Plant damages caused by belowground herbivores may be different depending on plant parts fed by them. They are known to prefer specific plant parts, and their feeding sites would depend on their distribution in the soil. Therefore, the difference in their vertical distribution is hypothesized to cause different damages on a plant.

A seedling of Lolium perenne and the 3rd instars larva of Anomala cuprea as a belowground herbivore were grown in a pot. The soil in the pot was vertically divided into three layers by wire-mesh screens that confined distributions of the larva. There were five treatments; the herbivore existing in the top layer (T1), in the middle layer (T2), and in the bottom layer (T3), the lack of the herbivore (T4), and the lack of the confines to restrict the herbivore from moving (T5).

In the T1 and T5 treatments, 7 of 9 plants died after the introducing of the herbivore while, in other treatments, mortality was not observed. The log rank test revealed significant differences of survival time of plants between treatments. The mean biomass was smaller under the existence of the herbivore in shallow layers.

Plant mortality might be caused by the severeness between a shoot and roots. This suggests that the herbivore in a shallow layer would bite off shoots and cause severe, often fatal damages on the plant.