Why is finding one cockroach a sign that there are many more hidden?
Why is finding one cockroach a sign that there are many more hidden?
Cockroaches are social insects; their feces contain aggregation pheromones that attract others to join them. They are also reclusive and nearly inactive during the day. So when you see one out and about, it often means their hiding place is overcrowded or food is scarce, forcing them to venture out during the day.
Cockroach species and sizes
Two main species are common in homes: the German cockroach (1-1.5 cm, light brown) and the American cockroach (3-4 cm, reddish-brown). The German cockroach reproduces faster and is harder to eradicate; the American cockroach is larger and often enters through drains.
Why does finding one mean there's a nest?
- A single female cockroach's ootheca (egg case) can hatch 20-40 nymphs; the ootheca incubates for about 28 days, meaning very rapid reproduction.
- Cockroach feces and secretions attract more of their kind to congregate.
- They hide in crevices during the day and come out at night, making them hard to spot normally.
- Finding one active individual suggests there may already be dozens or hundreds in the nest.
Three things to do immediately upon finding a cockroach
- After turning off the lights that night, check kitchen cabinets, sink edges, and behind the refrigerator to locate the nest.
- Spray dinotefuran-containing household insecticide along their travel routes.
- Clean up food residues and water sources to reduce their food supply.