The immune and circulatory systems of mammals are functionally integrated, as exemplified by the immune function of the spleen and lymph nodes. Similar functional integration exists in the malaria mosquito, Anopheles gambiae, as exemplified by the infection-induced aggregation of hemocytes around the heart valves. Whether this is specific to mosquitoes or a general characteristic of insects remained unknown. We analyzed 68 species from 51 families representing 16 orders and found that infection induces the aggregation of hemocytes and pathogens on the heart of insects from all major branches of the class Insecta. An expanded analysis in the holometabolous mosquito, Aedes aegypti, and the hemimetabolous bed bug, Cimex lectularius, showed that infection induces the aggregation of phagocytic hemocytes on the hearts of distantly related insects, with aggregations mirroring the patterns of hemolymph flow. Therefore, the functional integration of the immune and circulatory systems is conserved across the insect tree of life.

哺乳动物的免疫系统和循环系统在功能上是整合的，例如脾脏和淋巴结的免疫功能。类似的功能整合存在于疟疾蚊子冈比亚按蚊中，例如感染诱导的心脏瓣膜周围的血细胞聚集。这是蚊子特有的还是昆虫的一般特征仍然未知。我们分析了代表 16 个目的 51 个科的 68 个物种，发现感染会诱导昆虫纲所有主要分支的昆虫心脏上的血细胞和病原体聚集。对全代谢蚊子Aedes aegypti和半代谢臭虫Cimex lectularius的扩展分析，表明感染诱导远亲昆虫心脏上的吞噬性血细胞聚集，聚集反映了血淋巴流动的模式。因此，免疫系统和循环系统的功能整合在整个昆虫生命树中得到了保护。