Dissertation Research: Inter-individual Variation in Production of an Insect Defensive Secretion: Implications for Defense and Mate Acquisition

橡胶蚱蜢可以从它的食物中摄取有毒的化学物质（包括除草剂）并储存在它的体内。这些被隔离的化学物质的组成和数量取决于单个蚱蜢的内部生理能力。这些排泄能力和分泌物的组成在个体之间差别很大。这种生理变化可以通过分离蚱蜢肠道的部分来表征。此外，当受到捕食者的攻击时，蚱蜢会分泌有毒的化学物质作为威慑。PI可以使用收集的分泌物和活蚂蚁进行实验，以测试特定分泌物样本的防御功效。这为我们提供了一个系统来研究动物与其他生物相互作用中的内部生理变化的作用。橡胶蚱蜢从它们的食物中吸收的化学物质之一是常见的除草剂2,4-二氯苯酚（2,4- d）。这种除草剂在商业上以放射性形式存在，使其在防御分泌物中相对容易检测和测量。pi可以测量单个蚱蜢分泌物中2,4- d的含量，然后测试每种分泌物样本对蚂蚁的相对威慑水平。因此，我们不仅可以测量2,4- d摄取的内部生理变化，还可以表征这种变化在生态相互作用中的作用。

Spring 9701082 The lubber grasshopper can take noxious chemicals (including herbicides) from its diet and store them in its body. The composition and quantities of these sequestered chemicals depends on the internal, physiological capabilities of an individual grasshopper. These qequestrative abilities, and the compositions of secretions, vary greatly among individuals. This physiological variation can be characterized by isolating segments of the grasshopper gut. Further, when attacked by predators, the grasshoppers secrete the noxious chemicals as a deterrent. The PI can perform experiments using collected secretion and live ants to test the defensive efficacy of specific secretion samples. This provides us with a system to examine the role of internal, physiological variations on an animal's interactions with other organisms. One of the chemicals that lubber grasshoppers sequester from their diet is the common herbicide 2,4-dichlorophenol (2,4-D). This herbicide is commercially available in radioactive form, making it relatively easy to detect and measure in the defensive secretion. The PIs can measure the amount of 2,4-D in the secretion of individual grasshoppers, and then test the relative level of ant deterrence for each secretion sample. Thus, we can not only measure the internal, physiological variation in the uptake of 2,4-D but also characterize the role of that variation in ecological interactions.