禾谷缢管蚜复眼外部形态的扫描电镜观察

External morphology of the compound eye of Rhopalosiphum padi (Hemiptera: Aphididae) observed using scanning electron microscopy

【目的】通过比较禾谷缢管蚜Rhopalosiphum padi两种生活史(全周期型和不全周期型)及5种蚜型(有翅孤雌蚜、无翅孤雌蚜、雄蚜、雌性蚜和产雌性母)成蚜复眼外部形态,分析了其视觉能力差异,为进一步探索禾谷缢管蚜生殖转换及寄主搜寻机制提供参考。【方法】利用扫描电镜技术,观察全周期型和不全周期型禾谷缢管蚜无翅孤雌蚜及其低温短日照(12℃,光周期8L∶16D)诱导条件下全周期型所产5种蚜型成蚜的复眼外部形态。【结果】禾谷缢管蚜成蚜复眼着生于头部触角基部,呈卵圆形,小眼间无感觉毛。全周期型和不全周期型禾谷缢管蚜无翅孤雌蚜的复眼大小(长轴直径及短轴直径)、复眼弧高、小眼数量和小眼直径均没有显著差异。而这5个复眼指标在低温短日照诱导全周期型禾谷缢管蚜产生的5种蚜型的成蚜中均存在显著性差异,其中,雄蚜、有翅孤雌蚜和产雌性母的复眼区域较大,小眼数量较多;雌性蚜的复眼区域最小,小眼数量也最少。【结论】综合以上指标结果,推测5种蚜型的视觉能力由大到小是:雄蚜>有翅孤雌蚜>产雌性母>无翅孤雌蚜>雌性蚜。复眼和小眼的这些差异可能与禾谷缢管蚜生殖转换及寄主搜寻存在一定的联系。

【Aim】This study aims to analyze the difference in the visual ability of Rhopalosiphum padi adults by comparing the external morphology of compound eyes of five different forms(winged virginoparae,wingless virginoparae,male,oviparae and gynoparae)and wingless virginoparaes from holocyclic and anholocyclic life cycles,so as to provide a basis for further exploring the reproductive transformation and host searching mechanism of R.padi.【Methods】The external morphology and types of compound eyes in holocyclic and anholocyclic wingless virginoparae of R.padi and adults of five forms produced by the holocyclic aphids at low temperature(12℃)and short photoperiod(8L∶16D)were observed using scanning electron microscopy(SEM).【Results】The compound eye of adult R.padi is oval and located at the base of antenna in the head,without sensory hairs in the separation of ammatidias.There is no significant difference in the size(long axis diameter and short axis diameter)and arc height of compound eyes,the amount of ommatidia and the diameter of ommatidium between holocyclic and anholocyclic wingless virginoparae of R.padi.However,there are significant differences in the size and arc height of compound eyes,the amount of ommatidia,and the diameter of ommatidium among the five forms of R.padi with holocyclic life cycle at low temperature and short photoperiod.Male,winged virginoparae and gynoparae have larger compound eye area and a larger number of ommatidia than wingless virginoparae and oviparae,and oviparae has the smallest compound eye area and the lowest number of ommatidia.【Conclusion】Combining the results of the five parameters,it was assumed that the visual ability of the five forms of R.padi from strong to weak is as below:male,winged virginoparae,gynoparae,wingless virginoparae and oviparae.The variances in compound eyes and ocelli might be associated with reproductive transformation and host searching of R.padi.