What the data shows
For temperate species like Tegenaria/Eratigena (giant house spider) and Steatoda, males reach maturity in late summer and wander widely in search of receptive females. Most large indoor spiders seen in September and October are male.
Females tend to remain in established webs. Encountering a male is a transient event; the population indoors is not actually rising.
References
- [1]Seasonality of indoor encounters with synanthropic spiders - Royal Society Open Science. Accessed June 2026.
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