Fungus-growing termites (Isoptera: Macrotermitinae) dominate African savannah ecosystems where they play important roles in ecosystem functioning. Their ecological dominance in these ecosystems has been attributed to living in an ectosymbiosis with fungi of the genus Termitomyces (Lyophyllaceae). Evolutionary theory predicts that the transmission mode of a symbiont determines cooperation and conflict between host and symbiont with vertical transmission (co-transmission of host and symbiont offspring to the next generation) leading to less conflict than horizontal transmission (symbionts are acquired by the host from the environment). Thus, one can hypothesize associations with vertical transmission to be ecological more successful than those with horizontal transmission. We tested this by analyzing whether there is an association between transmission mode and fungus-growing termite species abundance and distribution in West-African savannah and forest ecosystems. We used data from a total of 78 study sites comprising protected National Parks as well as anthropogenically disturbed ecosystems, covering Benin, Côte d'Ivoire, and Togo. Our results showed that, in contrast to expectation, species with horizontal symbiont transmission were more common. We encountered more often species with horizontal than vertical transmission. This result might be due to the fact that only five out of the 25 identified fungus-growing termite species had vertical transmission. Yet, species with horizontal transmission also had higher relative abundances within study sites than those with vertical transmission. Thus, transmission mode is unlikely to explain abundance differences between fungus-growing termite species.

中文翻译：

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共生体传播模式的差异能否解释西非真菌生长白蚁的丰度和分布？

生长真菌的白蚁（等翅目：Macrotermitinae）在非洲大草原生态系统中占主导地位，它们在生态系统功能中发挥着重要作用。它们在这些生态系统中的生态优势归因于与 Termitomyces (Lyophyllaceae) 属的真菌共生。进化论预测，共生体的传播方式决定了宿主与共生体之间的合作和冲突，垂直传播（宿主和共生体后代共同传播给下一代）导致的冲突比横向传播少（共生体从宿主获得环境）。因此，人们可以假设与垂直传播的关联比那些与水平传播的关联在生态上更成功。我们通过分析传播模式与西非大草原和森林生态系统中真菌生长的白蚁物种丰度和分布之间是否存在关联来测试这一点。我们使用了总共​​ 78 个研究地点的数据，这些地点包括受保护的国家公园以及人为干扰的生态系统，涵盖贝宁、科特迪瓦和多哥。我们的结果表明，与预期相反，具有水平共生传播的物种更为常见。我们遇到的更多是水平传播而不是垂直传播的物种。这一结果可能是因为在 25 种已鉴定的真菌生长白蚁物种中，只有 5 种具有垂直传播。然而，水平传播的物种在研究地点内的相对丰度也高于垂直传播的物种。因此，