Laboratoire de Bactériologie, Faculté de Médecine Lyon Est, site Laennec, INSERM U851, Rue Guillaume Paradin, Université de Lyon, Lyon, France.
Ecol Lett. 2012 Jun;15(6):603-10. doi: 10.1111/j.1461-0248.2012.01774.x. Epub 2012 Apr 4.
The potential role of pathogens or parasites in maintaining species coexistence is well documented. However, the impact of vertically transmitted symbionts, that can markedly modify their host's biology, is largely unknown. Some females of the Drosophila parasitoid Leptopilina boulardi are infected with an inherited virus (LbFV). The virus forces females to lay supernumerary eggs in already parasitised hosts, thus allowing its horizontal transmission. Using two independent experimental procedures, we found that LbFV impacts inter-specific competition between L. boulardi and the related L. heterotoma. While L. boulardi rapidly outcompetes L. heterotoma in the absence of the virus, L. heterotoma was able to maintain or even to eliminate L. boulardi in the presence of LbFV. By forcing females to superparasitise, LbFV induced egg wastage in L. boulardi thus explaining its impact on the competition outcome. We conclude that this symbiont whose transmission is L. boulardi-density-dependant may affect the coexistence of Leptopilina species.
病原体或寄生虫在维持物种共存方面的潜在作用已有充分记录。然而，垂直传播共生体的影响，这些共生体可以显著改变宿主的生物学特性，在很大程度上还不清楚。某些寄生性蝇类 Leptopilina boulardi 的雌性个体感染了一种遗传病毒（LbFV）。该病毒迫使雌性在已被寄生的宿主中产下多余的卵，从而允许其水平传播。使用两种独立的实验程序，我们发现 LbFV 影响了 L. boulardi 和相关的 L. heterotoma 之间的种间竞争。虽然在没有病毒的情况下，L. boulardi 能够迅速战胜 L. heterotoma，但在存在 LbFV 的情况下，L. heterotoma 能够维持甚至消除 L. boulardi。通过迫使雌性过度寄生，LbFV 导致 L. boulardi 的卵浪费，从而解释了其对竞争结果的影响。我们得出结论，这种共生体的传播依赖于 L. boulardi 的密度，可能会影响 Leptopilina 物种的共存。
