Movement, Distribution, and Survival of Cyrtomenus bergi (Hemiptera: Cydnidae) within the Soil Profile in Experimentally Simulated Horizontal and Vertical Soil Water Gradients

Movements, distribution, and survival of Cyrtomenus bergi Froeschner were investigated in experimental vertical and horizontal soil moisture gradients. Soil moisture acted as an important guide for movement, and the insects were attracted to moist soil. In the horizontal soil moisture gradient, most insects remained at soil moisture levels far beyond field capacity, but emigrated at moisture levels below the wilting point. In vertical soil moisture gradients, C. bergi showed positive geotaxy when the top soil was moist. Conversely, emigration was induced in dry top soil even with favorable soil moisture below. High relative air humidity stimulated activity above the ground. C. bergi was generally found closer to the soil surface in the morning than in the afternoon, especially during the dry season. High relative humidity induced flight regardless of the soil moisture level.