six-spotted fishing spider

(Dolomedes triton)

               
Conservation Status

IUCN Red List

not yet assessed

six-spotted fishing spider

NatureServe

NNR - Unranked

Minnesota

not listed

Occurrence

Widespread

Season

 

Habitat/Host

Ponds, lakes, swamps, slow-moving streams

Size

Female Body Length: to ¾

Male Body Length: to ½

Legspan: 2 to 3

          Photo by Kirk Nelson

Identification

This is a large, robust, nursery web spider. It is one of the largest spiders encountered in Minnesota. The adult female body is dark brown with light markings and to ¾ long with a legspan of 2 to 3.

The front part of the body (cephalothorax) is about the same size as the rear part (abdomen). The covering (carapace) of the cephalothorax is dark gray to brown or greenish-brown with a bold, silvery-white to yellow stripe along each side. There is often a narrow pale center (middorsal) line and two shorter lateral lines that form a poorly developed trident shape.

The abdomen is dark gray to brown, rounded in the front, widest in the middle, and tapers toward the rear. There is a broad white stripe running down each side and two rows of six small white spots on the upper (dorsal) surface. The spots are usually prominent, sometimes barely discernible. The underside (sternum) is paler. There are six black spots between the leg bases for which this species gets its common name.

The legs are long, thin and dark brown with thin, pale, longitudinal stripes. They are not horizontally banded. They are covered with hairs and have long black spines. The last leg segment (tarsus) has 3 claws, but these are not visible without magnification.

The male is similar to the female but only about half the size.

 
Similar
Species

Dark fishing spider (Dolomedes tenebrosus) is larger. It lacks the bold white stripes on the cephalothorax and abdomen. The legs appear horizontally banded, not longitudinally striped.


Food

Aquatic insects, small tadpoles, tiny fish, other insects that fall on the water surface

 
Life Cycle

Mating takes place between June and September. It may be the last act of the male, as the female is cannibalistic. After mating, the female produces a large egg sac, 5 16 to in diameter, into which she begins laying eggs. She carries the egg sac around with her mouth as she wanders about. While carrying it, she cannot feed. When the eggs are about the hatch she attaches the sac between leaves in a shelter (nursery) which she has created. She then guards the nursery until the hatchlings disperse in about a week.

Immature adults hibernate near water under stones, under loose bark, or other debris. Males mature and mate in the spring of the first year. Females mature in two years.

 
Behavior

This spider does not produce a web to catch prey. The female produces a nursery web for its young.

It is active during the day. It floats, and can run across the water surface like a water strider. When hunting, it perches on floating vegetation, detecting ripples and vibrations in the water with three of its front legs. It sometimes dives up to 7 for prey or to escape a predator. It can create a bubble of air that allows it to stay under water for a half hour or more.


Distribution Distribution Map   Sources: 24, 29, 30.

Comments

 


Taxonomy

Order:

Araneae (spiders)

 

Suborder:

Araneomorphae

 

No Rank:

Entelegynae (eight-eyed spiders)

 

No Rank:

RTA clade

 

Superfamily:

Lycosoidea

 

Family:

Pisauridae (nursery web spiders)

 
Synonyms

 

 
Common
Names

six-spotted fishing spider

sixspotted fishing 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.

 

Cephalothorax

The front part of a spider’s body, composed of the head region and the thoracic area fused together. Eyes, legs, and antennae are attached to this part.

 

Tarsus

The last two to five subdivisions of an insect’s leg, attached to the tibia; the foot. Plural: tarsi.

 

 

       

Visitor Photos

   
Share your photo of this arachnid.

Kirk Nelson


Lebanon Hills Regional Park

Near the fishing pier on McDonough Lake

  six-spotted fishing spider   six-spotted fishing spider

       
       

MinnesotaSeasons.com Photos

   
       
       
       

 

Camera

     

Slideshows

   
  Pisauridae (Nursery Web and Fishing Spiders)
Judy Gallagher
 
  Pisauridae (Nursery Web and Fishing Spiders)  

 

slideshow

     

Visitor Videos

   
Share your video of this arachnid.

     
     

Other Videos

 
  Scary Spider Under Water! - Six spotted fishing spider.
Nature Now! - Chris Egnoto
 
   
 
About

Published on May 17, 2017

This spider dives under water! This is a pretty crazy video where I film a six spotted fishing spider. She dives beneath the surface of the water where I film her more. You can see a silvery sheen all over her body from trapped air that allows her to breath underwater. Really neat.

 
     
  Six-spotted Fishing Spider (Pisauridae: Dolomedes triton) Lateral Close-up
Carl Barrentine
 
   
 
About

Published on Jun 19, 2012

Photographed at Grand Forks, North Dakota (18 June 2012).

 
     
  Six-spotted Fishing Spider Male and Female (Dolomedes triton)
Nature in Motion
 
   
 
About

Published on Aug 30, 2016

Includes web-building, interaction between male and female, plus other behaviors. This is the most aquatic Dolomedes, usually found on still water near the edges of ponds or lake margins. If disturbed, they may climb down emergent vegetation and hide underwater. Pisauridae Dolomedes triton

 
     
  Six-spotted Fishing Spider striking and diving in slow motion (Dolomedes triton)
Nature in Motion
 
   
 
About

Published on Mar 21, 2017

Two different fishing spiders striking at prey and diving underwater. Each clip is in real time and then repeated at 10% speed. Notice how much more action is visible in slow motion. Filmed at a farm pond in the Missouri Ozarks, USA, on March 19, 2017. Pisauridae - Dolomedes - triton

Music: Carny's Dance by Kevin MacLeod is licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/by/4.0/)

Source: https://soundcloud.com/kevin-9-1/carnys-dance

Artist: http://incompetech.com/

 
     

 

Camcorder

         

Visitor Sightings

   
Share your sighting of this arachnid.

Kirk Nelson
6/24/2018

Location: Lebanon Hills Regional Park

Near the fishing pier on McDonough Lake

six-spotted fishing spider


     
     
 

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