Impact of Rainfall on the Nesting Activity of Solenopsis invcta in South China

摘要

Through field observations we found that workers of Solenopsis invcta would make prompt repair to the nest after the rainfall as the exits were often blocked with soils in the rain. Therefore, after each rain, the mounds were significantly higher but no significant change was found in diameter. The growth of the mound volume has a very close relationship with the rainfall and its duration. The longer the rain lasted, the greater the rainfall was, the greater the nest volume grew. The results showed that the volume of mounds was not changing constantly during the year, and it was quite different in different seasons. In November each year, the fire ants grew less active as the temperature decreased, and in the following December to February, the number of fire ant nests remained at a very low level. When April began, many new nests appeared as the temperatures rose and the rainfall increased. From May to July, it rained, and some extinct and new mounds appeared at the same time. The total number of active mounds increased significantly. Between August and October, when the temperature was relatively stable with not much rain, the mound number was maintained at a stable level.