Dietary preference and polymorphism of Solenopsis invicta foragers in China in summer and autumn

【Objective】 To identify the foraging habits of the red imported fire antSolenopsis invicta Buren in newly invaded region of Guangzhou, and to provide scientific basis for researching and developing new baits to control the fire ant. 【Method】 The diurnal dynamics and body polymorphism of foragers in the colony of the red imported fire ant were observed by using directly-dissecting underground foraging tunnel at mulberry orchard and barren land in summer and autumn in Guangzhou.【Result and conclusion】 The results showed that foraging rates of fire ant workers for liquid-or solid-food were significantly different in habitats and seasons, but no difference in interaction of two treatments. The foraging rates of dietary preference for liquid food in all treatments were significantly higher than those for solid food. The average proportion of workers carring liquid food in crop ［summer: (36.58±8.74)%, autumn: (37.60±5.16)%］ was significantly higher than the proportion of workers carrying solid foods ［summer: (8.03±1.66)%, autumn: (7.30±1.71)%］.Individual polymorphism of workers feeding solid food, liquid food and responsible for defense showed a continuity of skewed distribution. Their average head width were (0.652 4±0.007 1), (0.636 1±0.006 2) and (0.636 3±0.006 4) mm, respectively, showing no significant difference among them.