Mo Carmen, Smilanich Angela M
Department of Biology, University of Nevada, Reno, NV, United States.
Ecology, Evolution, and Conservation Biology Graduate Program, University of Nevada, Reno, NV, United States.
Front Physiol. 2023 Feb 24;14:1127670. doi: 10.3389/fphys.2023.1127670. eCollection 2023.
Exotic plant species represent a novel resource for invertebrates and many herbivorous insects have incorporated exotic plants into their diet. Using a new host plant can have physiological repercussions for these herbivores that may be beneficial or detrimental. In this study, we compared how using an exotic native host plant affected the immune system response and feeding efficiency of a specialist lepidopteran, the common buckeye (: Nymphalidae, Hübner 1822). In a lab experiment, larvae were reared on either the exotic host plant, (Plantaginaceae), or the native host plant, (Phrymaceae). Beginning at second instar feeding efficiency data were collected every 2 days until fifth instar when immune assays were performed. Immune assays consisted of standing phenoloxidase activity, total phenoloxidase activity, and melanization. Interestingly, we found that all three immune system parameters were higher on the exotic host plant compared to the native host plant. The exotic host plant also supported higher pupal weights, faster development time, greater consumption, and more efficient approximate digestibility. In contrast, the native host plant supported higher efficiency of conversion of ingested and digested food. The relationship between immunity and feeding efficiency was more complex but showed a large positive effect of greater host plant consumption on all immune parameters, particularly for the exotic host plant. While not as strong, the efficiency of conversion of digested food tended to show a negative effect on the three immune parameters. Overall, the exotic host plant proved to be beneficial for this specialist insect with regard to immunity and many of the feeding efficiency parameters and continued use of this host plant is predicted for populations already using it.
外来植物物种是无脊椎动物的一种新资源，许多植食性昆虫已将外来植物纳入其食谱。使用新的寄主植物可能会对这些食草动物产生生理影响，这种影响可能是有益的，也可能是有害的。在本研究中，我们比较了使用外来本地寄主植物如何影响一种特化鳞翅目昆虫——常见的七叶树蝶（Junonia coenia，蛱蝶科，许布纳，1822年）的免疫系统反应和取食效率。在一项实验室实验中，幼虫分别用外来寄主植物车前叶山罗花（Plantaginaceae）或本地寄主植物小米草（Phrymaceae）饲养。从二龄开始，每2天收集一次取食效率数据，直到五龄时进行免疫测定。免疫测定包括静置酚氧化酶活性、总酚氧化酶活性和黑化作用。有趣的是，我们发现与本地寄主植物相比，外来寄主植物上的所有三个免疫系统参数都更高。外来寄主植物还支持更高的蛹重、更快的发育时间、更大的食量和更高的近似消化率。相比之下，本地寄主植物支持更高的摄入和消化食物转化率。免疫与取食效率之间的关系更为复杂，但寄主植物摄入量增加对所有免疫参数都有很大的正向影响，特别是对于外来寄主植物。虽然影响不那么强烈，但消化食物的转化率往往对这三个免疫参数有负面影响。总体而言，外来寄主植物在免疫和许多取食效率参数方面对这种特化昆虫有益，预计已经使用这种寄主植物的种群会继续使用它。
