Wildlife Review 2023: Arachnids (Spiders, Harvestman, Pseudoscorpions and Mites)

Spiders (Araneae)

Many species require microscopic examination to confirm identification, and with no specialist visits this year only 41 species were recorded, but two were added to the Warren audit, taking the total to 193 species. 

Winter active species at the start of the year were all associated with buildings and structures on site, these included the Cellar or Daddy-long-legs spider Pholcus phalangioides, the false widow spiders  Steatoda nobilis and S. bipunctatus, Missing Sector Orbweaver Zygiella x-notata and one of the zebra jumper spiders Salticus scenicus. Less expected was an unseasonal Nursery-web Spider Pisaura mirabilis on the early date of 31st January.

Nursery-web Spider Pisaura mirabilis - Dean Hall

Spring saw an increase in species with Cucumber Green Orb Spider Araniella cucurbitina on 2nd April, White-palped Jumper Euophrys frontalis on 7th, and the coastal wolf spider Pretty Perita Arctosa perita from 15th. Flower Crab Spider Misumena vatia were lying in wait for prey from 20th and another orb spider Zilla diodia was recorded on 28th. 

Pretty Perita Arctosa perita - Alan Keatley

In May, the tiny meshweb spider, Dictyna uncinata was found on 7th, together with two orb weavers, Larinioides cornutus and a new species, Bridge Spider Larinioides sclopetarius on 10th. Running crab spiders are numerous on site, but field identification is difficult, although the small male Philodromus dispar can be identified by size and colour; the first of the year was on 13th May. The distinctive and nationally scarce Bleeding-heart Spider Nigma puella was a good find on 16th with the equally scarce Royal Theridion Kochiura aulica on 19th. The more widespread Gorse Orbweaver Agalenatea redii was recorded from 20th May.

Flower Crab Spider Misumena vatia - Alan Keatley

June began with Sputnik Spider Paidiscura pallens, named after the shape of its eggcase, another running crab spider Tibellus oblongus on 3rd with the green-fanged Segestria florentina emerging from webs hidden in brickwork on 11th and the first Buzzing Spider Anyphaena accentuata the same day. In July the first extensive webs of the Labyrinth Spider Agelena labyrinthica were recorded on 9th with the crab spider Xysticus cristatus on 27th.

Paidiscura pallens eggcase - Kevin Rylands

Previously only known from Warren Point, several Dune Jumper Marpissa nivoyi were found on the Dune Ridge on 16th July. Most extraordinary a male of this dune dwelling species was also found near the Main Pond, later in the year indicating this nationally scarce species is more widespread on site than previously thought.

Dune Jumper Marpissa nivoyi - Alan Keatley

After a few sparse years the distinctive Wasp Spider Argiope bruennichi made a welcome recovery with several found in the meadows from 12th August. In past years this species has suffered from the over-wintering egg-sacs being unintentionally destroyed by mowing. The careful monitoring and avoidance of egg-sacs this year should aid their recovery.

Wasp Spider eggcase - Kevin Rylands

The second new orbweaver for the Recording Area this year, Four-spotted Orbweaver Araneus quadratus was found on 15th September. After its first appearance last year, an Invisible Spider Drapetisca socialis was located on 23rd November. Usually difficult to be seen on tree trucks, this one was more obvious on the viewing platform. The final spider species of the year was an Amaurobius similis on 11th December.

Invisible Spider Drapetisca socialis - Alan Keatley

Harvestmen (Opiliones)

Disappointingly only five harvestman species were found this year; Leiobunum rotundum on 22nd February, Paroligolophus agrestis from 11th June, Phalangium opilio on 27th July, Mitopus morio on 8th September and Leiobunum blackwalli on 16th October.

Leiobunum blackwalli - Alan Keatley

Pseudoscorpions (Chelonethida)

Rarely seen on site, the second record of the pseudoscorpion Moss Neobisiid Neobisium carcinoides was found on 11th February under a stone.

Moss Neobisiid Neobisium carcinoides - Alan Keatley

Mites (Acari)

Acari are small microscopic mites, some of which cause visible galls on their host plants, making recording somewhat easier! Galls of 17 species were noted during the year including Aceria ilicis on Holm Oak leaves, Eriophyes similis on Blackthorn leaves, Stenotarsonemus phragmitidis on Common Reed and, on Sea-purslane, Aceria brevipes (leaves) and Aceria obiones (flowers).

Aceria brevipes galls - Kevin Rylands