Nest Recognition Chemical Cue of Social Insects and its ecological role

群居昆虫的一大特点是它们生活在一种叫做巢的庇护所里。工蚁离开巢穴去寻找食物，但总会回到巢穴。是什么因素使群居昆虫回到巢中？我们观察到一小块白蚁巢聚集了巢内的成员。将巢的氯仿提取物涂抹在滤纸上也可使巢成员聚集。我们开始分离聚集信息素。经硅胶柱层析纯化后，失去了吸引力，其中一个馏分中只存在阻捕活性。在活性组分中，我们鉴定出几种甾类化合物。制备了正品类固醇，并通过生物测定法检测了各化合物的抑制活性。结果表明，胆甾醇和谷甾醇具有与氯仿提取物相当的抑制作用。白蚁体提取物中不含胆甾醇和谷甾醇。这些物质在白蚁的肠道中产生。

One big characterisity of social insects is that they live in some kind of selter which is called nest. The worker cast member leave the nest to search food but always come back to the nest. What is the factor that makes the social insect come back to the nest. We observed that a small pieces of the termite Coptotermes formosanus nest aggregates the nest members. A chloroform extracts of the nest applied on a filter paper also aggregate the nest member. We started the isolation of the aggregation pheromone. After purification by silica gel column chromatography, the attractancy was lost and only arrestant activity was present in one of the fractions. In the active fraction, we identified several kinds of steroid compounds. We prepared the authentic steroids and the arrestant activity of each compound was checked by bioassay. As the results, cholestanon and sitostanon showed potent arrestant activity that was equivalent to the chloroform extract of the nest. The cholestanon and sitostanaon are not present in termite body extract. These substances are produced in gut of the termite.