Guangxi Key Laboratory of Agric-Environment and Agric-Products Safety, College of Agriculture, Guangxi University, Nanning, Guangxi, Peoples R China.
Texas A&M AgriLife Research Center, Beaumont, Texas, United States of America.
PLoS One. 2020 Oct 30;15(10):e0241115. doi: 10.1371/journal.pone.0241115. eCollection 2020.
Allotraeus asiaticus Schwarzer and Callidiellum villosulum Fairmaire are repeatedly intercepted in wood and wood products all over the world. As two common stem borers of Cunninghamia lanceolata (Lambert) Hooker, to further understanding of the differences in their living habits, behaviors and the mechanism of insect-host chemical communication, we observed the external morphology, number and distribution of antennal sensilla of A. asiaticus and C. villosulum with scanning electron microscopy (SEM), respectively. The results showed that 1st-5th subsegments of the flagellum are spined endoapically in A. asiaticus which is different from the previous report (1st-3rd of the flagellomere). Meanwhile, there were five subsegments on the flagellum of C. villosulum that were clearly specialized as serrated shapes on the 4th-8th flagellomeres. Four types (ten subtypes) of sensilla were both found on the antennae of these two fir longhorn beetles, named Böhm bristle (Bb), sensilla trichodea (ST I and II), sensilla basiconica (SB I, II and III), sensilla chaetica (SCh I, II, III and IV). There is one additional kind of morphological type of sensilla found on the antennae of C. villosulum compared to A. asiaticus which was related to their habit of laying eggs only on dry and injured fir branches, named sensilla campaniformia (SCa). These differences may vary according to their own biological habits. For research purposes, the observed difference in the sensillum distribution and function between the two fir longhorn beetles will greatly facilitate the design of better semiochemical control methods of these insect pests.
亚洲南洋杉天牛和绒毛卷叶象是在世界各地的木材和木制品中被反复截获的两种常见的杉天牛。作为杉木（Cunninghamia lanceolata (Lambert) Hooker）的两种常见蛀干害虫，为了进一步了解它们在生活习性、行为以及昆虫与宿主化学通讯机制方面的差异，我们分别利用扫描电子显微镜（SEM）观察了亚洲南洋杉天牛和绒毛卷叶象触角的外部形态、感器的数量和分布。结果表明，亚洲南洋杉天牛触角鞭节 1-5 亚节内卷有刺，这与之前的报道（鞭节 1-3 亚节内卷有刺）不同。同时，绒毛卷叶象触角鞭节有 5 个亚节明显特化为锯齿状，位于第 4-8 鞭节上。这两种冷杉长角象甲的触角上都发现了 4 种（10 个亚型）感器，分别命名为 Böhm 鬃毛（Bb）、感觉毛（ST I 和 II）、感觉锥（SB I、II 和 III）和感觉刺（SCh I、II、III 和 IV）。与亚洲南洋杉天牛相比，绒毛卷叶象的触角上还发现了一种额外的形态类型的感器，与它们只在干燥和受伤的冷杉枝条上产卵的习性有关，命名为钟形感器（SCa）。这些差异可能因自身的生物习性而有所不同。对于研究目的而言，观察到这两种冷杉长角象甲之间在感器分布和功能上的差异，将极大地促进这些害虫半化学控制方法的设计。
