Subfossil chironomids are regarded as a useful biological proxy for palaeoenvironmental research, but picking chironomid head capsules from aquatic sediments is extremely time-consuming. This is often the case for finding and isolating small head capsules from the deflocculated sediment. In this study, two stains (aniline blue and cotton blue) were used to dye chironomid head capsules in lake and peat sediments to improve the traditional pretreatment method and boost the picking efficiency. The results suggested that: (1) there were sharp contrasts between chironomids and residues after staining, which could shorten picking time for both lake and peat samples; (2) different parts of head capsules showed distinctive colour in stained samples and thus facilitated identification and taxonomy of subfossil chironomids; (3) the dyeing effects of two stains were comparable and no significant effect of staining on chironomid composition has been observed compared with unstained samples. This study demonstrates that aniline blue and cotton blue stain can promote picking efficiency of subfossil chironomids, and can be widely applied to pretreatment of sedimentary chironomids in palaeoenvironmental studies on lakes and peatlands.

亚化石的拟南芥被认为是古环境研究的有用的生物替代物，但是从水生沉积物中选择拟南芥的头囊非常耗时。这通常是从絮凝的沉积物中找到并分离出小的水头囊的情况。在这项研究中，两种染色剂（苯胺蓝和棉蓝）被用于染色湖泊和泥炭沉积物中的鳞茎头囊，以改善传统的预处理方法并提高采摘效率。结果表明：（1）染色后手性虫与残留物之间形成鲜明的对比，可以缩短湖泊和泥炭样品的采摘时间；（2）头囊的不同部位在染色样品中显示出独特的颜色，从而有助于亚化石钟表虫的鉴定和分类。（3）两种染色剂的染色效果相当，与未染色样品相比，没有观察到染色剂对尺虫的组成有明显影响。这项研究表明，苯胺蓝和棉蓝染色剂可以提高亚化石基虫的采摘效率，并可以广泛地应用于湖泊和泥炭地古环境研究中的沉积基虫的预处理。