广聚萤叶甲成虫取食经历对后续 产卵寄主选择的影响

【背景】取食经历对植食性昆虫的寄主选择行为具有较大影响,影响天敌昆虫寄主专一性测定的设计和结果解释。【方法】采用选择性试验,观察了入侵豚草的重要天敌——广聚萤叶甲成虫羽化后取食不同植物对其后续产卵寄主选择的影响。【结果】与取食豚草的试虫相比,有取食三裂叶豚草、苍耳或菊芋经历的成虫选择苍耳产卵的频次增加,不再对豚草表现出明显的选择偏好性。对产卵识别期的Cox模型分析结果表明,成虫早期取食不同植物,对后续产卵选择有显著影响,成虫羽化后如果先取食豚草或三裂叶豚草,则选择苍耳产卵的倾向显著低于豚草;但如果先取食苍耳、菊芋和农家向日葵,则选择苍耳产卵的倾向与豚草无显著差异。【结论与意义】由此推测,广聚萤叶甲初羽化成虫取食的植物对其后续产卵选择具有较大影响,因而在寄主专一性测定中应关注测试前饲喂的植物种类。

Effects of early feeding experience on oviposition host selection in Ophraella communa(Coleoptera:Chrysomelidae)

Background]Experience has influence on host selection behavior in herbivorous insects,which can affect host specificity testing design and the explanation of the results.Method]Multiple choice trials were performed on the exotic lepidopteran,Ophraella communa,an important biological control agent of the invasive common ragweed,Ambrosia artemisiifolia,to evaluate how previous feeding experiences during early adulthood influenced subsequent oviposition choices.Result]Adults after emergence with prior feeding experience on non-target plants,A.trifida,Xanthium sibiricum or Helianthus tuberosus increased oviposition on X.sibiricum,while not on the target weed,A.artemisiifolia.The analyses using Cox regression model of recognition time to oviposition indicated that prior feeding experience on different plant species had significant influence on oviposition choices for the respective plants they experienced.The tendency of oviposition on X.sibiricum was significantly lower compared to that on A.artemisiifolia when the adults had a feeding experience on A.artemisiifolia or A.trifida,but not different when the insects had such experience on X.sibiricum,H.tuberosus,or H.annuus.Conclusion and significance]Feeding experiences on plants early at adult stage can influence ensuing oviposition host selection.Therefore,caution should be exercised in routine host-specificity test when dealing with feeding test insects prior to the testing.