Periplaneta americana (Linnaeus, 1758)

American cockroach

The giant of indoor cockroaches, up to 5 cm long, living in sewers, basements and steam tunnels.

Order: Blattodea
Family: Blattidae
Group: Cockroaches
Ontario status: Established indoors (sewers, large buildings); cannot overwinter outdoors

Why it matters

Travels through sewers and decaying matter, so it can carry germs onto food-contact surfaces. Its size and sewer habit make it alarming, though it bites nothing and stings nothing.

Origin

Not from America either, likely Africa or the Middle East in origin, spread worldwide centuries ago on ships.

Behavior

Nocturnal; forages at night and glides short distances on its wings when disturbed. Often enters buildings from sewers through floor drains.

Living conditions

Loves warm, damp, dark places: sewers, storm drains, basements, boiler rooms, steam tunnels. In Ontario it lives indoors in large buildings, not in houses generally.

Signs of presence

Very large (35-50 mm) reddish-brown cockroaches, often near drains or basements
Purse-shaped egg cases (~8 mm) dropped in damp hiding spots
Musty odor in enclosed damp areas
Shed skins near sewer access points

Weaknesses

Cannot survive an Ontario winter outdoors
Needs constant moisture, dry buildings exclude it
Slow breeder compared to the German cockroach, so populations grow more slowly

Myths and facts

Myth It is called a 'palmetto bug' so it must be a different insect.
Reality 'Palmetto bug' is just a regional nickname for the American cockroach.
Myth Big cockroaches fly into your hair on purpose.
Reality They glide clumsily when startled; they are not targeting people.

Research notes

Morphology

Adults 35-50 mm, reddish-brown with a pale yellowish margin around the pronotum. Both sexes winged; males' wings extend slightly beyond the abdomen. Nymphs uniformly reddish-brown, wingless.

Diagnostics

Confirm by size (35-50 mm) + pale pronotal margin + purse-shaped ootheca dropped (not carried). Cerci prominent.

Easily confused with

Smokybrown cockroach, Validiblatta fuliginosa (syn. Periplaneta fuliginosa) Smokybrown is uniformly dark mahogany with no pale pronotal margin; American always shows the pale margin.
Oriental cockroach, Blatta orientalis Oriental is smaller (20-30 mm), darker, and females are short-winged; American females are fully winged.

Life cycle

Adult: Lifespan up to ~1 year; females produce oothecae at roughly weekly intervals in warm conditions.
Egg: Purse-shaped ootheca (~8 mm) with ~14-16 eggs, dropped or glued in moist crevices; hatches in ~50-55 days at 28 °C.
Egg to adult: 5-15 months depending on temperature, much slower than the German cockroach
Generations per year: ~1 indoors
Nymph or larva: 13 nymphal instars; development slow.

Development

Incomplete metamorphosis: egg → nymph → adult.

Reproduction

~14-16 eggs per ootheca, produced roughly weekly by each female under warm conditions.

Distribution

Global: Cosmopolitan in warm regions; indoor/sewer populations in temperate zones
Native range: Likely Africa or the Middle East
Ontario: Established indoors in large buildings, sewers and institutions; cannot overwinter outdoors

Ecology

Peridomestic and sewer-dwelling; strongly associated with decaying organic matter, sewers, storm drains and steam tunnels. Glides rather than sustained flight. Aggregates in warm, humid refugia.

Resistance

Pyrethroid resistance (kdr mutations, metabolic mechanisms) documented in some populations; less intensively studied than the German cockroach.

IPM implications

Monitoring targets below-grade and utility areas: floor drains, sump pits, sewer access, boiler rooms. Because it immigrates from sewers, exclusion (drain covers, sealed penetrations) is as important as interior monitoring. Slow development means populations respond slowly, monitoring horizons should be measured in months.

Chemical ecology

Aggregation pheromones in feces; sex pheromone (periplanone) biology studied as a model in chemical ecology.

Genetics and DNA

Genome sequenced 2018 (~3.38 Gb); expanded gene families linked to chemoreception, immunity and detoxification (Li et al., Nature Communications).

Taxonomy

Order Blattodea, family Blattidae. Described by Linnaeus, 1758. Largest of the common peridomestic cockroaches.

Open questions

Population connectivity between municipal sewer systems and building infestations; extent of metabolic resistance in Canadian populations.

References

Li et al. 2018, Nature Communications (genome)
Ebeling, W. Urban Entomology, UC Riverside
Mallis Handbook of Pest Control