七星瓢虫的种内捕食行为

Intraspecific predation behavior of Coccinella septempunctata

为了提高生防生产中七星瓢虫的存活率与利用率,达到更好的生物防治效果,以实验室自繁的七星瓢虫为研究对象,采用每日蚜虫单次饲喂和两次饲喂(间隔7小时)两种模式,对七星瓢虫的种内捕食行为进行研究。在单次饲喂试验中,七星瓢虫在二龄与三龄期未发生种内捕食现象,但在四龄期发生了种内捕食行为,其捕食发生率为38.8%,其原因为单次饲喂无法满足四龄期幼虫的食物需求量。在两次饲喂试验中,同龄七星瓢虫在各龄期均未发生种内捕食行为。本研究表明,同龄七星瓢虫在足量饲喂蚜虫条件下不会发生同类捕食行为,为七星瓢虫在规模化生产应用中的食物供应提供了重要指导。

In order to improve the survival and utilization rate of Coccinella septempunctata in biological control and production,and to achieve a better biological control effect,we investigated the intraspecific predation behavior of C.septempunctata based on two feeding modes:(i)feeding aphids only once per day,and(ii)feeding aphids twice per day with an interval of 7 h.In the scenario of feeding mode(i),no intraspecific predation was observed for both second and third instar larvae of C.septempunctata.However,intraspecific predation occurred at fourth instar,and 38.8%of the larvae were consumed,which was likely induced by the insufficient aphid supply with feeding mode(i).By contrast,no intraspecific predation was observed in feeding mode(ii).Herein the results indicate that C.septempunctata at the same instar tend to prey on aphids rather than each other when aphid supply is sufficient.Our findings have provided a substantial guide for the food supply of C.septempunctata in large-scale production.