Data from: Succession and dynamics of Pristionchus nematodes and their microbiome during decomposition of Oryctes beetles on La Réunion Island

Insects and nematodes represent the most species-rich animal taxa and they occur together in a variety of associations. Necromenic nematodes of the genus Pristionchus are found on scarab beetles with more than 30 species known from worldwide samplings. However, little is known about the dynamics and succession of nematodes and bacteria during the decomposition of beetle carcasses. Here, we study nematode and bacterial succession of the decomposing rhinoceros beetle Oryctes borbonicus on La Réunion Island. We show that Pristionchus pacificus exits the arrested dauer stage seven days after the beetles´ deaths. Surprisingly, new dauers are seen after 11 days, suggesting that some worms return to the dauer stage after one reproductive cycle. We used high-throughput sequencing of the 16S rRNA genes of decaying beetles, beetle guts and nematodes to study bacterial communities in comparison to soil. We find that soil environments have the most diverse bacterial communities. The bacterial community of living and decaying beetles are more stable but one single bacterial family dominates the microbiome of decaying beetles. In contrast, the microbiome of nematodes is relatively similar even across different families. This study represents the first characterization of the dynamics of nematode-bacterial interactions during the decomposition of insects.

昆虫与线虫（nematodes）是物种丰富度最高的两类动物类群，二者以多样的生态关联形式共存。平咽线虫属（Pristionchus）的食尸性线虫常附着于金龟子体表，全球采样已发现该属线虫逾30种。然而，学界对金龟子尸体分解过程中线虫与细菌的动态变化及群落演替规律仍知之甚少。本研究以留尼旺岛上的波旁独角仙（Oryctes borbonicus）为研究对象，探究其分解过程中线虫与细菌的群落演替。研究发现，太平洋平咽线虫（Pristionchus pacificus）会在金龟子死亡7天后脱离停滞的dauer滞育期（dauer stage）。令人意外的是，在分解第11天后又观测到了新的dauer幼虫，这表明部分线虫在完成一轮生殖周期后会重新进入dauer滞育期。本研究通过对腐烂金龟子、金龟子肠道及线虫体内的16S rRNA基因进行高通量测序，并以土壤菌群作为对照解析细菌群落结构。结果显示，土壤环境中的细菌群落多样性最高；存活与腐烂状态下的金龟子体内细菌群落更为稳定，但腐烂金龟子的微生物组会被单一细菌科主导。与之形成对比的是，即使隶属于不同分类科的线虫，其体内微生物组也相对相似。本研究首次揭示了昆虫尸体分解过程中线虫与细菌互作的动态变化规律。