广聚萤叶甲幼虫取食植物对产卵选择行为的影响

Effects of Larval Feeding Plants on Oviposition Selection in Ophraella communa(Coleoptera: Chrysomelidae)

产卵选择性是衡量植食性昆虫寄主专一性的主要性状之一。为揭示广聚萤叶甲幼虫取食的植物是否影响其成虫产卵植物选择性，于室外网室中采用重复观测设计开展试验，研究幼虫期取食靶标豚草或非靶标苍耳对成虫在这2种植物上的产卵选择性。在非选择性试验中，广聚萤叶甲幼虫取食豚草和苍耳后的产卵数量没有显著差异；但成虫在2种植物上的产卵数量存在显著差异，如幼虫分别在豚草和苍耳上取食，其成虫在豚草上分别产18.94和21.90粒卵，而在苍耳上分别产24.39和25.12粒卵。对卵粒大小（用体积表示）的分析表明，产卵植物之间及其与幼虫取食植物互作对卵粒大小均无显著影响，但幼虫取食不同植物的成虫所产卵粒大小存在显著差异，幼虫取食豚草的成虫产卵粒显著大于取食苍耳的产卵粒。卵孵化率为60%～70%，在各处理之间没有显著差异。在选择性试验中，对产卵选择频次的分析未发现幼虫取食不同植物以及成虫产卵测试植物等处理影响产卵选择偏好。本研究结果说明，广聚萤叶甲雌成虫产卵数量决策行为受幼虫取食植物的影响不大。

Oviposition selection of plants is a critical trait in evaluation of host specificity in classical biological weed control. The non-native leafbeetle Ophraella communa （LeSage）, an oligophagous insect and effective biological control agent of the alien invasive common ragweed Ambrosia artemisiifolia L. in China, can occasionally feed the non-target cocklebur Xanthium sibiricum Patr. The effects of larval food plants A. artemisiifolia and X. sibiricum on adult selection of oviposition plants were assessed using a repeated measure design in outdoor slat house. In the no-choice trial, when oviposition plant was the same as larval food plant, the number of eggs deposited was not significantly different, but when the larvae were fed on A. artemisiifolia or X. sibiricum, more eggs were deposited on X. sibiricum than on A. artemisiifolia, averaging 24.39 and 25.12 eggs on X. sibiricum, and 18.94 and 21.90 eggs on A. artemisiifolia. Egg size （measured as volume） showed no significant difference between oviposition plants, but was significantly different between larval food plants, being bigger when larvae were fed on A. artemisiifolia than on X. sibiricum. There was no significant difference in egg hatching rate between larval food plants or between oviposition plants, ranging from 60%to 70%. In choice trials, there were no significant effects of larval food plants on oviposition plant preferences in adults. The results of this study suggested that larval food plants may have little influence on oviposition plant＆amp;nbsp;selection and number of eggs deposited.