Why house centipedes in BC are your best ally against silverfish and cockroach nymphs

What house centipedes eat — and why it matters in BC

Scutigera coleoptrata is a generalist predator that ambushes prey in dark, enclosed spaces. Its prey list in BC homes: silverfish (primary prey in damp basements), German cockroach nymphs and adults, various ant species, small flies including fungus gnats and drain flies, spiders, and any other soft-bodied arthropod in its size range. For BC homeowners dealing with silverfish — the most common occasional invader driven by our wet climate — house centipedes provide continuous biological suppression. A single centipede eating 3–4 silverfish per night over a year consumes more silverfish than a single pesticide application. The biological control is persistent; chemical control degrades over weeks. The limitation: house centipedes don't eliminate prey populations, they suppress them. And their presence is a reliable signal of how large the prey population is. More centipedes means more prey. If you're seeing 5+ centipedes per week, you have a larger underlying silverfish or other arthropod population than you probably want.

1–2 house centipedes seen per month: baseline predator presence in any BC basement — normal, no intervention needed.
3–5 per week: elevated prey — investigate moisture conditions driving silverfish or similar prey.
Daily sightings across multiple rooms: significant prey infestation — comprehensive moisture or other inspection warranted.
Centipedes in upper floors (kitchen, bedroom): unusual — indicates heavy population pressure from below or overlooked harborage zone.

The predator-prey feedback: why centipede treatment alone doesn't work

When we apply pyrethroid treatments targeting house centipedes without addressing their prey, results are predictably short-lived. The prey population — particularly silverfish — continues uncontrolled. Within weeks, surviving centipedes or new individuals moving in from adjacent areas find abundant food and the population rebounds. The durable approach is always: (1) address the moisture conditions driving silverfish and other moisture-dependent prey; (2) wait 30–60 days for the prey population to decline; (3) observe whether centipede counts drop correspondingly. They do. The centipede population is directly indexed to prey availability. Remove the prey and you remove the centipedes without targeting them directly.

Frequently asked questions

Do house centipedes actually make a measurable difference to silverfish populations?+

Yes — in enclosed basement environments with limited immigration from outside, centipede predation demonstrably suppresses silverfish counts. The effect is stronger in spaces where silverfish can't continuously recolonise from adjacent wall voids. Centipedes can't eliminate an established population, but they maintain suppression pressure 24/7 in a way that periodic chemical treatments don't.

What should I do if I have many house centipedes?+

Treat the prey, not the centipedes. Identify and address the moisture source supporting silverfish or other prey species. Apply targeted moisture management — dehumidifier, vapour barrier, ventilation improvement. Re-inspect after 45 days. Centipede counts should drop as the prey population declines.

My kids are scared of house centipedes. Is there a middle-ground approach?+

Reduce centipede numbers by reducing prey (moisture management) while accepting that some will persist. To prevent upper-floor encounters, seal the crawlspace-to-basement transition and basement-to-first-floor utility penetrations. Dehumidification and prey reduction typically produces a 60–80% reduction in visible centipede activity within 60 days.