Locusts are able to migrate over long distances across areas with different vegetation structures. This work investigates how the spatial arrangement of vegetation might affect locust collective motion. The behavior of groups of third instar Schistocerca gregaria hoppers that had been fed or starved for 24 h was studied experimentally. Food patches were introduced into a circular arena where locust groups were marching. We tested two different types of food distribution: uniform and clustered. The starved locust groups were used to simulate how encountering vegetation affected locusts after crossing a large bare area. We analyzed the directed motion and mean speed of the locust groups. On the small scale of the arena, the results did not show any effects of vegetation distribution on the oriented motion and mean speed of the groups (fed group). However, encountering vegetation greatly affected the oriented movement and walking speed in the starved group, mimicking the crossing of a large bare area (group starved for 24 h). After feeding, the individuals entered a post-prandial period. That period was significantly longer for the starved hoppers than for the fed hoppers. After the post-prandial period, the hoppers started marching and did not return to feed on the food. It is therefore suggested that the marching activity of hoppers is not directly related to their hunger level. The effect of the spatial distribution of vegetation on the hunger status of hoppers and the implication for barrier treatments used in locust control are further discussed.

中文翻译：

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饥饿和植被分布对蝗虫集体运动的影响

蝗虫能够在不同植被结构的地区进行长距离迁徙。这项工作研究了植被的空间排列如何影响蝗虫的集体运动。实验研究了喂食或饥饿 24 小时后的三龄 Schistocerca gregaria 料斗群的行为。食物补丁被引入蝗虫群行进的圆形竞技场。我们测试了两种不同类型的食物分布：均匀分布和集群分布。饥饿的蝗虫群被用来模拟穿越大片裸露区域后遇到植被如何影响蝗虫。我们分析了蝗群的定向运动和平均速度。在小规模的竞技场上，结果没有显示植被分布对各组（进食组）的定向运动和平均速度有任何影响。然而，遇到植被极大地影响了饥饿组的定向运动和步行速度，模拟了穿越大片裸露区域（组饥饿 24 小时）。进食后，个体进入餐后时期。饥饿料斗的这段时间明显长于进料料斗。餐后时期后，料斗开始行进，不再返回以食物为食。因此，建议跳跃者的行进活动与其饥饿程度没有直接关系。进一步讨论了植被空间分布对蝗虫饥饿状态的影响以及用于蝗虫控制的屏障处理的意义。模仿穿越大面积裸露区域（组饿了 24 小时）。进食后，个体进入餐后时期。饥饿料斗的这段时间明显长于进料料斗。餐后时期后，料斗开始行进，不再返回以食物为食。因此，建议跳跃者的行进活动与其饥饿程度没有直接关系。进一步讨论了植被空间分布对蝗虫饥饿状态的影响以及用于蝗虫控制的屏障处理的意义。模仿穿越大面积裸露区域（组饿了 24 小时）。进食后，个体进入餐后时期。饥饿料斗的这段时间明显长于进料料斗。餐后时期后，料斗开始行进，不再返回以食物为食。因此，建议跳跃者的行进活动与其饥饿程度没有直接关系。进一步讨论了植被空间分布对蝗虫饥饿状态的影响以及用于蝗虫控制的屏障处理的意义。料斗开始行进，并没有回来以食物为食。因此，建议跳跃者的行进活动与其饥饿程度没有直接关系。进一步讨论了植被空间分布对蝗虫饥饿状态的影响以及用于蝗虫控制的屏障处理的意义。料斗开始行进，并没有回来以食物为食。因此，建议跳跃者的行进活动与其饥饿程度没有直接关系。进一步讨论了植被空间分布对蝗虫饥饿状态的影响以及用于蝗虫控制的屏障处理的意义。