Multi-trophic interactions of Butterflies Along a gradienT of MANagement intensity in grasslands and forest (BATMAN)

在不断变化的环境中，管理强度对食草动物捕食和寄生等生态系统过程的影响研究较少。田间围隔试验是量化自下而上和自上而下控制食草动物效果的一种很好的方法。在这个项目中，我们的目标是沿着管理强度梯度量化不同捕食者群体和食用植物内生真菌对蝴蝶幼虫的相对重要性。我们进一步检测了蝴蝶及其寄生蜂的物种多样性和一种草的内生真菌感染率沿管理强度的梯度。调查将在三个探索实验室的全部300个集中研究地块(森林和草原)上进行。围栏试验将在其中一半的地块进行，部分将在非常密集的研究地块进行。在非常密集的地块上进行的第一次实验中，每个地点的封闭物对不同捕食者群体的访问方式将不同。我们假设，在管理不那么密集的研究地点，捕食者确实会更成功地控制食草动物。在第二个实验中，我们还利用内生菌感染的食用植物来操纵食用植物的质量，这些食用植物产生昆虫有毒生物碱，并将其与不含内生菌的植物进行比较。随着捕食者的灭绝，以及昆虫捕食者完全可以接触到标准化食品厂中固定数量的饲养蝴蝶幼虫，我们将沿着管理梯度量化自下而上和自上而下控制的相对重要性。我们假设，在管理强度较高的地块上，自下而上的控制变得更重要，而自上而下的控制变得不那么重要。我们将进一步量化真菌新伤寒沙门氏菌的内生真菌感染率。并将在实验室实验中测试内生菌的存在对蝴蝶幼虫生活史的影响。最后，我们将用样带数量和它们在饲养的蝴蝶幼虫中的寄生蜂多样性来量化蝴蝶的多样性。我们假设，与蝴蝶较低的营养水平相比，增加管理强度对寄生蜂多样性的负面影响更大，而且比维管束植物低得多。

The impact of management intensity on ecosystem processes like predation and parasitism of herbivores is poorly studied in changing environments. Field exclosure experiments are a good method to quantify effects of bottom up and top down control of herbivores. In this project we aim to quantify the relative importance of different predator groups and endophytic fungi in food plants on butterfly larvae along a management intensity gradient. We further detect the species diversity of butterflies and their parasitoids and of the endophyte infection rate of one grass species along the management intensity gradient. The surveys will be conducted on all 300 intensive study plots (forest and grasslands) in the three exploratories. The exclosure experiments will be conducted in half of these plots and partly in the very intensive research plots. In a first experiment on the very intensive plots exclosures on each site will differ in their access for different predator groups. We hypothesize that predators do control herbivores more successfully in less intensively managed study sites. In a second experiment we also manipulate the food plant quality by using endophyte infected food plants, which produce insect toxic alkaloids, and compare it with endophyte free plants. With predator exclosures and full access of insect predators to a fixed number of reared butterfly larvae on the standardized food plants we will quantify the relative importance of bottom up and top down control along a management gradient. We hypothesize that bottom up control becomes more important and top down control less important on plots with higher management intensity. We will further quantify endophyte infection rates with the fungi Neotyphodium sp. of a grass species and will test the effects of endophyte presence on the life history of butterfly larvae in laboratory experiments. Finally we will quantify the diversity of butterflies with transect counts and their parasitoid diversity in reared butterfly larvae. We hypothesize that the parasitoid diversity is more negatively affected by increasing management intensity than the lower trophic level of butterflies and much lower than vascular plants.