Lek mating females away from the hotshot. A manipulative experiment using the little bustard, "Tetrax tetrax", was done to test the various lek evolution models. The experiment involved varying the size and sex ratio of leks using decoys. To test whether or not the presence of a hotshot determined lek formation, a hotshot little bustard decoy was placed within a lek. After the fake hotshot was added to the lek, both male and female visitation to the lek increased. The hotspot model considers the female density to be the catalyst for the clustering of males. This model predicts that leks will form
Ascochyta tarda Ascochyta tarda Ascochyta tarda or Phoma tarda is a fungal plant pathogen that causes dieback and leafspot on coffee and was first observed in Ethiopia in 1954 (Stewart, 1957). It poses a potentially serious threat to coffee crops, but climate change may reduce the prevalence of environmental conditions favorable to its spread. Die-back is a condition in which a tree or shrub begins to die from the tip of its leaves or roots backwards, owing to disease or an unfavorable environment). Necrosis of both flowers and rosettes is also observed with this pathogen and this can significantly reduce crop yield.