不同饥饿程度的拟小食螨瓢虫成虫摄食朱砂叶螨前后的运动格局变化

【目的】对比分析饥饿和未饥饿的拟小食螨瓢虫Stethorus parapauperculus成虫取食朱砂叶螨Tetranychus cinnabarinus前后的运动格局变化,为探明其搜索行为的生态学机制提供参考。【方法】基于Nakamuta装置原理,跟踪并绘制拟小食螨瓢虫成虫取食前后的运动轨迹,采用ArcGIS空间分析模块对运动轨迹进行处理,获取其统计参数,对比分析该瓢虫在两种状态下取食前后的搜索距离、搜索速度、搜索角度变化等特征,并阐述其搜索行为特性。【结果】饥饿24 h和未饥饿瓢虫取食单头朱砂叶螨所需时间分别为(5.99±0.91)min和(2.25±0.58)min。饥饿24 h的瓢虫在取食前多呈直线或锐角行走,运动轨迹主要分布于试验区域近边缘处,且各停点间曲线距离、搜索速度均大于取食后;取食后掉头次数频繁,活动角度转换增大,运动轨迹主要在猎物附近区域进行搜索,且在取食后60~75 s的搜索距离、搜索速度与取食前均存在显著差异。未饥饿状态瓢虫取食前后运动轨迹角度波动较大,无明显规律,且各停点间的曲线长度、搜索速度经t检验无显著差异。【结论】拟小食螨瓢虫成虫对猎物的搜索行为受其饥饿状态的影响。饥饿状态下,取食前为广域型搜索,取食后一段时间内为地域集中型搜索;未饥饿状态下的瓢虫取食前后的搜索行为则无明显规律,其搜索类型兼有广域和地域集中型搜索特征,具有一定随机性。

Changes in the movement patterns of adult Stethorus parapauperculus in response to starvation

Objectives] To analyze changes in the movement patterns of starved and repleteStethorus parapauperculusin order to better understand the ecological mechanisms underlying the prey searching behavior of this species.Methods] Based on the Nakamuta device, we tracked and plotted the movement trajectory ofS. parapauperculusfed onT. cinnabarinus. The statistical parameters of tracked movements were obtained by spatial analysis techniques performed using ArcGIS 10.0. The searching distances, searching speeds, and changes in search angle ofS. parapauperculus subject to different levels of starvation were analyzed comparatively, and prey searching behaviors characterized.Results] Starved and repleteS. parapauperculus needed (5.99±0.91) and (2.25±0.58) mins, respectively, to consume a single spider mite head. The starvedS. parapauperculususually moved in straight lines and acute angles, the trajectory of which was concentrated on the edges of the study area. The curved distances between track points and searching speeds were higher during the pre- than during the post-feeding period. After feeding, starvedS. parapauperculusfrequently turned around, and their turn angles were larger. The trajectory ofS. parapauperculuswas mainly distributed around prey. Pre- and post-feeding search distances and speeds ofS. parapauperculuswere significantly different. The search trajectory of repleteS. parapauperculusfluctuated markedly between pre- and post-feeding with no clear pattern. The curved length between track points and search speeds was not significantly different between pre- and post-feeding.Conclusion] The prey searching behavior ofS. parapauperculus is influenced by hunger. StarvedS. parapauperculus tended to search extensively during the pre-feeding period, but concentrated their search effort in a smaller area after feeding. There was no consistent difference in the pre- and post-feeding prey searching behavior of repleteS. parapauperculus with both extensive and localized searching tending to occur random.