暗翅筒天牛的生物学特性及空间格局

暗翅筒天牛在四川和重庆1年发生1代，以老熟幼虫越冬。成虫发生于4月下旬至7月上旬，补充营养取食桑树等植物的叶脉，产卵于桑树等植物的新梢端部，卵期为8d，孵化的幼虫依靠蛀食桑树枝条获得营养，先向上蛀食产卵槽上部的枝条，至一定距离后再调头向下蛀食产卵槽以下的枝条，且在向下蛀食过程中多次调头向上蛀食侧枝，幼虫期长达180d，至翌年4月化蛹，蛹期为16d。在幼虫期常有污翅姬蜂寄生于体内，其寄生率达37．1％。卵的空间格局呈负二项分布。

Biological Properties and Spatial Pattern of Oberes fuscipennis

An Oberes fuscipennis (Chevrolat) usually completes a life cycle within one year in Sichuan province and Chongqing, southwest China. It spends the whole winter in a form of ripe larva. Thereafter the larva of O. fuscipennis develops to its adult stage. This stage lasts relatively shorter than its larva stage, from the late April ( ca 20 April) to the early July ( ca 10 July), with imagines taking the veins of mulberry and other plant leaves as food/nutrition sources, and laying eggs on the tips of mulberry. The spatial pattern of the eggs shows a negative binomial distribution. The eggs are hatched for eight days and then the new larvae start to eat upwards the young tip of the mulberry leaves near the groove where the eggs were laid and hatched. A short while later, the larvae eat the mulberry leaves downwards for the availability of their food. Often, the larvae also turns upwards to eat the side branches, indicating that they intend to finish up the food source nearby before moving further. The larva stage is the longest period of its life. It can be as long as about ten months towards the next April when it pupates. The pupa stage lasts about 16 days. During this stage the Spilopteron sp. starts to parasitize the larvae of O. fuscipennis , and the rate of the parasitism can reach up to 37.1 % of the larvae before they start another life cycle.