Ants and Ant ControlAnts and Ant Control

Dr. Richard M. Houseman

Department of Entomology

University of Missouri

Ants

• Order Hymenoptera– More than 8,800 species world-

wide

• Social Insects– Division of labor

• Complete metamorphosis• Complex Feeding

– Feed on many different things– Circulate food within the

colony

Social Organization

• Life Stages– Eggs

• Fertilized or unfertilized

– Larvae• Legless, grub-like stage

• Cannot feed themselves

• Perform no maintenance

• Digest solid materials

– Pupae• Inactive, pre-adult stage

Social Organization

• Life Stages– Worker

• Sterile adult females

• Most numerous stage in colony

• Responsible for all nest maintenance activities

– Reproductives• Queen = egg production; single or multiple queens

• King = winged; only for mating and dies afterward

Ant Biology

• Feeding and Nutrition– Eat many different kinds of food

• Honeydew, Sweets• Protein, Oil • Seeds, Plants • Insects

– Usually have preferred food types

Feeding and Nutrition

• Workers obtain solid and liquid food– Honeydew preferred

– Aphids protected by many ants

• Trophollaxis – Solid foods digested by larvae

– Digested food circulated through the colony by workers

Ant Biology

• Nesting Habits– Nesting sites usually chosen

by instinct

– Three Nest Types• Soil nests

• Wood nests

• Opportunistic nests

– Knowing nesting habits is important

Missouri Ants

• Hundreds of species– Not all considered pests.

• Several pest ants present

• Most belong to one of three groups– Myrmecinae – Formicinae– Dolichoderinae

Ant Management

• Identify the ant.

• Find out where the queen ant is living.

• Direct control measures at areas where the queen is living.

• Correct contributing conditions

Missouri’s Top Ten

– Little black ant– Pharaoh ant*– Acrobat ant– Pavement ant– Carpenter ant*– Yellow ant– Cornfield ant– Allegheny Mound ant*– Odorous house ant*– Argentine ant

Pest Ant Identification

• Three Main Characters• Antennae

– All ants have elbowed antennae

• Waist– Pedicel with node(s)

• Anus– Nozzle or slit-like– With or without hairs

Pest Ant Identification

• Myrmecinae – Pedicel with two nodes

• Formicinae– Pedicel with one node

– Anal hairs

• Dolichoderinae– Pedicel with one node

– No anal hairs

Missouri Myrmecinae

• Little Black Ant– Opportunistic, budding

• Pharaoh Ant– Opportunistic, budding– Multiple, related queens– Supercolonies

• Acrobat Ant– Wood nests, single queen

• Pavement Ant– Soil nest, many queens

together

Missouri Formicinae• Carpenter Ant

– Even thorax, multiple size workers, wood nests, single queen

– Satellite colonies

• Yellow Ant– single queen; soil nest

• Cornfield Ant– single queen; soil nest

• Allegheny Mound Ant– Uneven thorax, Multiple size

workers; soil nests; multiple queens

Allegheny Ant Mound (Formica exsectoides)

Myrmecinae

• Imported fire ant (Solenopsis invicta)

– 10S Antennae; 2S club– Honeydew, sweets, protein, oil,

seeds, plants, insects– Workers multiple sizes– Single or multiple queens– Soil Nests

• Open, sunny areas; crater-shaped mound; under debris; inside logs;

– Swarms spring through summer; colony budding

Missouri Dolichoderinae

• Odorous House Ant– Small; one size; opportunistic

– Single queen; no swarm

• Argentine Ant– Small; one size; opportunistic

– Multiple, related queens; no swarm

Ant Management

• Identify the ant.

• Find out where the queen ant is living.

• Direct control measures at areas where the queen is living.

• Correct contributing conditions

Ant Management

• Possible Control Tactics– Physical and Cultural– Chemical

• Directed at queen– Mound drenches– Void spaces– Wood treatments– Baits

• Directed at structure– Perimeter treatments

Ant Management

• Cultural– Sanitation

• Remove food sources

• Remove nesting sites– Debris piles

– Vegetation

• Moisture control– Ventilation

Ant Management

• Physical– Exclusion

• Sealing cracks and crevices– Often very difficult due to size

– Vacuuming• Useful for removing exposed

satellite colonies

Ant Management

• Chemical (Queen-directed)– Soil Drenches

• Soil-dwelling ants– Apply to mound, mulch, etc.

• Thorough penetration– Low-pressure spray

– Watering can

– Best for single queen ants

Ant Management

• Chemical (Queen-directed)– Void Treatments

• Wall voids– Nests usually found at base of wall

• Brick veneer– Apply at weep holes along outside

• Masonry brick/hollow blocks– Drill near infestation and inject insecticide

– Dusts and aerosols commonly used

Ant Management

• Chemical (Queen-directed)– Wood treatment– Injection

• Drill into nest

• Dusts or aerosols

Ant Management

• Chemical (Queen-directed)– Baits

• Depend on species and colony (‘finicky eaters’)• Sweet vs. protein feeders and yearly cycles

– Try several different types until get good feeding

– Placed near to the colony• Use lots of bait in untreated areas• In corners and along active trails• Check within a week

Ant Management

• Chemical (Structure-directed)– Perimeter Treatments– Used to prevent workers from entering the structure

• Temporary relief

• Applied to base of foundation and area adjacent to foundation

– Wettable powders, microencapsulated

Ant Summary

• Social Insects• Different forms in colony; division of labor

• Many pest species in Missouri• Unique in appearance and biology; identification is

key to control

• Interesting Biology• Communicate using chemical signals• Food sharing within colony• Variety of nesting habits and feeding preferences