Eratigena agrestis (Walckenaer, 1802)

Hobo spider

A Pacific Northwest spider wrongly famous for dangerous bites, not found in Ontario.

Order: Araneae
Family: Agelenidae
Group: Spiders
Ontario status: Not established in Ontario, Pacific Northwest reference species

Why it matters

It matters as a lesson in how spider myths are made: the hobo spider was declared dangerously venomous in the 1980s on thin evidence, and decades of follow-up research found nothing. It is included here so Ontario readers can stop worrying about it.

Origin

Europe; introduced to the Pacific Northwest of North America, where it is common in and around houses.

Behavior

Fast-running funnel-weaver. Males wander in late summer searching for females, which is when most indoor sightings happen, again, in the Pacific Northwest.

Living conditions

Builds funnel-shaped webs in basements, window wells, and foundation cracks, in the Pacific Northwest, not Ontario.

Signs of presence

In Ontario: essentially none, a 'hobo spider' here is almost certainly a giant house spider or grass spider
In the Pacific Northwest: flat funnel webs at floor-wall junctions, fast brown spiders

Weaknesses

Does not occur in Ontario, which resolves most concerns immediately
Where it does occur, it is managed by sealing foundation gaps and removing ground-level clutter
Funnel webs are conspicuous and easy to vacuum
Males wander only briefly in late summer

Myths and facts

Myth Hobo spiders cause necrotic flesh wounds and are spreading across Canada.
Reality Controlled studies and poison-center data found no evidence of medically significant bites. It is not established in Ontario and is not spreading here.

Research notes

Morphology

Body 7-15 mm; brown with chevron pattern on abdomen; long legs; prominent posterior spinnerets (agelenid 'twin tails'). Males have enlarged pedipalps in late summer.

Diagnostics

Reliable species separation from E. atrica/duellica requires genitalia examination by an arachnologist, field ID to species is unreliable, which is part of why bite attributions were worthless.

Easily confused with

Giant house spiders (Eratigena atrica and E. duellica, separate species) Larger on average and genuinely present in Ontario; separable only by genitalia, treat any Ontario 'hobo' as this instead.
Grass spiders (Agelenopsis spp.) Build outdoor funnel webs in grass; longer spinnerets; not indoor species.

Life cycle

Adult: Annual; males mature and wander in late summer
Egg: 50-100+ eggs per sac in the retreat
Egg to adult: One season
Generations per year: One
Nymph or larva: Spiderlings remain in the maternal web briefly

Development

Egg to spiderling to adult through successive molts; egg sacs guarded in the funnel retreat.

Reproduction

Males abandon webs in late summer to find females; mating in the female's funnel.

Distribution

Global: Europe; introduced Pacific Northwest North America
Native range: Europe and western Asia
Ontario: Not established; no confirmed breeding populations. Any Ontario report should be treated as a misidentification pending voucher specimen.

Ecology

Ground-level funnel-web predator. In its introduced PNW range it occupies the same niche as native agelenids. Absent from Ontario's fauna.

Resistance

Unknown, no documented resistance.

IPM implications

None in Ontario. Included in this library as a reference and myth-buster: when a client reports a 'hobo spider,' the professional response is identification first, it will be something else, and education about how the myth was debunked.

Chemical ecology

Venom studied specifically because of the necrosis claims: assays show no unusual cytotoxicity, and the medical literature contains no verified necrotic bite. A textbook case of venom myth outrunning data.

Genetics and DNA

No reference genome published as of 2026.

Taxonomy

Order Araneae, family Agelenidae. Authority (Walckenaer, 1802). Formerly Tegenaria agrestis; moved to Eratigena on molecular evidence. Very close to E. atrica/duellica (giant house spider).

Open questions

Precise PNW range dynamics; the original misattribution chain is itself a case study in science communication failure.

References

Foelix, R.F. (2011). Biology of Spiders, 3rd ed., Oxford University Press.
Vetter, R.S., UC Riverside spider-bite myth research (various publications).