外来广聚萤叶甲对豚草取食和利用效率的测定

对入侵杂草豚草的天敌昆虫——外来广聚萤叶甲幼虫取食豚草不同部位叶片后的存活情况进行了观察；对不同日龄幼虫和成虫的生长速率和食物利用效率进行了测定。幼虫取食上部叶片的累计死亡率显著高于下部叶片，但与中部叶片无显著差异。广聚萤叶甲幼虫鲜重在6日龄前成倍增长，之后趋于平稳；各日龄幼虫的近似消化率均很高（〉80％），并随幼虫龄期增大而逐渐降低，但到10日龄时又有所升高；幼虫对食物的转化率与近似消化率之间未表现出常见的反比关系；幼虫取食的相对表现（相对生长率、相对取食率和相对代谢率）呈现早期高于晚期的变化格局。初羽化成虫（4d内）的取食量明显较高，之后基本保持平稳。

Consumption and Utilization of Alien Invasive Weed, Ambrosia artemisiifolia by the Alien Ragweed Leafbeetle Ophraella communa (Coleoptera: Chrysomelidae)

The survivorship the ragweed leafbeetle,Ophraella communa,larvae feeding on different leaves(representing the extent of tenderness) of the alien invasive weed,Ambrosia artemisiifolia,was observed.Consumption and utilization of larvae and adults at different ages were measured.The accumulative mortality of larvae feeding on lower leaves on the stem was significantly higher than that on top leaves but not different from that on middle leaves.Larval fresh weights doubled on each two-day prior to 6 d old and then leveled off.The approximate digestibility(AD) was markedly high(>80%) through all larval stages,gradually declined with age until 10 d old,when it increased slightly.The common inverse relationship between AD and the efficiency of conversion of digested food(ECD) was not detected.Relative rates,such as relative consumption rate(RCR),relative growth rate(RGR) and relative metabolic rate(RMR),were higher for young larvae than for old larvae.Adults within 4 d of emergence consumed much more than older adults and after 4 d,consumption rate stabilized.