Yang Xinya, Li Guangsheng, Wang Cai
College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
Insects. 2024 Sep 26;15(10):746. doi: 10.3390/insects15100746.
(Lepidoptera: Crambidae) is a severe pest of plants, which produce high-priced agarwood. The larval stage of this pest is gregarious, usually forming large aggregates during young instars and becoming solitary during the fifth instar. We hypothesize that the cuticle chemicals of young-instar larvae could promote larval aggregating, whereas the cuticle chemicals of late-instar larvae would no longer attract young-instar larvae. In this study, two-choice tests were conducted to evaluate the effect of cuticle extracts of second- and fifth-instar larvae on the aggregation preference of second-instar larvae. Results show that significantly more larvae aggregated on the leaves treated with the hexane extract of second-instar larvae than on untreated leaves. However, the hexane extract of fifth-instar larvae had no significant effect on the aggregation preference of the second-instar conspecific larvae. Interestingly, acetone extracts of both second- and fifth-instar larvae repelled the second-instar conspecific larvae throughout the 8 h experiment. Our study shows that cuticle chemicals of larvae may play a role in the group dynamics of this pest, which may contribute to screening novel attractants and repellents for . Detailed chemical analyses of the extracts and identification of the compounds involved in larval attracting and repelling would be valuable in future studies.
（鳞翅目：草螟科）是一种严重危害能产生高价沉香的植物的害虫。这种害虫的幼虫阶段具有群居性，通常在低龄幼虫期形成大的群体，而在五龄幼虫期变为独居。我们推测，低龄幼虫的表皮化学物质可能促进幼虫聚集，而高龄幼虫的表皮化学物质不再吸引低龄幼虫。在本研究中，进行了双选试验，以评估二龄和五龄幼虫的表皮提取物对二龄幼虫聚集偏好的影响。结果表明，与未处理的叶片相比，更多的幼虫聚集在经二龄幼虫正己烷提取物处理的叶片上。然而，五龄幼虫的正己烷提取物对二龄同种幼虫的聚集偏好没有显著影响。有趣的是，在整个8小时的实验中，二龄和五龄幼虫的丙酮提取物都排斥二龄同种幼虫。我们的研究表明，幼虫的表皮化学物质可能在这种害虫的群体动态中起作用，这可能有助于筛选新的引诱剂和驱避剂。对提取物进行详细的化学分析以及鉴定参与幼虫吸引和排斥的化合物在未来的研究中将是有价值的。
