A preliminary investigation of the effect of mole cricket (Gryllotalpa unispina Saussure; Orthoptera: Gryllotalpidae) activity on soil evaporation in semiarid Loess Plateau of northwest China

Many insect species, especially soil-inhabiting ones, greatly affect the physical and chemical properties of soil. The widespread soil-inhabiting mole cricket on the northern Loess Plateau creates subterranean tunnels, damages topsoil structures, and likely alters soil infiltration, erosion, and evaporation. In this study, we assessed the effect of adult and immature mole crickets (Gryllotalpa unispina Saussure; Orthoptera: Gryllotalpidae) on soil water evaporation in loam soil. A series of simulation experiments was conducted in iron buckets (20 cm in diameter and 20 cm high) filled with disturbed soil at the Shenmu Erosion and Environment Research Station. The soil was saturated and drained until the water content approached the field moisture capacity (25.3%), and then the soil was subjected to evaporation for 58 days. Evaporation was found to occur in two stages. In the first 18 days, daily evaporation in soil with adult and immature mole crickets was significantly (P < 0.05) lower than that in soil without mole cricket. Compared with bare soil treatment, the cumulative evaporation of soil treated with adult and immature mole crickets decreased by 24.6% and 13.9%, respectively. In the second stage, daily evaporation in soil treated with mole cricket was greater than that in bare soil due to the higher soil moisture in treatments with mole cricket in the first stage. Under the condition of continuous drought, mole cricket activity had a lag effect on soil water evaporation. The effects of mole cricket activity on soil evaporation depended on the soil-surface disturbance area, i.e., a larger disturbance area corresponded to more greatly reduced soil-evaporation function. These results can help elucidate the effects of soil-inhabiting insects on water movement in semiarid areas.