Fire Ant Biology: Life in the Mound

1. Workers Reproductives Egg Larvae Pupa Adult Queen 1 The fire ant has 4 life stages 8 Mature colonies consist of a range of workers made up basically of two castes, a few majors and a large number of minors. Reproductives are produced during mating season. During the summer minors live 60-90 days, majors 90-150 days. Queens can live up to seven years. 2 The circle above highlights eggs found in the brood chamber of a mound. Eggs usually take 7-10 days to hatch. Fire Ant Biology: Life in the Mound Solar Radiation Lateral foraging tunnel Exit / Entrance Reproductive 3 Larvae molt four times over a 12-15 day period. The first three instars are fed regurgitated liquid food. 1st instar 2nd instar 3rd instar 4th instar Worker Lateral foraging tunnel Interconnected Chambers 4 The fourth instar is the only stage of fire ant able to feed on and digest solid food. The food is placed in a food basket just beneath the mouth (black arrow). Deep Tunnels Ants move the brood within the mound in response to changes in the ideal environmental conditions influenced by solar radiation 7 Pupae usually turn darker as they mature. Newly emerged adults are light in color and referred to as callows. 6 Pupae that will develop into different size workers. Pupae take 9-16 days to develop. 5 Larval instars that will develop into different size workers. Compiled by Fudd Graham and Vicky Bertagnolli Adapted from: Vinson, S. B. 1997. Invasion of the red imported fire ant. Amer. Entomol. 43: 23-42.