Ants 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
