The Impacts of Post‐Dispersal Seed and Seedling Predation by Armadillidium vulgare (Isopod: Armadillidiidae) on Eleusine indica and Lolium multiflorum Populations

Pill bugs feed on weed seeds and seedlings; however, this interaction is rarely explored, and its effects on the weed growth and development of seedlings remain unclear. Therefore, in this study, we investigated the impacts of seed and seedling predation by the pill bug Armadillidium vulgare on Eleusine indica and Lolium multiflorum , two common weeds growing in tea ( Camellia sinensis ) fields in Shizuoka Prefecture, Japan. We compared the two treatment groups (without and with pill bugs [104 individuals/m 2 ]) in planters placed in an experimental field during summer and autumn, using a completely randomized design; each treatment had three replicates. The results revealed that A. vulgare decreased the emergence of E. indica and L. multiflorum seedlings through seed and seedling predation and affected seedling growth and development. Although the experimental design did not allow us to distinguish the effects of seed versus seedling predation, our results indicate that the pre‐germination and early germination stages represent a critical period during which predation strongly suppresses weed emergence. These findings provide initial evidence of the potential role of A. vulgare as a biological weed control agent.