turf running spider

(Philodromus cespitum)

Conservation Status
turf running spider
Photo by Alfredo Colon
  IUCN Red List

not listed

     
  NatureServe

NNR - Unranked

     
  Minnesota

not listed

     
           
           
           
 
Description
 
 

Turf running spider is a small crab spider. It occurs in North America and Europe. It is the most common spider in European orchards. In the United States it is occurs from Maine to Washington south to Illinois and New Mexico. It is found in deciduous and coniferous woodlands on the bark and leaves of trees, on shrubs, in grasses, and on the ground in leaf litter.

The adult female is 316 to ¼ (4.5 to 6.1 mm) in length and has a to ¾ (15 to 20 mm) legspan. The male is a little smaller, to 316 (4.0 to 4.75 mm) in length. The body is soft, flattened, and smooth, with no rounded bumps (tubercles). It is weakly spined and is covered with soft, leaning (recumbent) hairs. The color can vary from mostly brown with pale mottling and dark brown markings, to mostly pale with brown markings.

The covering (carapace) of the front part of the body (cephalothorax) is as wide as long and is smoothly rounded on the sides, somewhat flattened when viewed from the side and somewhat circular when viewed from above. It is reddish brown on the sides with a broad pale band in the middle. There is a short, narrow, dark, longitudinal stripe on the rear margin, and a narrow, irregular, pale stripe on the lateral margins. On the female, a light V-shaped mark, lighter than the pale band, begins at about the middle of the carapace and extends forward to the anterior median eyes (AMEs). There are eight eyes arranged in two rows of four. None of the eyes are on tubercles and all of them are small. The four eyes in the back row are all the same size. The posterior median eyes (PMEs) are closer to the posterior lateral eyes (PLEs) than they are to each other. The median ocular area (MOA), the area defined by the middle four eyes, is wider than long.

The abdomen is flat, longer than wide, widest just beyond the middle, and broadly pointed at the tip. It is usually pale above and dark on the sides. There is a dark brown, elongated, oval-shaped mark (cardiac mark) on the front half, and dark chevrons on the rear half. The chevrons are sometimes interrupted, either once in the middle or once on each half. The underside of the abdomen is pale. Males are often darker, sometimes unifromly dark brown.

The legs are long and slender. They are longer and thinner on the male than on the female. They first, third, and fourth pairs of legs are nearly the same length and thickness, the second pair is only slightly longer. The front two pairs project outward rather than forward (laterigrade), allowing the spider to move quickly sideways, like a crab. This is the feature that gives the superfamily its common name. The legs are yellowish and slightly darker at the end of each segment. They are often speckled with brown on the side that faces forward (prolateral surface). The third segment (femur) on the front legs has three erect black spines on the upper surface. On each leg the last leg segment (tarsus) has a two claws, a well-developed, dense, brush-like tuft of microscopic hairs below (scopula), and a dense, brush-like tuft of microscopic hairs at the end (claw tuft). The claws, scopulae, and claw tufts are not visible to the naked eye.

 
     
 

Size

 
 

Female Body Length: 316 to ¼ (4.5 to 6.1 mm)

Male Body Length: to 316 (4.0 to 4.75 mm)

Legspan: to ¾ (15 to 20 mm)

 
     
 

Web

 
 

Running crab spiders do not build snares, retreats, or nests.

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Woodlands

 
     
 
Biology
 
 

Season

 
 

June to September

 
     
 

Behavior

 
 

The adult is able to move very fast. Its movements are rapid and erratic. While it may wait in ambush, it often hunts by running after prey. This is the feature that gives the family its common name.

 
     
 

Life Cycle

 
 

 

 
     
 

Food

 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 29, 30, 82.

Dondale, C. D. (1961). Revision of the aureolus group of the genus Philodromus (Araneae: Thomisidae) in North America. The Canadian Entomologist 93: 199-222.

 
  1/7/2022      
         
 

Occurrence

 
 

 

 
         
 
Taxonomy
 
  Class Arachnida (arachnids)  
 

Order

Araneae (spiders)  
 

Suborder

Araneomorphae (typical spiders)  
  Infraorder Entelegynae (entelegyne spiders)  
 

Superfamily

Thomisoidea (crab and running crab spiders)  
 

Family

Philodromidae (running crab spiders)  
 

Genus

Philodromus  
       
 

Synonyms

 
 

Aranea cespitum

Philodromus albicans

Philodromus cespiticolens

Philodromus cespiticolis

Philodromus maculatus

Philodromus obscurus

Philodromus reussi

Thomisus cespiticolens

 
       
 

Common Names

 
 

agile running crab spider

turf running spider

 

 

 

 

 

 

 

Glossary

Carapace

The hard, upper (dorsal), shell-like covering (exoskeleton) of the body or at least the thorax of many arthropods and of turtles and tortoises. On crustaceans, it covers the cephalothorax. On spiders, the top of the cephalothorax made from a series of fused sclerites.

 

Cardiac mark

An oval dark mark on the front half of the abdomen of some spiders, beneath which lies the heart.

 

Cephalothorax

The front part of the body of various arthropods, composed of the head region and the thoracic area fused together. Eyes, legs, and antennae are attached to this part.

 

Femur

On insects and arachnids, the third, largest, most robust segment of the leg, coming immediately before the tibia. On humans, the thigh bone.

 

Tarsus

On insects, the last two to five subdivisions of the leg, attached to the tibia; the foot. On spiders, the last segment of the leg. Plural: tarsi.

 

Tubercle

On plants and animals: a small, rounded, raised projection on the surface. On insects and spiders: a low, small, usually rounded, knob-like projection. On slugs: raised areas of skin between grooves covering the body.

 

 

 

 

 
 
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Alfredo Colon

 
    turf running spider   turf running spider  
           
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Other Videos
 
  Turf Running Spider (Philodromus cespitum) & a Spider-Hunting Wasp - Brighton, July 2021
Phil Booker
 
   
 
About

Jul 12, 2021

Running crab spiders belong to the family Philodromidae which includes over 600 species.

Markings can be variable, so I would have to qualify the species ID on this spider as 'probable' or 'most likely', as it's not possible to be 100% certain.

Running spiders are all non-web spinning, although they use silk for draglines and egg sacs.

Instead of trapping prey in a web, these spiders rely on their speed by simply waiting on vegetation until they detect a potential victim, before pouncing and injecting it with venom.

The venom paralyses its prey leaving the spider to consume it at its leisure.

But in this video, all was clearly not going to plan when I spotted an unidentified Spider-hunting wasp (of which there are approx. 40 species in the UK) turn the tables on this Turf-running spider.

The wasp had located the spider's egg sac hidden in the rolled up leaf and was using her ovipositor to inject her egg/s inside it through the leaf.

The mother knows something is amiss, but is clearly wary of the wasp. It appears unsure what to do, and its attempts to chase the wasp away appear nervous and half-hearted.

The wasp in turn doesn't appear to be too bothered about the spider and appears if anything, to be taunting it rather than contemplating a direct attack?

Either way the wasp has succeeded in fatally compromising the spider's egg sac.

After the attack, I watched the mother run round and round the rolled up leaf many times in what looked like panic, before she suddenly disappeared into the undergrowth?

Has she abandoned the sac?

I don't know?

If you have an idea, please feel free to let me know in the comments section.

PK

(Please subscribe to this channel for over 300m of my short wildlife videos, from the UK and overseas - thank you)

 

 

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  Alfredo Colon
5/30/2021

Location: Woodbury, MN

turf running spider  
  Alfredo Colon
8/13/2019

Location: Woodbury, MN

turf running spider  
  Alfredo Colon
8/4/2019

Location: Woodbury, MN

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Created: 1/7/2022

Last Updated:

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