This study aimed to evaluate the structure, taxonomic, and trophic composition of an assemblage of chironomid larvae associated with leaf litter in a tropical stream (Brazilian Cerrado biome) during different seasonal periods. Additionally, the study aimed to examine the relationship between the activity of decomposing microorganisms and the abundance and total richness of chironomids. To conduct the study, leaves were collected in buckets from the Boiadeiro stream at five sampling points over 30 consecutive days, resulting in a total collection of 12 months. Then, they were placed in litter bags (n = 3 per point) and incubated in the stream for 30 days to evaluate chironomid colonization and microbial activity. A total of 3,892 chironomid larvae were identified. Among the functional feeding groups (FFGs) of chironomid larvae, the food collector-gatherer group displayed higher diversity than other FFGs. The richness of chironomids was positively associated with the number of conidia produced by aquatic hyphomycetes' during leaf decomposition. We found that during the dry season (April–August), the highest values of abundance and total richness of chironomids were recorded, accompanied by the lowest taxonomic variability of chironomid larvae. Conversely, environmental variations in the rainy season contributed to greater taxonomic variability but lower abundance and total richness of chironomids associated with leaf detritus.

本研究旨在评估不同季节期间热带溪流（巴西塞拉多生物群落）中与落叶层相关的摇蚊幼虫群落的结构、分类和营养组成。此外，该研究旨在研究分解微生物的活性与摇蚊的丰度和总丰富度之间的关系。为了进行这项研究，我们连续 30 天在五个采样点从博亚德罗溪流的桶中收集树叶，总共收集了 12 个月。然后，将它们放入垃圾袋中（每点 n = 3 个）并在溪流中孵育 30 天，以评估摇蚊定植和微生物活性。总共鉴定出 3,892 只摇蚊幼虫。在摇蚊幼虫的功能性摄食类群（FFG）中，食物采集-采集类群比其他功能性摄食类群表现出更高的多样性。摇蚊的丰富度与水生丝孢菌在叶片分解过程中产生的分生孢子的数量呈正相关。我们发现，在旱季（四月至八月），摇蚊丰度和总丰富度最高，同时摇蚊幼虫的分类变异性最低。相反，雨季的环境变化导致分类变异更大，但与叶碎屑相关的摇蚊丰度和总丰富度降低。