Spider Citizen Science App
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LET'S SPOT SPIDERS!

Download the SpiderSpotter App for Android or IOS and help with your observations!

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MEASURE SPIDER WEBS

Do spiders in cities build their webs differently from spiders in natural habitats? Use the SpiderSpotter Card to help research!
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SO MANY SPECIES!

Spiders are a diverse order! Browse our collection of spider species, which you also can find in the SpiderSpotter App.

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Bram Vanthournout

Bram Vanthournout

Friday, 06 September 2019 09:39

Goldenrod spider

Goldenrod spider (Misumena vatia)

Web: Crab spiders don’t make catching webs, but use their elongated first and second legs to overpower their prey. They are sit and wait predators, often well camouflaged and laying in an ambush to surprise passing prey.

Habitat: in sunny environments such as grassland, forest edges, but also gardens. Is very often found on flowers.

How to recognize?

  • ♀: colour variable: white to yellow to greenish, sometimes with red stripes
  • ♂: cephalothorax brown to black
  • ♂: abdomen white with two dark length stripes.

Looks similar to:

  • This species is hard to confuse with any other species when observed in detail.

Size

♀: 9-11 mm

♂: 3-4 mm

When?

♀: May till August

♂: May till August

Friday, 06 September 2019 09:38

Common crab spider

Common crab spider (Xysticus cristatus)

Web: Crab spiders don’t make catching webs, but use their elongated first and second legs to overpower their prey. They are sit and wait predators, often well camouflaged and laying in an ambush to surprise passing prey.

Habitat: in many different environments such as grassland, on bushes and other low vegetation, rather in open habitats.

How to recognize:

  • light to dark brown colour
  • cephalothorax with clear dark triangle
  • abdomen with a lighter pattern (in the shape of a pine tree)

Looks similar to:

  • several other Xysticus species. Only close study with a stereomicroscope will allow for a certain identification.

Size

♀: 9-11 mm

♂: 3-4 mm

When?

♀: April till August

♂: April till August

Friday, 06 September 2019 09:37

Ozyptila praticola

Ozyptila praticola

Web: Crab spiders don’t make catching webs, but use their elongated first and second legs to overpower their prey. They are sit and wait predators, often well camouflaged and laying in an ambush to surprise passing prey.

Habitat: on the ground, in leaf litter or sometimes on low vegetation in gardens, parcs, forest,…

How to recognize:

  • dark brown colour
  • cephalothorax with clear black drawing with lighter mid band
  • abdomen with vague drawing, often with two clearly noticeable dark stripes, going from the middle to the sides.
  • legs dark annulated

Looks similar to:

  • several other Ozyptila species, only detailed study of the reproductive structures with a stereomicroscope will allow for a certain identification.

Size

♀: 3-5 mm

♂: 2,5-3 mm

When?

♀: April till September

♂: April till September

Friday, 06 September 2019 09:37

Eurasian green crab spider

Eurasian green crab spider (Diaea dorsata)
German name: Grüne Krabbenspinne

Web: Crab spiders don’t make catching webs, but use their elongated first and second legs to overpower their prey. They are sit and wait predators, often well camouflaged and laying in an ambush to surprise passing prey.

Habitat: on leaves of bushes and trees.

How to recognize:

  • lightly coloured abdomen with clearly delineated dark figure in the shape of a leaf. Lighter spots in leaf figure (sometimes absent)
  • ♀: cephalothorax and legs light green
  • ♂: cephalothorax yellow to green, first two leg pairs with dark bands.

Looks similar to:

  • Triangle crab spider, but the dark drawing on the back of the abdomen has a different shape (often an incomplete triangle).

Size

♀: 5-7 mm

♂: 3-4 mm

When?

♀: May till June

♂: May till June

Friday, 06 September 2019 09:30

Rabbit hutch spider

Rabbit hutch spider (Steatoda bipunctata)

Web: 3D web with messy threads and often vertical threads with glue on the lower part towards the substrate (“gum footed threads”). The web sometimes has a matlike appearance.

Habitat: Mostly close to or in buildings, but also regularly outdoor in hollow trees, away from buildings. The spider often hides in a crevice.

Herkennen aan:

  • glossy, coffeebean like appearance, especially when the spider feigns death after being disturbed and retracts its legs
  • often with light stripe over the middle of the abdomen
  • male with strikingly large pedipalps

Looks similar to:

  • upon close inspection not really to be confused with any other species.

Size

♀: 4,5-7mm

♂: 4-5,5mm

When?

♀: throughout the year

♂: April till November

Friday, 06 September 2019 09:29

Triangulate combfoot

Triangulate combfoot (Steatoda triangulosa)

Web: 3D web with messy threads and often vertical threads with glue on the lower part towards the substrate (“gum footed threads”). The web sometimes has a matlike appearance.  

Habitat: Mainly in dark places in buildings, contrary to the False black widow also in dry places such as attics. Or in living rooms on the underside of furniture, where you can often find egg sacs.  Regularly also outdoors near solid structures. The spider usually hides in crevices.

How to recognize:

  • lighter triangles almost always present on the backside of the abdomen.
  • legs often ligther coloured and more or less clearly annulated.

Looks similar to:

  • the False black widow spider, but the lighter triangles on the abdomen of the Triangulate combfoot (Steatoda triangulosa) are touching.

Size

♀: 3,5-7mm

♂: 3,5-5mm

When?

♀: throughout the year

♂: June till October

Friday, 06 September 2019 09:29

False black widow

False black widow (Steatoda grossa)

Web: 3D web with messy threads and often vertical threads with glue on the lower part towards the substrate (“gum footed threads”).

Habitat: Mainly in dark places in buildings (preference for cellars, where webs are constructed close to the cellar window), but also outdoors near solid structures. The spider usually hides in crevices.

Hot to recognize:

  • often (but not always) with lighter triangles on the backside of the abdomen
  • larger than the other Steatoda species
  • male is considerably smaller than female.

Looks similar to:

  • is often mistakenly regarded as a Black widow, but lacks the red hourglass-shaped figure on the underside of the abdomen and is usually also much smaller
  • is distinguishable from the Triangulate combfoot by having non touching lighter triangles on the abdomen.

Size

♀: 6,5-10mm

♂: 4-6mm

When?

♀: throughout the year

♂: August till September

Friday, 06 September 2019 09:23

Common stretch spider

Common stretch spider (Tetragnatha extensa)

Web: orb web with open centre (no threads).

Habitat: tall grasses (such as reeds) and low vegetation close to water. op hoge grassen (bijv. riet) en lage vegetatie in de buurt van water. More strongly bound to water than the Silver stretch spider.

How to recognize:

  • elongated body with long legs
  • ♂: extended jaws (chelicerae)
  • cephalothorax and legs brown
  • abdomen yellow to green, with a silver shine and a dark branched figure. Underside with a broad, black stripe.

Looks similar to :

  • Silver stretch spider. The underside of the cephalothorax (sternum) of the Common stretch spider has a clear, light spot in the middle. The sternum of the Silver stretch spider has a uniform colour.

Size

♀: 10-12 mm

♂: 6-9 mm

When?

♀: May till July

♂: May till July

Friday, 06 September 2019 09:22

Silver stretch spider

Silver stretch spider (Tetragnatha montana)

Web: orb web with open centre (no threads).

Habitat: occurs frequently on shaded banks, but also in bushes of gardens and parcs. Less bound to water compared to the Common stretch spider.

How to recognize:

  • • elongated body with long legs
  • • ♂: extended jaws (chelicerae)
  • • cephalothorax and legs brown (legs often with dark spots)
  • • abdomen yellowish, with a dark grey to greenish branched figure with a golden appearance.

Looks similar to:

  • • the Common stretch spider (Tetragnatha extensa). The underside of the cephalothorax (sternum) of a Silver stretch spider has a uniform colour. The Common stretch spider has a clear, light spot in the middle.

Size

♀: 7-13 mm

♂: 6-8 mm

When?

♀: May till July

♂: May till July

Friday, 06 September 2019 09:22

Lesser garden spider

Lesser garden spider (Metellina segmentata)

Web: small orb web that is suspended under an angle in grasses, herbs and low bushes.

Habitat: on vegetation in a lot of different habitats such as roadside, grassland, gardens, woodland. Often in large numbers.

How to recognize:

  • cephalothorax with dark, Y-shaped figure
  • abdomen white to yellow to reddish, with vague leaf figure.

Looks similar to:

  • Can only be reliably distinguished from Metellina mengei based on the reproductive organs.

Size

♀: 6,5-9 mm

♂: 7-7,5 mm

When?

♀: August till October, but in mild winters, sometimes till early spring

♂: August till October

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Spot spiders in the SPOTTERON Citizen Science app

Step 1: Citizen Science App Download

Download

Get the free Citizen Science App on Google Play for Android or in the Apple App Store.
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After the start of the app you can register your own user account with just your eMail adress.
Step 1: Citizen Science App Download

Start observing

Start observing! You are automatically logged-in after registering to add your first observation.
 

 

Download the App on your smartphone now or open the map in your browser:

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Download the SpiderSpotter Card!

Do you want to help measuring spiders for science? Download the SpiderSpotter Card for self printing at home and hold it in the pictures you take in the SpiderSpotter App. With the measurement reference, we can determine the size of your spider or web observation better. You can also order it at spiderspotter@UGent.be, provide your address and the number of cards you need and we will send them to you!

When holding the SpiderSpotter Card near the spider or a spider's web, please make sure that a ruler and one of the brigthness gradient strips is visible in the picture. You can read more about how to take the pics in our info section!

Download the Spider Spotter StripDownload PDF

Download the Spider Spotter Card

Help to measure the Spiders!

With the new SpiderSpotter Data Analysis Tool, you can actively participate in generating scientific data! The online interface fetches spider observations live from the Citizen Science App and offers a range of tools to measure the size and the average colour of the spiders. Simply access the Data Analysis Tool and log in with your App account!

You can even select an option to just work with your observations from the App and export your measured data if you want to do your own analysis.

Download the Spider Spotter StripAccess Data Analysis Tool

New Spots from the Citizen Science App

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Datum: 15.05.2025 09:41:47

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Datum: 10.05.2025 13:20:15