Monday 28 December 2020

Wildlife Review 2020: Spiders and Harvestmen

Spiders

A total of 46 species were recorded this year including no fewer than 14 new species for the Warren. 

A survey failed to find Euophrys herbigrada, a small jumping spider that occurs at only six other UK sites and was last recorded here in 1995. However it did reveal 10 new species to the Warren and nine not recorded for over 25 years. One of the new records was Royal Theridion Kochiura aulica, a Nationally Scarce B species associated with Gorse.

Other news species recorded during the year included the Green Crab Spider Didea dorsata and the impressive Green-fanged Tube Spider Segestria florentina.

Nursery-web Spider - Alan Keatley

Commoner spiders included an early Nursery-web Spider Pisaura mirabilis on 1 February and the first Zebra Jumping Spider Salticus scenicus on 2 March. Other spiders in evidence from mid-May included the wolf spiders Pardosa  monticola, nigripes and pullata, the Bleeding Heart Spider Nigma puella and the crab spider Xysticus kochi. 

Zebra Jumping Spider - Alan Keatley

Later in the year Copper Sunjumper Heliophanus cupreus and large numbers of the Garden Orbweaver Araneus diadematus were found.

Unfortunately after a 20 year presence there were no reports of Wasp Spider Argiope bruennichi this year, a spider that had become a late summer feature on site. The loss of areas of longer vegetation overwinter has impacted heavily on this species and many other invertebrates. 

Another potentially lost spider is the Dune Jumper Marpissa nivoyi, a nationally scarce A species at its only south Devon site, the rapidly increased erosion has removed the majority of its known habitat. Both species are priorities for monitoring next year. 

Harvestmen

Six species were recorded including Dicranopalpus ramosusLeiobunum rotundum, Phalangium opilio and the introduced species Opilio canestrinii, only the fifth Devon record.

Leiobunum rotundum - Alan Keatley

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