Eratigena duellica – The Giant House Spider

The genus to which the Giant House Spider is assigned is relatively new. Until recently Eratigena duellica was called Tegenaria gigantea (therefore belonging to the genus Tegenaria). However a handful of species were removed from Tegenaria to the newly created genus Eratigena and our friend below we think was one of them…

According to Britains Spiders: A field Guide (ref 7), the main difference between the two genus (Eratigena & Tegenaria) seems to be the lack of ‘annulations’ on the legs of Eratigena species.

NOTE: Annulations refers to rings upon the legs of the spider, which as can be seen above our specimen lacks. By way of a comparison the annulations can clearly be seen on the familiar Garden Spider Araniella diadematus.

Our ID of this species is not 100% confirmed as most other Eratigena look similar and a detailed examination, possibly with a microscope would be required. This lack of confidence is supported by this species not being common in the West of England, where the species Eratigena Savea seems to almost replace it. To further confuse matters, some authorities believe Eratigena duellica and Eratigena Savea are in fact the same species and there are reports that the two species where they overlap in range can hybridise and produce fertile offspring (1).

The same source (1) also explains some of the life cycle of this species. Both males and females over winter as half grown juveniles and mate the following year, after which the males perish. The females can go on to live for another whole year.

The species is known as ‘syanthropic’, which simply means it is a species that tends to live around people, but can and does survive happily in many other habitats.

  1. Spider and Harvestman Recording Scheme website: Summary for Eratigena duellica (Araneae). Accessed online October 11th 2022.