Distributions of Large House spiders in the north-east a Victorian - - PowerPoint PPT Presentation

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Distributions of Large House spiders in the north-east a Victorian - - PowerPoint PPT Presentation

Oct 14, 2022 287 likes •501 views

Distributions of Large House spiders in the north-east a Victorian legacy? Geoff Oxford Species of Tegenaria in the British Isles associated with human habitation * * * Oxford (2011) British Wildlife 23 : 34-41. The fishing

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Distributions of Large House spiders in the north-east – a Victorian legacy?

Geoff Oxford

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Species of Tegenaria in the British Isles associated with human habitation

Oxford (2011) British Wildlife 23: 34-41.

* * *

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The ‘fishing’ technique

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  • T. gigantea/saeva

Bristowe 1939

Pre-1974 county boundaries

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  • T. gigantea/saeva

Bristowe 1939 Locket, Millidge & Merrett 1974

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  • T. gigantea/saeva

Bristowe 1939 Locket, Millidge & Merrett 1974 Merrett 1980

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  • T. gigantea/saeva

Bristowe 1939 Locket, Millidge & Merrett 1974 Merrett 1980 Harvey, Nellist & Telfer 2002

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Bristowe 1939 Locket, Millidge & Merrett 1974 Merrett 1980 Harvey, Nellist & Telfer 2002 SRS maps 2006

  • T. gigantea/saeva
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  • T. domestica

Bristowe 1939

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Distributions of Tegenaria saeva, T. gigantea and their hybrids in Britain

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Distributions of T. saeva and T. gigantea around 1900

  • T. saeva
  • T. gigantea

Area of overlap

Oxford (2009) Bull. Br. arachnol. Soc. 14: 297-302

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Tegenaria atrica in the British Isles

http://www.flickr.com/photos/nuclearlakeside Oxford, G. S. & Chesney, H. C. G. (1994)

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= Tegenaria gigantea = T. saeva = T. atrica = T. saeva/T. gigantea hybrids

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= Tegenaria gigantea = T. saeva = T. atrica = T. saeva/T. gigantea hybrids

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= T. atrica

Original Burnopfield location

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= T. atrica

= T. atrica + others

= T. gigantea and/or saeva

Jesmond 1887 (Hull, 1896) Axwell Park 1910 (Bagnell & Turner, 1913) Winlaton 18?? (Hull, 1896)

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‘The 14 years or more between Hull’s Winlaton specimen and those from Axwell Park suggest that a viable population may have been established in this area around the turn of the twentieth century.’ (Oxford, 2009, p.298)

A prophetic statement …?

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Implications

  • 1. Some T. atrica records from northern Britain might have resulted

from local movement rather than foreign imports e.g. Low Newton, near Craster (1996).

  • 2. There may be competitive exclusion within the Tegenaria atrica

group such that once one species is well-established, it is difficult for others to invade.

  • 3. This might also be a factor preventing fusion at the boundary

between T. saeva and T. gigantea in the south.

  • 4. However, it is difficult to imagine exactly how this competitive

exclusion might work.

  • 5. Without the original specimens from the Newcastle area, it is

impossible to prove the idea of a Victorian legacy, but it’s the best bet so far!

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… any questions?