Phylum: Anthropoda | Class: Insecta | Order: Hymenoptera | Family: Formicidae


Economic Importance

  • Ant trails from nests to food source are a cause for concern
  • Ant infestation can cause food contamination
  • Ant bites and stings can cause allergic reaction in sensitive individuals
  • Some ants can bite and sting (for e.g. fire ants)
  • Ants can cause contamination to surgical equipments

Ant Anatomy

  • Ants have 3 main body regions - head, thorax and abdomen
  • Some ants may have one or two petiole nodes
  • Other structures like eyes, thoracic spines, gaster and nodes help in identification of different ant species
  • Ants have 3 pairs of legs

Ant Biology

  • Ants are social insects and have a caste system which includes 4 castes: workers, males, females and the queen
  • Queens are long lived, mate once, rear first brood
    • Some species are characterized by multiple queens that live only for one year. The colony produces new queens each year (Tramp ants)
  • Males are short lived and normally die after mating
  • Workers are sterile females, do all the work of the colony, care for the reproductive and immature members of the colony
  • Ants undergo complete metamorphosis

Feeding Behavior of Ants

  • For most species of ants, workers do not consume solid food
  • Workers take solids back to nest
  • Larvae are fed by trophallaxis, a process in which an ant regurgitates liquid food held in its crop, a thin-walled expanded portion of the alimentary tract used for storage of food prior to digestion
  • Liquids are then used to feed the rest of the colony
  • Food gathering,colony moving, breeding and defence against predators is highly organised and carried out as a unit which may comprise of thousands of individual ants
  • New workers spend the first few days of its adult life caring for the queen and young
  • They graduate to digging and other nest work and later to defending the nest and foraging

Ant Foraging

  • All ants are part of a social order/colony
    • Workers care for reproductive and immature members of the colony
    • Generally the older workers leave the nest to forage for food, bring it back and feed 80% of the nest
  • All reproductive and immature ants require protein which is collected by workers
    • Protein demand is highest during periods of heavy egg production (typically spring and summer months)
  • Most worker ants eat carbohydrates, generally plant sap or honeydew. Some species eat plant parts such as seeds (harvester ants), which serves as a source of carbohydrates
    • Food preferences will influence foraging patt erns and bait selection/acceptance; sweet vs fatty, liquid vs solid
    • Some ant species tend sap-sucking insects to collect honeydew
    • Feed at extrafloral and floral nectaries
    • Forage for sweets and proteins in homes
    • Feed mainly on sweets - will tend aphids and mealybugs on plants for their honeydew
    • Also forage on seeds, insects, and greasy foods
    • Some ants are likely to invade the home during rainy weather since their natural food supply, honeydew, is washed from vegetation

Ant Life Cycle

Ants are members of the order hymenoptera and undergo complete metamorphosis. The four stages are:

  • Egg
  • Larva
  • Pupa
  • Adult

Major Ant Species

Black Carpenter Ants (Camponotus spp)

  • Black carpenter ants have a dull black coloured head and body
  • They have whitish or yellowish hairs on the abdomen
  • Can cause damage to sound wood
  • Ingeneral, carpenter ants prefer wood that is moistand infested with wood decay fungi
  • Workers are most active at night

Black Crazy Ants (Paratrechina longicornis)

  • Occurs in large numbers in homes or out-of-doors
  • Ants of this species often forage long distances away from their nests
  • The crazy ant is extremely easy to identify on sight by observing its rapid and erratic movements
  • The crazy ant worker is relatively small (2.3-3 mm)
  • The head, thorax, and petiole are dark brown to blackish
  • The antennae of the crazy ant have 12-segments without a club and are extremely long
  • Black crazy ants have extremely long antennae and long legs

Ghost Ants (Tapinoma melanocephalum)

  • The ghost ants have adark head and pale or translucent legs and abdomen
  • They mainly feed on sweets but will also feed on grease and occasionally dead insects
  • The name ghost ant was coined since the legs and abdomen of the ant look transparent while the head and thorax are dark brown in color
  • They generally form colonies outside but will set up colonies indoor during dry conditions

Yellow Crazy Ants (Anoplofepis gracilipes)

  • They have a body length of approximately 4 mm, a yellow brownish color with a darker brown abdomen and remarkably long legs and antennae
  • The petiole is thick, with an inverted-U-shaped crest
  • Although they cannot sting,the ants spray formic acid in defense
  • Yellow crazy ants generally live in one colony but may also form large high density super colonies

Ant Management Program

  • Identify the right ant species
  • Seal cracks and crevices around foundations
  • Store food items like sugar, syrup, honey etc in sealed containers
  • Control methods will be aided by removing the food source or alternate host
  • Perimeter treatment provides basis for overall ant control program. A full chemical treatment consists of an insecticide application into the wall plus a perimeter spray to the exterior foundation. Apply in sufficient volume to penetrate ground cover
  • Use baits which have insecticides mixed with materials that attract ants
  • The goal is to completely wipe out the colony along with the queen. Baits contain low concentration of the insecticide so that the ants can take it back to their colony and transfer the insecticide to the members of the colony