温度对海岛小花蝽5龄若虫捕食茶黄蓟马功能反应的影响

Effects of Temperature on the Functional Response of the Fifth Instar Orius maxidentex Ghauri Nymphs to Scirtothrips dorsalis Hood

海岛小花蝽(Orius maxidentex Ghauri)是蓟马的重要天敌昆虫,在热带地区,海岛小花蝽是优势天敌,对高温有较强的适应能力,较适合热带地区的害虫防治。目前海岛小花蝽对茶黄蓟马(Scirtothrips dorsalis Hood)的控害情况尚未明确,为了解海岛小花蝽对茶黄蓟马的控制作用,明确不同温度对海岛小花蝽捕食茶黄蓟马功能反应的影响。本研究以海岛小花蝽5龄若虫为例,在16、20、24、28、32℃温度条件下,测定海岛小花蝽5龄若虫对茶黄蓟马2龄若虫和成虫的捕食功能反应。在16~32℃,随着温度的升高,海岛小花蝽5龄若虫随猎物密度的增加,其捕食量有明显的逐级上升趋势;试验温度范围内海岛小花蝽5龄若虫对茶黄蓟马的捕食功能反应均符合HollingⅡ型方程。海岛小花蝽5龄若虫对茶黄蓟马2龄若虫的捕食能力与茶黄蓟马成虫的捕食能力并无明显差异,在28~32℃范围内,海岛小花蝽对茶黄蓟马的捕食量显著高于其他试验温度;海岛小花蝽5龄若虫在试验温度32℃,猎物密度为60头时捕食量最大,对茶黄蓟马2龄若虫与成虫的捕食量分别为34.6、34.0头。海岛小花蝽5龄若虫对茶黄蓟马2龄若虫与成虫在32℃时的处理时间最短,分别为0.0119、0.0115 d。海岛小花蝽5龄若虫对茶黄蓟马的捕食量与茶黄蓟马猎物密度呈正相关,但寻找效应与猎物密度呈负相关,在相同的猎物密度下,随着温度的升高,寻找效应逐渐下降,海岛小花蝽5龄若虫对茶黄蓟马表现出较高的寻找效应。当猎物密度大于最大捕食量时,海岛小花蝽5龄若虫取食具有选择性,仅取食茶黄蓟马腹部。海岛小花蝽5龄若虫在较高的温度条件下表现出对茶黄蓟马有良好的控害能力,是热带地区重要的天敌资源。

Orius maxidentex Ghauri is an important natural enemy insect of thrips.O.maxidente is a dominant enemy in the tropics which has strong adaptability to high temperature and more suitable for pest control in tropical areas.At present,the control of O.maxidentex to Scirtothrips dorsalis Hood is not clear.To understand the control effect of O.maxidente on the predation of S.dorsalis,it is important to clarify the effects of temperature on the predation of O.maxidentex Ghauri nymphs to S.dorsalis Hood.The study assessed the predatory function response of the fifth instar O.maxidentex to the second instar and adult S.dorsalis at 16℃,20℃,24℃,28℃ and 32℃.In the range of 16-32℃,the predation of O.maxidentex increased with the increase of the prey density.When the temperature increased,a trend of gradual increase in predation was also observed.Within the experimental temperature range,the predatory function of O.maxidentex to S.dorsalis fit to the Holling Ⅱ equation.There was no significant difference between the predation ability of the 5th instar nymphs of O.maxidentex on the 2nd instar nymphs of S.dorsalis and the adult nymphs of S.dorsalis.In the range of 28-32℃,the predation of O.maxidentex on the S.dorsalis was significantly higher than that of the other test temperature.The 5th instar nymph of O.maxidentex had the largest prey when the test temperature was 32℃,and the prey density was 60,which was 34.6 and 34.0,respectively.The instantaneous attack rates of O.maxidentex to the second instar and adult S.dorsalis were also the highest at 32℃,which was 0.0119 d and 0.0115 d,respectively.The predatory capacity of O.maxidentex on S.dorsalis was positively correlated with the prey density,whereas the searching efficiency was negatively correlated with the prey density.At the same prey density,as temperature increased,the searching efficiency gradually decreased.The fifth instar O.maxidentex showed a relatively high searching efficiency of S.dorsalis.When the prey density was greater than the maximum predation,the 5th instar nymphs of O.maxidentex had selective feeding,only feeding on the abdomen of S.dorsalis.It seems that the predatory bug O.maxidentex has good ability to control the pestiferous thrip S.dorsalis under high temperature condition and is an important natural enemy for the thrips in the tropic area.