Raw sperm viability data and Figure S1 from Impact of immune activation on stored sperm viability in ant queens

Ant queens mate on a single occasion early in life and store millions of sperm cells in their spermatheca. By carefully using stored sperm to fertilize eggs, they can produce large colonies of thousands of individuals. Queens can live for decades and their lifetime reproductive success is dependent on their ability to keep stored sperm alive. Maintaining high sperm viability requires metabolic energy which could trade-off with other costly processes such as immunity. We tested the impact of immune activation on the survival of stored sperm by prompting Lasius niger ant queens to mount a melanization response and subsequently measuring sperm viability in their spermatheca. Since queens face different challenges that influence energy allocation depending on the life stage of their colony, we measured sperm viability after immune activation in both newly mated queens (incipient) and in queens 1 year after mating (established). We found that immune activation reduced sperm viability in established queens but not in incipient queens, showing that the cost of immunity on sperm preservation depends on the life stage. Unexpectedly, established queens had significantly higher sperm viability in their spermatheca compared to incipient queens suggesting that ant queens are able to remove dead sperm from their spermatheca.蚁后在生命早期仅进行单次交配，并将数百万枚精子存储于储精囊（spermatheca）中。通过精准调度存储的精子为卵子授精，蚁后可培育出拥有数千只个体的大型蚁群。蚁后寿命可达数十年，其终身繁殖成功率完全依赖于维持存储精子活性的能力。维持高水平精子活性需要消耗代谢能量，而这一需求可能与免疫等其他高成本生理过程存在能量权衡。 本研究以黑毛蚁（Lasius niger）蚁后为实验对象，通过诱导其产生黑化反应（melanization response），随后检测储精囊内的精子活性，以此探究免疫激活对存储精子存活状态的影响。鉴于蚁后会根据蚁群的生命周期阶段面临不同的能量分配挑战，我们分别对初交配蚁后（incipient，新建蚁群阶段）以及交配后1年的成熟种群蚁后（established，成熟蚁群阶段）开展免疫激活处理，并检测其精子活性。 实验结果显示，免疫激活会降低成熟种群蚁后的精子活性，但对新建种群蚁后无显著影响，这表明免疫对精子保存的代价依赖于蚁群的生命周期阶段。出乎意料的是，成熟种群蚁后储精囊内的精子活性显著高于初交配蚁后，这提示蚁后能够主动清除储精囊内的死亡精子。