Abstract: In 2006, daily and seasonal outing activities of the worker ants and nuptial flights of alates in the red imported fire ant, Solenopsis invicta Buren, were investigated in Guangzhou area （113°45′E, 22°43′N） of Southern China. The results indicated that daily outing activity of worker ants differed greatly among different seasons or months. Number of worker ants peaked around the midday from December to February but in the morning and afternoon from April to November. Annually, the number of outing worker ants encountered peaked in June and October and reached the lowest in January and February. Period of worker ants encountered outside the nests from April to November was significantly longer than that from December to March. The outing activity of worker ants was greatly enhanced by showers in comparison with that in fine day. However, activity of worker ants was held back during raining. Number of worker ants encountered increased greatly and reached the highest at 30 s after their nests were disturbed. Moreover, the number of worker ants encountered was positively correlated to the degree of nest disturbed. Nuptial flights of alates took place in the experimental area all the year round, but occurred mainly from March to May. Nuptial flights of alates were enhanced before or after raining. Those results provide a reference value for understanding of the occurrence of red imported fire ant in China and enhancing its monitoring skills.

Key words: Solenopsis invicta, outing activity, seasonal dynamics, daily rhythm, aggression, nuptial flights