Pugnacious ant

Systematic position: The pugnacious ant (Anoplolepis custodiens) belongs to the order Hymenoptera and the family Formicidae. Known for its aggressive behavior, this species is widely distributed throughout sub-Saharan Africa, where it has become a significant concern for both commercial agriculture and local ecosystems due to its ability to dominate habitats.

Biology and life cycle: This species is characterized by large, polygynous colonies containing multiple queens, which facilitates rapid population growth and high colony resilience. These ants are highly mobile and notoriously aggressive toward other insect species. They are active foragers, constantly patrolling their territory and aggressively defending food sources, which makes them very difficult to eradicate once established.

Crops affected: While these ants do not consume plant tissue directly, they inflict severe damage on a vast array of agricultural products. They are frequently found in orchards (citrus, deciduous fruits), vineyards, cotton fields, and sugarcane plantations. By interacting with the plants, they create an environment that promotes secondary infestation by other pests.

Nature of damage and harm: The primary agricultural harm is linked to their mutualistic relationship with honeydew-producing insects such as aphids, mealybugs, and scale insects. By protecting these sap-sucking pests from natural predators and parasitoids, the ants allow the pest populations to explode. This leads to plant stress, reduced yields, and the proliferation of sooty mold on the leaves and fruit.

Control measures: Effective management of Anoplolepis custodiens requires a multifaceted approach focused on cutting off the ants' access to their preferred hosts. Recommended practices include:

• Applying sticky bands or physical barriers on tree trunks to prevent ants from reaching the canopy.
• Using slow-acting toxic bait stations, which foraging ants carry back to the nest to eliminate the queens.
• Targeted control of honeydew-producing insects to reduce the availability of food resources.
• Careful monitoring of orchard peripheries to prevent the expansion of existing colonies.