Changes in the movement patterns of adult Stethorus parapauperculus in response to starvation
Author of the article:CHEN Jun-Yu1** MA Hua-Bo2 ZHANG Fang-Ping1 HAN Dong-Yin1 FU Yue-Guan1***
Author's Workplace：1. Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; 2. College of Environment and Plant Protection, Hainan University, Haikou 570228, China
Key Words：Stethorus parapauperculus, movement pattern, track ArcGIS
Abstract：
[Objectives] To analyze changes in the movement patterns of starved and replete Stethorus parapauperculus in 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 of S. parapauperculus fed on T. 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 of S. parapauperculus subject to different levels of starvation were analyzed comparatively, and prey searching behaviors characterized. [Results] Starved and replete S. parapauperculus needed (5.99+-0.91) and (2.25+-58) mins, respectively, to consume a single spider mite head. The starved S. parapauperculus usually 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, starved S. parapauperculus frequently turned around, and their turn angles were larger. The trajectory of S. parapauperculus was mainly distributed around prey. Pre and postfeeding search distances and speeds of S. parapauperculus were significantly different. The search trajectory of replete S. parapauperculus fluctuated markedly between pre and postfeeding with no clear pattern. The curved length between track points and search speeds was not significantly different between pre and postfeeding. [Conclusion] The prey searching behavior of S. parapauperculus is influenced by hunger. Starved S. 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 postfeeding prey searching behavior of replete S. parapauperculus with both extensive and localized searching tending to occur random.