SEASON AND SOIL-MOISTURE EFFECT ON MOVEMENT, SURVIVAL, AND DISTRIBUTION OF CYRTOMENUS-BERGI (HEMIPTERA, CYDNIDAE) WITHIN THE SOIL-PROFILE

A field experiment was carried out to elucidate movement of the burrow er bug, Cyrtomenus bergi Froeschner, and its distribution in soil prof iles under dry and rainy season soil moisture conditions. By combinati ons of dispersal restrictions we demonstrated that flying, walking on the soil surface, and shallow burrowing were all equally important way s of dispersal for insect adults during the rainy season. During the d ry season, however, burrowing was inhibited, but flying and walking on the soil surface were significant. Nymphs dispersed by walking on the soil surface while burrowing capacity was low. Damage caused by C. be rgi feeding did not vary between the 2 seasons, and the habitat of bot h adults and nymphs remained between the surface of the soil and 20 cm below. Interaction between vertical distribution and seasons was due to low survival at 0-10 cm during the dry season. The relatively highe r abundance at 10-20 cm during the dry season was explained by low sur vival at 0-10 cm; this result contradicts previous suggestions that th e higher abundance was due to downward movements.