The Effects of Temperature on the Foraging Activity of Red Imported Fire Ant Workers (Hymenoptera: Formicidae) in South China

Yong Yue Lu

doi:10.13102/sociobiology.v59i2.619

Abstract

In this study, we investigated the effects of temperature of the ambient air, ground surface, and the soil at 5-cm deep on the foraging activity of the workers of red imported fire ant, Solenopsis invicta Buren, in South China with the method of bait traps. Significant correlations were observed between the temperature and the foraging activity of fire ants. Specifically, when the ambient temperature was above 20 °C, the fire ants foraged actively, and the activity reached a maximum when the ambient temperature was between 25 to 33 °C. But the foraging activity decreased as the ambient temperature rose higher than 34 °C. Moreover, fire ants were found to forage at maximal rates with the soil surface temperature between 27 to 40 °C. The ants started foraging when the soil temperature at 5-cm deep was between 16 to 48 °C, while 28~37 °C was the optimal temperature for the foraging activity. The extreme temperature thresholds for foraging of the ambient air, soil-surface, and soil at 5-cm deep were 11 °C/44 °C, 10 °C/57 °C, and 12 °C/48 °C respectively.

Highlights

The red imported fire ant, Solenopsis invicta, is an important invasive species
The number of workers captured indicated that the foraging was active when the ambient temperature, the soil surface temperature, and the soil temperature at 5-cm deep were above 20 °C, 22
The foraging of S. invicta worker ants was noted when the soil temperature at 5-cm deep was from 12 to 48 °C, and when the ground surface temperature was between 10 and 57 °C. This suggests that the minimum foraging temperature for S. invicta worker ants is lower in China than that in Florida, USA (Porter & Tschinkel 1987), where the low soil temperature at 2-cm deep was 15 °C

Summary

Introduction

The red imported fire ant, Solenopsis invicta, is an important invasive species. It originated from South America and was introduced into the United Sates of America (USA) in 1930s (Vazquez et al 2003). Fire ants inhabit about 129.5 million ha. In South USA and Puerto Rico (Williams et al 2003). It was estimated that fire ants caused more than $1-billion of economic loss each year in the southern states of USA (Wojcik et al 2001). In China, this pest was first detected on September 28, 2004

Methods

Results

Conclusion