Random choice of the tropical fire ant in the enclosed space

The tropical fire ant Solenopsis geminata is an invasive ant species in Taiwan. In the present study, we investigated the turning behaviour of the tropical fire ant in the T-maze when external cues were shielded. In total, 1800 observations (600 workers × 3 choices) were conducted in the study. Workers presented eight types of left-right choice after three choices in the T-maze experiment. We demonstrated that the turning behaviour of S. geminata workers was not significantly affected by the four cardinal directions. Moreover, eight types of left-right choice of workers were divided into four groups. The result shows that the ratio of the four groups is 1.33:3.27:3.25:1 (≈1:3:3:1). Notably, based on the binomial expansion, the left-right choice of workers is random. The workers' choices did not exhibit a leftward or rightward turning bias after three choices in the experiment. Thus, we speculate that in the absence visual cues, S. geminata workers might navigate using random choice strategies when exploring the enclosed space.