Burrows Matthew, Morawo Tolulope, Fadamiro Henry
Department of Entomology and Plant Pathology, 301 Funchess Hall, Auburn University, Auburn, AL 36849 (
New Address: Division of Parasitic Diseases and Malaria-Entomology, Centers for Disease Control and Prevention, 1600 Clifton Rd., Atlanta, GA 30329.
J Econ Entomol. 2017 Jun 1;110(3):971-977. doi: 10.1093/jee/tox048.
Parasitoids utilize various sugar resources in nature, and rely on odor cues from plants to locate their food and hosts. However, lack of sugar in the diet may negatively impact odor reception in parasitoids, thus affecting foraging efficiency. We used Microplitis croceipes (Cresson) (Hymenoptera: Braconidae), a larval endoparasitoid of Heliothis virescens (F.) (Lepidoptera: Noctuidae), as a model species to test the hypothesis that variation in sugar diet of parasitoids affects their olfactory response to host-related odors. Heliothis virescens is a major pest of cotton and other important crops. Response of female M. croceipes fed different diet treatments (i.e., 40%, 20%, 10%, or 0% sucrose/water solution [w/v]) to select cotton volatiles were tested in electroantennogram (EAG) and Y-tube olfactometer bioassays. The following cotton plant odors were tested: cis-3-hexenol, α-pinene, 50/50 v/v binary mixture of cis-3-hexenol and α-pinene, and H. virescens-infested cotton. Sucrose-fed parasitoids showed higher EAG response to the binary mixture and host-infested plant volatile extract, compared with sucrose-starved (0% sucrose) parasitoids. However, there was no significant difference in EAG response of parasitoids to odor treatments among individuals fed 40%, 20%, or 10% sucrose. In a Y-tube olfactometer, female M. croceipes fed 40% sucrose were significantly more attracted to host-infested cotton than to a control (no plant). However, parasitoids were not significantly attracted to other odor stimuli. These results suggest that the availability of sugar diet affects odor reception in M. croceipes but variation in sugar concentration probably plays a minimal role in olfactory response of M. croceipes to host-related odors.
寄生蜂在自然界中利用各种糖分资源，并依靠来自植物的气味线索来定位食物和宿主。然而，饮食中缺乏糖可能会对寄生蜂的气味接收产生负面影响，从而影响觅食效率。我们以微红绒茧蜂（Microplitis croceipes (Cresson)，膜翅目：茧蜂科）作为模式物种进行研究，它是烟芽夜蛾（Heliothis virescens (F.)，鳞翅目：夜蛾科）幼虫的内寄生蜂，以验证寄生蜂糖饮食的变化会影响其对宿主相关气味的嗅觉反应这一假设。烟芽夜蛾是棉花和其他重要作物的主要害虫。在触角电位（EAG）和Y型嗅觉仪生物测定中，测试了取食不同饮食处理（即40%、20%、10%或0%蔗糖/水溶液 [w/v]）的雌性微红绒茧蜂对棉花挥发物的选择反应。测试了以下棉花植株气味：顺-3-己烯醇、α-蒎烯、顺-3-己烯醇和α-蒎烯的50/50 v/v二元混合物，以及被烟芽夜蛾侵染的棉花。与未取食蔗糖（0%蔗糖）的寄生蜂相比，取食蔗糖的寄生蜂对二元混合物和被宿主侵染的植物挥发物提取物表现出更高的EAG反应。然而，取食40%、20%或10%蔗糖的个体之间，寄生蜂对气味处理的EAG反应没有显著差异。在Y型嗅觉仪中，取食40%蔗糖的雌性微红绒茧蜂被被宿主侵染的棉花吸引的程度显著高于被对照（无植物）吸引的程度。然而，寄生蜂对其他气味刺激没有显著反应。这些结果表明，糖饮食的可获得性会影响微红绒茧蜂的气味接收，但糖浓度的变化可能在微红绒茧蜂对宿主相关气味的嗅觉反应中起最小作用。
