ABSTRACT

The red mite, Oligonychus yothersi (McGregor) (Acari: Tetranychidae), is a serious foliar pest of avocado (Persea americana Mill.) orchards in Chile. In summer, avocado plants release herbivore-induced plant volatiles (HIPVs) in response to feeding behaviour of O. yothersi. These HIPVs recruit natural enemies of the red mite as Parastethorus histrio (Chazeau) (Coleoptera: Coccinellidae) and Oligota pygmaea (Solier) (Coleoptera: Staphylinidae). However, P. histrio and O. pygmaea remain in infested avocado trees throughout the summer until late autumn. Therefore, we collected HIPVs, in late autumn, to test the behavioural responses of the red mite and its coleopterans predators. Volatiles were collected under semi-field conditions using the headspace technique and Porapak Q as adsorbent. The chemical analysis revealed that infested plants emitted (Z)-β-ocimene, α-farnesene, and methyl salicylate (MeSA), increasing the emissions of R-limonene. These variations triggered an attractive behaviour in P. histrio and O. pygmaea, yet O. yothersi remained indifferent. The emitted HIPVs by avocado infested plants, in late autumn, elicited tri-trophic interactions in avocado orchards, where higher R-limonene emissions and up-regulated three new volatile compounds in the volatiles profile could have influenced predator’s choice, being necessary to examine.

摘要

红螨Oligonychus yothersi (McGregor) (Acari: Tetranychidae) 是智利鳄梨 ( Persea americana Mill.) 果园的严重叶面害虫。在夏季，鳄梨植物会释放食草动物诱导的植物挥发物 (HIPV)，以响应O. yothersi 的摄食行为。这些 HIPV 将红螨的天敌招募为Parastethorus histrio (Chazeau) (Coleoptera: Coccinellidae) 和Oligota pygmaea ( Solier ) (Coleoptera: Staphylinidae)。然而，P. histrio和O. pygmaea整个夏天都留在受侵染的鳄梨树中，直到深秋。因此，我们在深秋收集了 HIPV，以测试红螨及其鞘翅目捕食者的行为反应。使用顶空技术和 Porapak Q 作为吸附剂在半场条件下收集挥发物。化学分析表明，受感染的植物会排放 ( Z )- β-罗勒烯、α-法呢烯和水杨酸甲酯 (MeSA)，从而增加了R-柠檬烯的排放量。这些变化在P. histrio和O. pygmaea 中引发了一种有吸引力的行为，而O. yothersi仍然无动于衷。在深秋，鳄梨感染植物释放的 HIPV 引发了鳄梨果园的三营养相互作用，其中更高的R-柠檬烯排放和挥发物中三种新的挥发性化合物的上调可能影响了捕食者的选择，有必要进行检查。