Maeno Koutaro Ould, Ould Babah Ebbe Mohamed Abdallahi
Japan International Research Center for Agricultural Sciences (JIRCAS), Livestock and Environment Division, Ohwashi 1-1, Tsukuba, Ibaraki 305-8686, Japan.
The Mauritanian Desert Locust Centre: Centre National de Lutte Antiacridienne (CNLA), Nouakchott, BP 665, Mauritania.
Insects. 2018 Aug 13;9(3):99. doi: 10.3390/insects9030099.
Animals often aggregate at certain sites during vulnerable periods such as night-roosting as an anti-predatory strategy. Some migratory gregarious animals must regularly find new night-roosting sites, but how they synchronously choose such sites is poorly understood. We examined how gregarious nymphs of the desert locust, Forskål (Orthoptera: Acrididae), aggregate at certain plants for night-roosting in the Sahara Desert. Migratory bands of last instar nymphs climbed trees around dusk and roosted there overnight. A spatial autocorrelation analysis of plants indicated that the larger locust groups formed at the larger plants within the local plant community. Other large groups were not formed near the large tree, but smaller groups were patchily distributed. Plant height was the primary cue used by migratory bands to choose night-roosting plants. A nearest-neighbor distance analysis showed that single conspicuous large trees with scattered smaller plants were distributed locally. This plant community structure and negative geotactic ascending behavior of gregarious nymphs may force them to concentrate at the landmark plant from all directions and afar. This plant-size-dependent roosting site choice may contribute for developing artificial trapping systems for locusts and inciting to a new environment-friendly night control approach.
动物在诸如夜间栖息等易受攻击的时期，常常会聚集在某些地点，以此作为一种反捕食策略。一些迁徙性群居动物必须定期找到新的夜间栖息地点，但它们如何同步选择这些地点却鲜为人知。我们研究了沙漠蝗虫（学名：Schistocerca gregaria Forskål，直翅目：蝗科）的群居若虫是如何在撒哈拉沙漠的某些植物上聚集进行夜间栖息的。末龄若虫的迁徙群体在黄昏时分爬上树木，并在那里过夜。对植物进行的空间自相关分析表明，在当地植物群落中，较大的蝗虫群体形成于较大的植物周围。大树附近没有形成其他大群体，但较小的群体呈斑块状分布。植物高度是迁徙群体选择夜间栖息植物时使用的主要线索。最近邻距离分析表明，显眼的单棵大树与散落的较小植物在当地分布。这种植物群落结构以及群居若虫的负趋地性向上行为可能会迫使它们从各个方向和远处集中到地标性植物上。这种依赖植物大小的栖息地点选择可能有助于开发蝗虫人工诱捕系统，并催生一种新的环保夜间防治方法。
