Pharaoh ant (Monomorium pharaonis)

Pest Snapshot - Pharaoh Ant

Scientific name: Monomorium pharaonis
Identification: Light brown / yellow with darker abdomen. Size: 1.5 – 2.0 mm. 2 nodes on petiole.
Health threat: Low (although hygiene issues in hospitals)
Bite / sting pain: Does not bite or sting
Difficulty to control: Moderate
Diet: Switch between protein and sugar
Nest locations: Indoors in wall cavities, electrical outlets and near heat sources
Colony structure: Multi-queen, multi-nest
Main pest season: Year round (indoors)
Indoor/Outdoor pest: Indoor

Pharaoh ant information

Distribution:

The origin of the Pharaoh ant is unknown. Although primarily a tropical species, it readily lives within buildings in cooler climates.

In New Zealand it is frequently found inside buildings, particularly hospitals.

Typical nest location:

Typically nests indoors in wall cavities, sub-floors, near heat sources and electrical outlets.

Colony size / structure:

Multiple queens and multiple nests as part of the same colony. Budding can create building-wide infestations, with colonies containing hundreds of thousands of ants.

Identification:

Colour: Light brown with darker abdomen
Size: 1.5 – 2.0 mm
Nodes on petiole: Two

Food preferences:

Highly varied diet (protein, oils and sugar). Known to switch between protein and carbohydrate food sources. Readily feeds on dried blood (thus the problems it can cause in hospitals).

Distinguishing features / behaviours:

Only active during the day
Can produce long-lasting trails
“Pits” in their cuticle give the head and thorax a dull appearance

Bite / sting:

Pharaoh ants do not sting / bite (humans).

Prevention tips:

Clearing up food spills, regular cleaning of the cooker and grill, and not leaving petfood out will make the area less attractive to Pharaoh ants.

Other comments:

Can sometimes be confused with the Singapore ant and big-headed ant.

Other types of ants.

How to get rid of Pharaoh ants - Treatment notes

It is highly recommended that a professional pest manager is used to get rid of pharoah ant problems. With their complex nest structure and changing feeding preferences homeowners struggle to get control, especially as they cannot access the specialist products required.

Protein based and sugar based baits used in rotation can prove quite successful in pharaoh ant control, although repeat applications may be necessary. It is very important to place the baits near the foraging trails, as they develop very persistent trails.

Non-repellent sprays can also be used to prevent ants coming inside.

The use of repellent (pyrethroid) products is not advised, as they can cause the nest to fracture and bud. As such, whereas dusts applied to electrical outlets (where they like to nest) would be a standard approach for other ants, it is generally better to use baits with Pharaoh ants.

The bottom line is that with Pharaoh ant control programs it is important to eliminate all the ants in all the nests within the building to eradicate the infestation.