锯叶裂臀瓢虫雌虫产卵和取食对寄主植物叶片的选择性

Oviposition and feeding preferences of adult females of Henosepilachna pusillanima(Coleoptera: Coccinellidae) for the leaves of different host plants

【目的】锯叶裂臀瓢虫Henosepilachna pusillanima (Mulsant)是瓜类蔬菜主要害虫之一,其成虫和幼虫取食前常常划圈。本研究旨在了解雌虫对南瓜Cucurbita moschata Duchesne、黄瓜Cucumis sativus L.和棱角丝瓜Luffa acutangula (L.) Roxb.叶片的行为选择。【方法】在(26±1)℃、相对湿度60%±5%、光周期L∶D=14∶10条件下,每株保留5张叶片(从生长点往下分别为第1-5位叶),接入1头已饥饿24 h怀卵雌虫。24 h后,检查每片叶正面和反面上的卵数,并测量划圈面积和取食面积,然后计算雌虫对叶片表面和不同叶位叶片的产卵选择百分率、划圈选择百分率和取食选择百分率。【结果】锯叶裂臀瓢虫雌虫仅在所划出的圈内取食,单日划圈面积和单日取食面积均以南瓜上的最小。雌虫对叶片表面的产卵选择性随瓜类植物种类而异,但划圈和取食时均喜欢选择叶片反面。雌虫不喜欢在第1叶和第2叶的叶片上产卵。雌虫的划圈和取食最喜欢南瓜和棱角丝瓜的第2叶和第3叶,但对黄瓜不同叶位的叶片没有偏好性。【结论】锯叶裂臀瓢虫雌虫产卵不喜欢太幼嫩的叶片,而划圈和取食偏好于瓜叶的反面。

[Objectives] To evaluate the oviposition and feeding preferences of adult female Henosepilachna pusillanima(Mulsant)(Coleoptera: Coccinellidae), an economic pest of cucurbitaceous vegetables, for the leaves of squash(Cucurbita moschata), cucumber(Cucumis sativus), and ridged gourd(Luffa acutangula).[Methods] Adults and larvae of H.pusillanima often exhibit trenching behavior prior to feeding on leaves. Under laboratory conditions of(26±1)℃, 60%±5%RH and a photoperiod of 14 L: 10 D, one 24-h-starved gravid female was exposed to the top five leaves of a plant counted basipetally from the growing point. After 24 hours, the number of eggs, the trenched area and the feeding area, were determined on the adaxial and abaxial surfaces of each leaf. Oviposition, trenching, and feeding preferences for different leaves and leaf surfaces were recorded.[Results] Adult female H. pusillanima fed exclusively within trenches cut by themselves on leaves. Among the three cucurbitaceous vegetables tested, both the total daily trenched area and feeding area per female were smallest on squash. The oviposition preferences for abaxial or adaxial leaf surfaces varied depending on host plant species, but females strongly preferred the abaxial leaf surfaces on all three host plants fir trenching or foraging. Females did not prefer 1 st and 2 nd leaves for oviposition. Although females preferred the 2 nd and 3 rd leaves of both squash and ridged gourd for trenching and foraging, they did not have any clear preference for specific leaves on cucumber.[Conclusion] Adult females did not prefer young leaves for oviposition, and preferred abaxial leaf surfaces for trenching and feeding.