Abstract: Solenopsis invicta is one of the most devastative invasive pests. In order to clarify the correlation between the numbers of different S. invicta instars on nest surface layer and ant mound size, 180 nests from six sites in Panyu, Guangzhou were investigated by digging method. The results demonstrated that in terms of mound volume, 57.78% of the nests were less than 5000 cm³, 20.56% between 5000 and 10000 cm³, and 21.67% greater than 10000 cm³. In terms of mound surface layer base area, 32.78% of the nests were less than 500 cm², 42.78% between 500 and 1000 cm², 24.44% and greater than 1000 cm². For an area of 1 cm² mound layer base and a volume of 1 cm³ mound, there were 3 and 22 ants, respectively. The number of each instar and total population increased with the increase of mound volume and mound surface base area. The positive correlations of the number of worker ants with the mound volume and the mound surface layer base area were more obvious than that of any other instars of S. invicta. The correlation of the amount of S. invicta with the mound volume was better than that with the mound surface layer base area.

Key words: strain LGY06, degradation characteristics, degradation pathway, Bacillus cereus, napropamide