FOOD AND ENERGY-REQUIREMENTS OF LABORATORY FIRE ANT COLONIES (HYMENOPTERA, FORMICIDAE)

This study was designed to determine how much food is needed to sustain colonies of the fire ant Solenopsis invicta Buren. Thirty laboratory colonies were fed 1, 2, or 4 crickets per day. Half were given access to unlimited sugar water. Colony biomass, cricket collection, and sugar collection were monitored weekly until each colony stopped growing Caloric intake was strongly correlated with and directly proportional to colony biomass (live weight) over an 8-fold range (2-16 g). Colonies needed approximate to 1.14 +/- 0.29 (Standard deviation) Kcal of food per gram of colony per week to sustain themselves. The presence of sugar decreased the amount of cricket biomass collected (dry weight) from 0.186 g/g of colony per week for colonies receiving crickets to 0.196 g/g of colony per week for colonies receiving both sugar water and crickets. Colonies fed only crickets approximately doubled their final size with the doubling of cricket availability; whereas, colonies receiving both crickets and sugar increased to a lesser extent. The laboratory food collection rates in this study suggest that a field population of fire ants with 90 mature mounds per hectare would require approximate to 21,000 Kcal or 16.0 kg of insects and sugar (combined wet weight) per week in the summer.