbionts that protect them against attacks from parasitoids. These symbionts are transmitted maternally with high fidelity but can also be transmitted horizontally from infected to uninfected hosts. Since symbionts can confer resistance to their host against parasitoids, levels of symbiont infection should rapidly spread to fixation. This is not the case in most aphid populations that have been studied. Furthermore, the defensive effect of symbionts has been thought to reduce the efficacy of biological control against crop pests, although this has never been properly quantified. We developed a Monte Carlo simulation model to examine changes in levels of endosymbiont infection in an insect population in the presence of parasitoids attacking them over several generations. We also used the model to quantify potential reductions in the efficacy of parasitoids in controlling host populations in biological control. Results suggest that longevity of parasitoids and the spatial aggregation of hosts likely play a major role in the dynamics of symbiont infection. This is the first evidence that these ecological parameters are potentially important for explaining levels of symbiont infection in insect populations.
大多数昆虫体内都携带着内共生体，这些内共生体会改变它们的生理机能、繁殖方式和生态习性。一个有趣的例子是蚜虫，它们体内的内共生体能够保护它们免受寄生蜂的攻击。这些共生体通过母体以高保真度进行传播，但也可以从受感染的宿主水平传播到未受感染的宿主。由于共生体能够赋予宿主对寄生蜂的抗性，共生体感染水平应该会迅速传播并固定下来。然而，在大多数已研究的蚜虫种群中并非如此。此外，尽管共生体的防御作用从未得到过恰当的量化，但人们一直认为它会降低对农作物害虫进行生物防治的效果。我们开发了一个蒙特卡洛模拟模型，以研究在几代时间里存在寄生蜂攻击的情况下昆虫种群内共生体感染水平的变化。我们还使用该模型来量化寄生蜂在生物防治中控制宿主种群的效果可能会出现的潜在降低情况。结果表明，寄生蜂的寿命和宿主的空间聚集可能在共生体感染动态中起主要作用。这是首个证据表明这些生态参数对于解释昆虫种群中的共生体感染水平可能很重要。
