Insects in several orders deposit marking pheromones following oviposition. In addition to preventing the female from visiting the same site again, the pheromone also signals the presence of eggs to conspecific females. This form of chemical marking is particularly prevalent in species which oviposit on discrete hosts with limited resources available for developing larvae. The pepper weevil is a major pest of cultivated pepper throughout the southern United States, Mexico and the Caribbean. The weevil deposits eggs singly in a cavity chewed in flower buds and small fruits and caps these cavities with a plug derived from an anal secretion. The deterrent was found to be located in this oviposition plug and comprised of volatile and contact-acting components. Plug volatiles were collected by inducing oviposition into Teflon tape sachets containing pepper leaves and collecting volatiles from plugs laid on the tape surface. Of the two major components observed by GC/MS analyses, only acetophenone elicited a behavioral response by the female weevil in small arena and wind tunnel assays. Investigations of the oviposition plug matrix identified several free unsaturated and saturated fatty acids as major constituents of the plug which was in stark contrast to pepper tissue and seeds that contained only trace levels of free fatty acids and a distinctly different total fatty acid composition. The combined free fatty acids as well as acetophenone tested singly gave no significant reduction in oviposition while a plug-mimicking blend of unsaturated fatty acids tested in combination with acetophenone as artificial ‘plug spots,’ decreased oviposition on treated peppers by up to 75%. We propose that the combination of volatile and contact acting marking components improves oviposition site selection efficiency by pepper weevils on discrete hosts.

产卵后，昆虫会分几个顺序沉积标记信息素。除了阻止雌性再次访问同一部位外，信息素还向同种雌性发出卵子的信号。这种形式的化学标记尤其在产于幼虫的资源有限的不连续宿主上产卵的物种中尤为普遍。胡椒象鼻虫是整个美国南部，墨西哥和加勒比海地区栽培胡椒的主要害虫。象鼻虫将卵单独沉积在咀嚼着花蕾和小果实的腔中，并用源自肛门分泌物的塞子堵塞这些腔。发现该威慑剂位于该产卵塞中，由挥发性和接触作用成分组成。通过诱使产卵到含有胡椒叶的特氟龙胶带袋中并从放置在胶带表面上的塞子中收集挥发物来收集塞子挥发物。在GC / MS分析中观察到的两个主要成分中，只有苯乙酮会在小型竞技场和风洞试验中引起雌性象鼻虫的行为反应。产卵栓塞基质的研究确定了几种游离的不饱和脂肪酸和饱和脂肪酸是该栓塞的主要成分，这与仅含微量游离脂肪酸和明显不同的总脂肪酸组成的胡椒组织和种子形成了鲜明的对比。单独测试的组合的游离脂肪酸和苯乙酮的产卵率没有明显降低，而与苯乙酮组合作为人工“塞点”测试的不饱和脂肪酸的塞状模仿混合物，使经处理的辣椒的产卵率降低了75％。我们建议挥发性和接触作用的标记成分的组合通过不连续的宿主上的胡椒象鼻提高产卵位点的选择效率。