Fire Ant

Solenopsis Invicta

Red Imported Fire Ant, RIFA (Solenopsis invicta)

  • Color: Reddish-brown - black
  • Worker size: 1/8 - 1/4 inches
  • Colony size: 100,000 - 500,000
  • Queen: 6 - 8 millimetres, claustral/parasitic, monogyne

Introduction

Leafcutter Ants are a fascinating species of insect. Leafcutters range from 1.5 mm to 12 mm. A leafcutter nest can house up to 8 million ants, and with very interesting social structures, too. Minims are the smallest workers. Their job is mainly to tend to the fungal gardens. Next are the minors, who defend the pheromone trail and are the first line of defence. Next are the leafcutter mediae, which are medium-sized workers. They usually collect leaves and forage around. Second lastly, there are majors. They primarily act as soldiers and also move heavy items. One very interesting worker caste in the Atta cephalotes hierarchy is that they have super-majors. These are huge soldiers that are much bigger than majors. The queen is around 30 mm in length.

Unique Traits

Fungal Diet

These ants have something remarkably different that sets them apart from other ants: they harvest leaves. They cut leaves with specialized mandibles from grasses, weeds, and trees and return them to their nest. These mandibles are strengthened with different metals to reduce wear. They then feed these leaves to the fungus from the genus Lepiotaceae, a special type of fungus that eats leaves. This fungus is entirely dependent on Leafcutter Ants for survival because only some species grow out in the wild. However, it does take a lot of effort to harvest these fungi, and ants carry antibiotics that detoxify the waste and protect their crops.

Defences

Leafcutter Ants have ants that are mainly soldiers who are called majors. These tough ants are huge, and they have strong mandibles infused with metals like zinc and manganese, making them very sharp and maintaining that sharpness. These ants also have a compound composed of calcium and magnesium on their heads, which is a material that resists enemy attacks. Army ants (specifically N. esenbeckii) are the only known species of ants able to kill a mature Leafcutter Ant colony.
It is worth noting the incredible worker caste that allows leafcutter ants to make a successful defence. For example, when a large threat comes near, mainly super-majors and majors respond. Meanwhile, when other ants attack the Leafcutter Ant nest, smaller workers respond. When Army Ants raid their nests, however, the leafcutter ants do not use their small workers, but not the big ones either. They mainly use their majors to defend.

Habitat & Diet

Leafcutter Ants are native to Latin America and the Caribbean. These ants live in the rainforest. To cut the leaves used to feed the fungus, they vibrate their sharp mandibles a thousand times to cut them off. These ants evolved to eat fungus because there are a lot of leaves in the area of their native habitat, and the fungus can turn the cellulose into nutrients that ants can eat, which makes it extremely nutrient efficient. When waste builds up in the fungal gardens, the leafcutter majors/minims will move the waste into a dedicated waste pile. Fun fact: the tropical forest is one of the most leaf-dense areas on Earth. They have an LAI (leaf area index) of 9, which means that for every 1 area of ground, there is 9 surface area of leaves.

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