Queens stay, workers leave: caste-specific responses to fatal infections in an ant
Queens stay, workers leave: caste-specific responses to fatal infections in an ant
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DOI：
10.1186/s12862-018-1320-0
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发表时间：
2018-12-27
影响因子：
3.4
通讯作者：
Heinze, Juergen
中科院分区：
文献类型：
--
作者：
Giehr, Julia;Heinze, Juergen
背景动物社会中密切相关的个体之间的强烈相互作用为病原体的传播提供了完美的条件。因此，社会性昆虫已经在细胞、个体和社会水平上进化出对抗措施来降低感染风险。一个突出的例子是利他主义的自我去除，即，受致命感染的工蚁离开巢穴，在隔离中死去，以防止传染病传播给它们的同伴。因为繁殖女王和产卵工人的行为不如非产卵工人利他，例如，当谈到群体防御时，我们想知道垂死的产卵者是否会像非生殖工人一样表现出自我清除。此外，我们调查了致命感染如何影响繁殖，并研究了当蚁后和产卵工人的剩余繁殖价值下降时，他们是否会加强繁殖努力（终端投资）。结果我们处理了蜂王，来自无蜂王殖民地的产卵工人，以及来自一夫一妻制的女王权利殖民地的非产蛋工人（单蚁后）粗棘胸蚁与对照溶液或含有昆虫病原真菌褐色绿僵菌孢子的溶液。受致命感染的工蜂离开巢穴后，不管它们的生殖状况如何，都会在远离巢穴的地方死去。相比之下，受感染的蚁后从未离开过巢穴，只有在它们死后才被工蚁移走。对照溶液和褐绿僵菌悬液处理后，蜂王的生殖投资均显著下降。在无女王殖民地的产卵率最初减少感染的殖民地，但不是在控制殖民地。鸡蛋数量再次增加，感染workers.ConclusionsQueens和工人的蚂蚁Temnothorax crassispinus不同的感染风险和预期寿命降低的反应。工蚁会将自己隔离起来，以防止殖民地内的传染病，而蚁后则呆在巢穴里。我们没有发现终端投资;相反，似乎产蛋者完全关闭了产蛋，以应对致命的感染。无蜂王蜂群中的工蜂只有在所有受感染的个体死亡后才恢复繁殖，这可能也是为了尽量减少感染后代的风险。
BackgroundThe intense interactions among closely related individuals in animal societies provide perfect conditions for the spread of pathogens. Social insects have therefore evolved counter-measures on the cellular, individual, and social level to reduce the infection risk. One striking example is altruistic self-removal, i.e., lethally infected workers leave the nest and die in isolation to prevent the spread of a contagious disease to their nestmates. Because reproductive queens and egg-laying workers behave less altruistically than non-laying workers, e.g., when it comes to colony defense, we wondered whether moribund egg-layers would show the same self-removal as non-reproductive workers. Furthermore, we investigated how a lethal infection affects reproduction and studied if queens and egg-laying workers intensify their reproductive efforts when their residual reproductive value decreases (terminal investment).ResultsWe treated queens, egg-laying workers from queenless colonies, and non-laying workers from queenright colonies of the monogynous (single-queened) ant Temnothorax crassispinus either with a control solution or a solution containing spores of the entomopathogenic fungus Metarhizium brunneum. Lethally infected workers left the nest and died away from it, regardless of their reproductive status. In contrast, infected queens never left the nest and were removed by workers only after they had died. The reproductive investment of queens strongly decreased after the treatment with both, the control solution and the Metarhizium brunneum suspension. The egg laying rate in queenless colonies was initially reduced in infected colonies but not in control colonies. Egg number increased again with decreasing number of infected workers.ConclusionsQueens and workers of the ant Temnothorax crassispinus differ in their reaction to an infection risk and a reduced life expectancy. Workers isolate themselves to prevent contagion inside the colony, whereas queens stay in the nest. We did not find terminal investment; instead it appeared that egg-layers completely shut down egg production in response to the lethal infection. Workers in queenless colonies resumed reproduction only after all infected individuals had died, probably again to minimize the risk of infecting the offspring.