Plant density is a key factor in regulating pest and disease epidemics. According to the resource concentration hypothesis plant density will positively affect density of insects and pathogens.
With increasing planting density, microclimate alters, movement between plants becomes easier and plant defenses may be lowered because of increased investment in competition. A qualitative scoring of papers publishing the effects of plant density on the abundance of phytophagous insects showed a positive affect of plant density on host abundance in only ~34% of the studies (Rhainds & English-Loeb, 2003). Others reported as positive effect in ~57% of the studies.
As the effect of plant density on pest abundance can be both positive and negative, a better understanding is needed to what determines the relationship between host density and pest abundance. A better understanding on the relative contribution of factors that contribute to disease epidemics as a function of host density is crucial in both managed and natural ecosystems.
Types of work
In this thesis project you will do a quantitative review of the literature (meta-analysis) to investigate the overall relationship between plant density and disease prevalence, and to try uncover factors that affect this relationship. This involves a lot of reading, data, statistics and fun.
I am looking for a motivated student that is interested in this relevant topic, and likes to do a theoretical study using literature and statistics.