Cocoa farmers in Palolo sub-district conducted cocoa cultivation by implementing three cocoa cropping systems, including the cocoa cropping system without using shade trees (A1), using a number of permanent shade trees (A2), and using natural forests as the shade trees (A3). The aim of the study was to determine the diversity of arthropods and decreased seed weight in the three cocoa cultivation systems. The sampling of arthropods used pitfall traps, light trap, and Yellow Fan Trap. The found 2684 arthropod individuals represented 12 orders, 47 families and 106 species. Diversity index and abundance index were the highest for cocoa crop ecosystem A2 (2.9 and 13.1). The largest decrease in weight of cocoa seeds was found in the A1 locations (8.34%) and the lowest in the A3 locations (3.61%). We recommend that cocoa cultivation should use protective trees.