广聚萤叶甲成虫产卵行为及其产卵部位的选择性

【目的】明确广聚萤叶甲成虫产卵行为及其产卵部位的选择性。【方法】在室内条件下,对广聚萤叶甲成虫交配及产卵的系列行为、产卵场所选择、不同部位豚草植株叶片叶绿素b的含量进行了观察和测定:(1)将1对成虫放到养虫笼内的一株豚草上,观察交配时间,记录产卵数量、前后2粒卵之间的产卵时间间隔;(2)在均匀分为5部分(0～10、11～20、21～30、31～40和41～50 cm)的豚草植株上,随机放置10对成虫,观察雌虫对于产卵场所的选择。(3)将上述5个部位的豚草叶片通过丙酮匀浆法处理,用紫外分光光度计测定其在645和663 nm的吸光值,计算叶绿素b含量。【结果】广聚萤叶甲成虫完成一次成功交配平均需96.09 min。雌虫一般需45 min的时间来寻找其适应的产卵场所,在产卵过程中,成虫习惯将卵产于叶片背面,雌虫喜欢用口器来清理刚产下的卵粒。在一株50 cm高的豚草植株上,雌虫喜欢将卵产在植株中部21～30 cm和中上部31～40cm的叶片上(从下往上划分)。卵块数量和豚草不同部位叶片叶绿素b含量呈显著的正相关性。【结论】广聚萤叶甲成虫喜欢产卵在叶绿素b含量较高的叶片背面,可能以视觉识别叶片颜色来选择和定位产卵场所。

Oviposition behavior and site selection of Ophraella communa adults

Aim] The selectivity of sites for laying eggs by Ophraella communa females was studied.Method] Under the laboratory conditions, the mating and egg deposition behaviors, including the choice of oviposition sites and the content of chlorophyll b in leaves of A. artemisiifolia were recorded. To do so, a pair of adults were placed on a common ragweed plant in a rearing cage and the mating duration, the number of eggs laid, and the time interval between the laying of two eggs were recorded. In addition, 10 pairs of adults were randomly placed on a common ragweed plant which were marked in five sections (0~10, 11~20, 21~30, 31~40 and 41~50 cm) in a cage, the site selection of the female to lay her eggs was recorded, and this experiment was replicated five times. Once completed, to calculate the content of chlorophyll b, the leaves of common ragweed from the five sections were treated with acetone homogenate method, and light absorption values were determined by ultraviolet spectrophotometer at 645 nm and 663 nm.Result] The average mating time was 96.09 min. It took on average 45 minutes for a female to find a suitable place to lay eggs. In the process of laying eggs, females preferred laying eggs on the back of the common ragweed leaves. and used her mouthparts to clean each newly laid egg. In a 50 cm tall common ragweed plant, females preferred to lay their eggs at the height of 21~30 cm or 31~40 cm. There was a significant positive correlation between the number of eggs and the content of chlorophyll b in a given section of the plant.Conclusion] Females of O. communa prefer laying eggs on the back of leaves with high chlorophyll b content, and may use visual recognition of leaf color to select and locate egg deposition sites.