7A Ch7 Cheat Sheet: Ants

🎯 Top 5 Traps

1

Carpenter ants do NOT eat wood — they excavate galleries with their jaws and discard the shavings. Wood has no nutritional value to them. They feed on honeydew, other insects, ripe fruit juices, sweets, meats, and moist kitchen refuse. The discarded shavings (called "sawdust") are very soft, like those a fine chisel would make. This is a critical distinction from termites, which DO digest wood as food.

2

Pharaoh ants almost always nest INSIDE — the only common Michigan ant for which this is true. They prefer warm areas (80 to 85 degrees F) such as wall voids, cracks in woodwork, stacks of paper, bed linens, bandage packs, and desk drawers. Active year-round. Common pests of hospitals, office buildings, and laboratories.

3

Carpenter ants nesting indoors indicate a MOISTURE PROBLEM. They make their nests in wood that has been wet and infested by brown rot fungus. Dark fungus stains on wood indicate the harborage. Always investigate moisture sources first: leaking plumbing, gutter overflow, improper flashing, leaking roof valleys, unvented attics or crawl spaces, exposed window sills.

4

Pharaoh ant colonies do NOT swarm — they spread by COLONY BUDDING. One portion of the colony goes with each queen. Spraying or fogging will SPLIT the colony into multiple new colonies, making the infestation worse. New infestations also transfer when infested objects are moved between rooms or buildings. Use baits, never repellent sprays.

5

Baits take 7 to 14 days for normal colony elimination, with a SURGE in ant activity at 2 to 3 weeks from new pupae emerging. Replace baits every 3 months or less. Ants are extremely sensitive to chemical residues — never spray or fog around bait stations, and clean up prior pesticide residues with detergent and water before bait placement. Different ant species require different baits.

🔢 Numbers You Must Know

Number

What It Represents

1/4 to 1/2 inch

Black carpenter ant worker size range — large for an indoor ant

3/4 inch

Black carpenter ant queen size

1/8 inch

Worker size for acrobat, pavement, and odorous house ants

1/16 inch

Worker size for pharaoh, little black, and thief ants — the smallest indoor ants

3,000 to 4,000

Average odorous house ant colony size; multiple queens

80 to 85 degrees F

Pharaoh ant preferred nesting temperature in buildings

7 to 14 days

Normal time for baits to eliminate an ant colony

2 to 3 weeks

When a surge in ant activity may occur after baiting (new emergence from pupae) — rebait as required

every 3 months

Maximum bait replacement interval — ants are not attracted to stale baits

1 week to 10 days

Recommended reinspection interval after treatment (longer for baits and IGRs than for dusts)

3 castes

Ant social structure: workers (all female), female reproductives (queens), male reproductives. Soldiers may arise as a specialized worker subgroup in some species.

1 or 2 nodes

Number of swollen segments on the petiole (waist) — a key species ID feature. Carpenter and odorous house ants have 1 node; acrobat, pavement, pharaoh, little black, and thief ants have 2 nodes.

🔀 Easily Confused

Pair / Group

Distinguishing Feature

Ants vs Termites (swarmers)

The chapter's central distinction. Ants: narrow petiole "wasp" waist; elbowed antennae (long straight first segment); two pairs of wings of UNEQUAL size (front wider/longer); complete metamorphosis. Termites: no waist (thorax and abdomen blend); bead-like antennae; two pairs of wings of EQUAL size that break off easily; gradual metamorphosis. See full comparison table below.

Carpenter ant shavings vs Construction sawdust

Carpenter ant shavings: very soft, fine-chisel cuts, often piled below nest opening or "dumped" later. Construction sawdust: gritty, often left over from past construction or repairs in attics or on sills. Confusing similar appearance.

Carpenter ant shavings vs Acrobat ant shavings

Both are dumped from gallery excavation. Carpenter ant shavings: larger, may or may not be stained. Acrobat ant shavings: smaller AND always dark-stained from fungus.

Carpenter ant vs Field ant (outdoors)

Both can be confused outdoors. Carpenter ant: even, smooth, arching profile from behind the head down to the petiole. Field ant (Formica): bumps or spines along thorax profile, particularly near the petiole. Field ants do not enter structures.

Odorous house ant vs Little black ant

Both small and dark. Odorous house ant: 1/8 inch, ONE node (hidden by overlapping abdomen), foul odor when crushed, soft body, dark brownish gray with velvety sheen. Little black ant: 1/16 inch, TWO nodes, shiny black, normally nests outdoors.

Little black ant vs Thief ant

Both 1/16 inch with two nodes. Little black ant: shiny BLACK. Thief ant: shiny YELLOWISH or slightly darker. Thief ants nest both inside and outside; little blacks nest outdoors normally.

Pavement ant dump vs Carpenter ant sawdust

Both leave debris piles. Pavement ant dump: sand, seed coats, dead insect parts, AND construction sawdust — accumulated debris cleaned out of the colony. Carpenter ant sawdust: shavings produced by gallery excavation in wood — soft, chisel-like cuts.

Indoor colony vs Outdoor colony indicators

Inside indicators: workers found indoors over a long uninterrupted period; nest building observed inside; high-rise building infestation; inside swarming. Outside indicators: ants can be trailed from inside to outside; ants seen entering from outside; nesting sites visible outside near the structure (mounds at foundation, infested trees touching the house).

🐜 Ant Species ID Quick Reference

LARGE ANTS (1/2 inch or larger)

Species

Size / Nodes / Color

Habitat & Key Behavior

Black carpenter ant
Camponotus pennsylvanicus

Worker 1/4 to 1/2 in; queen 3/4 in; ONE node; black (with gray/yellow hairs on abdomen)

Excavates galleries in WET wood (brown rot fungus). Outdoor harborage: living trees with rotted spots, stumps, firewood. Most active at night. Indoors = moisture problem.

SMALL TO MEDIUM (1/8 to 1/2 inch)

Species

Size / Nodes / Color

Habitat & Key Behavior

Acrobat ant
Crematogaster spp.

~1/8 in; TWO nodes; shiny brown to nearly black

Points abdomen UP or over head when excited (hence the name). Lives in damp wood, sometimes in ABANDONED CARPENTER ANT GALLERIES. Tends honeydew-producing insects.

SMALL ANTS (1/8 to 1/4 inch)

Species

Size / Nodes / Color

Habitat & Key Behavior

Pavement ant
Tetramorium caespitum

~1/8 in; TWO nodes; dull red-brown head and thorax (parallel furrows), darker abdomen, lighter legs

Nests outside under rocks and pavement edges; moves colonies inside between foundation and sill plate. DUMPS debris (sand, seed coats, insect parts, construction sawdust) from foundation walls onto basement floors.

TINY ANTS (1/8 inch or less)

Species

Size / Nodes / Color

Habitat & Key Behavior

Odorous house ant
Tapinoma sessile

~1/8 in; ONE node (hidden by abdomen); dark brownish gray with velvety sheen; soft body

FOUL ODOR when crushed. Average colony 3,000 to 4,000 with several queens. Outside: tends honeydew insects, takes flower nectar. Inside: prefers sweets. One of the most difficult to control.

Pharaoh ant
Monomorium pharaonis

~1/16 in; TWO nodes; dull yellowish to light orange head and thorax; shiny dark abdomen

ALMOST ALWAYS NESTS INDOORS. Multiple queens; spreads by COLONY BUDDING (not swarming). Prefers 80-85 F. Major pest in hospitals, offices, labs. Found in IV tubes, medicine droppers, bandage stacks.

Little black ant
Monomorium minimum

~1/16 in; TWO nodes; shiny black

Normally nests OUTDOORS. Tends honeydew-producing insects. Widely distributed in northern and eastern states.

Thief ant
Solenopsis molesta

Less than 1/16 in; TWO nodes; shiny yellowish or slightly darker

Nests both INSIDE and OUTSIDE. Tends honeydew insects. Hard-to-find nests make baiting especially valuable.

🪵 Ant vs Termite Swarmer Identification

Distinguishing swarming reproductives is one of the most-tested skills for Category 7A applicators. Communicate the differences clearly to clients who fear termite damage.

Feature

Ants

Termites

Waist (petiole)

NARROW "wasp" waist between thorax and abdomen

NO narrow waist — thorax and abdomen blend together; body is straight-sided

Antennae

ELBOWED — long straight first segment; remaining segments flex and bend

Entirely FLEXIBLE — many small segments strung out like beads; waved in front to touch and feel

Wings

2 pairs UNEQUAL — front pair wider and markedly longer than back; often a black dot near tip; dark veins visible; do NOT break off easily

2 pairs EQUAL — same shape and almost the same length; veins NOT visible to naked eye; BREAK OFF with a touch

Sign of swarming

Wings remain attached

BROKEN WINGS LITTER the swarm area where termites have been crawling

Metamorphosis

COMPLETE — egg, larva, pupa, adult (all look different); workers are ADULTS

GRADUAL — egg, nymph, adult; nymphs look like adult workers; reproductives are dark-bodied

💡 Memory Hooks

Ant vs termite waist: "ANT has the waist, termite is straight." Pinch waist (petiole) = ant. Straight body = termite.

Carpenter ant motto: "Chisels, doesn't chew." Carpenter ants excavate wood with their jaws but cannot digest it. Termites chew AND digest.

Carpenter = wet wood: "Find the moisture, find the colony." Carpenter ant infestation indoors = brown rot fungus + moisture intrusion.

Pharaoh palace: "Pharaoh lives in the palace." The only common Michigan ant that almost always nests INSIDE — and the one that spreads by colony budding, not swarming.

Bait timing: "7 to 14 to kill, 2 to 3 weeks for the surge." Initial knockdown takes a week or two; expect a temporary spike from new pupae before the colony collapses.

Honeydew currency: "Aphids pay rent in honeydew." Many ants protect aphids, mealybugs, scale insects, whiteflies, and planthoppers in exchange for the sweet liquid. Outdoor honeydew control reduces indoor foraging.

Ch.7: Ants

🎯 Top 5 Traps

🔢 Numbers You Must Know

🔀 Easily Confused

🐜 Ant Species ID Quick Reference

🪵 Ant vs Termite Swarmer Identification

💡 Memory Hooks