Dolomedes triton (Six-spotted Fishing Spider)

About Dolomedes triton

Taxonomic Hierarchy

→ Kingdom: Animalia
→ Phylum: Arthropoda
→ Class: Arachnida
→ Order: Araneae
→ Family: Pisauridae
→ Genus: Dolomedes
→ Species: Dolomedes triton

Common Name (Official / AAS)

Six-spotted Fishing Spider

Other Common Names

Fishing Spider, Nursery Web Spider, Raft Spider

Author

Author of species name: Charles Athanase Walckenaer. First year published: 1837, as Lycosa triton.

Pronunciation

doh-loh-MEE-deez TRY-tun

Meaning

Dolomedes apparently means “wily” or “contriving” in Greek (Cameron 2005); triton is after the Greek mythological sea god.

Notable Previous Names

Dolomedes sexpunctatus

Identifying Traits of Dolomedes triton

Size

Body length (excluding legs) of adult female ranges from 13-20 mm; adult males range from 8-11 mm.

Female Primary Colors

Male Primary Colors

Eye diagram of Dolomedes triton

Eyes

Total of eight eyes. When viewed from the front, two horizontal rows of four, each row slightly recurved. Posterior eyes larger than the anterior eyes. See eye diagram.

Legs

Mature individuals are very large, “sprawling” spiders. Legs typically match the dark brown color of the rest of the body, but may have scattered white hairs or dark marks. Upon close inspection, there are numerous thick, black spines (macrosetae) on legs. The tarsi (tips of legs) have 3 claws.

Body

Cephalothorax and abdomen of about equal size. Robust spiders. Abdomen rounded in the front, widest in the middle, and tapered towards the rear. Abdomen base color dark brown or tan with white sides and pairs of white spots down the center. Cephalothorax also dark brown and with a white (or yellow) stripe on the perimeter of each side, running its full length. The sternum (underside of cephalothorax) has six black spots, which is where the common name “sixspotted fishing spider” comes from. It’s a common misconception that the name is based on the white spots on the abdomen; there are usually way more than six, anyways.

Range of Dolomedes triton

Dolomedes triton can be found in the following states, provinces and territories across the United States and Canada. Our current understanding of each spider's distribution is drawn from numerous scientific publications and online spider submissions, in order to be as accurate as possible. It is important to remember that spiders do not adhere to the territorial lines decided on by humans, therefore these ranges are subject to change.

Important Range Notes

This species is widespread across all of North America, but is less common in the Pacific Northwest. It has also been collected in Cuba. A disclaimer: aside from some unverifiable specimens collected by Prof. Carl Lindroth and Dr. Ernst Palmen in 1949 and 1951 (identified by Walter Hackman as Dolomedes scapularis, a junior synonym of D. triton), there are not currently any published records of this species occurring in the Canadian province of Newfoundland & Labrador, but we would expect the species to be found there and have added it to our range listing.

United States

Canada

Additional Information

Habitat

This species is the most truly aquatic of all our fishing spiders in North America. Found on the margins of quiet lakes, ponds, rivers, and streams. Sometimes even found floating on the surface of swimming pools in urban situations.

Web

This is a powerful hunting spider that does not spin a prey-catching snare. Females will, however, construct a tangled “nursery web” among foliage where they will suspend their egg sac and guard the emerging spiderlings.

Season

It appears that adults of this species can be found at any time of year, though it is most common for them to mature in late spring and lay eggs in late summer. Immature specimens overwinter in debris and leaf litter on the margins of the water bodies.

Food

Typically aquatic insects and other water-borne prey that the spider can overpower. This includes small fish (e.g. minnows) and frogs, etc. This species will even dive below the surface of the water when escaping predators or trying to catch food.

Lifecycle

Egg sacs are produced about 10-14 days after mating. The egg sac is a brown sphere, approximately 8-10 mm in diameter, held in the jaws of the female as she wanders. Egg sac defense by the female is vigorous to the point that egg sacs cannot be removed from the female’s mouthparts without ripping the outer lining of the eggsac (Johnson & Sih 2007). Eventually the spider suspends her egg sac in a tangled “nursery web” amid foliage well off the ground, sometimes above the water. There she stands guard over the package and the spiderlings that later emerge from it. The spiderlings will remain in the nursery web until their next molt, at which time they disperse.

Remarks

Pictures of Dolomedes triton (Six-spotted Fishing Spider)

General

Female Spiders

Male Spiders

Filtering options are grayed out when we do not have pictures for the given perspective. If you are a spider photographer, you can submit pictures of spiders to help fill any voids in our ever expanding library.
  • Dolomedes triton
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Dorsal
  • State: Connecticut
  • Country: United States
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Dorsal, Spiderlings
  • State: Kentucky
  • Country: United States
  • Dolomedes triton
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Dorsal
  • State: Connecticut
  • Country: United States
  • Dolomedes triton
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Dorsal
  • State: Connecticut
  • Country: United States
  • Dolomedes triton
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Dorsal, Eyes
  • State: Connecticut
  • Country: United States
  • Dolomedes triton
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Dorsal
  • State: Connecticut
  • Country: United States
  • Dolomedes triton
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Egg Sacs, Lateral
  • City/Region: Fairfield
  • State: Pennsylvania
  • Country: United States
  • Dolomedes triton
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Egg Sacs, Eyes
  • State: Maryland
  • Country: United States
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Dorsal
  • City/Region: Harvard, Worcester County
  • State: Massachusetts
  • Country: United States
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Dorsal
  • City/Region: Raab Corners
  • State: Ohio
  • Country: United States
  • Dolomedes triton
  • Sex: MaleMale
  • Maturity: Immature
  • Attributes: Dorsal
  • City/Region: Raab Corners
  • State: Ohio
  • Country: United States
  • Dolomedes triton
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Dorsal
  • City/Region: Upper Holland
  • State: Pennsylvania
  • Country: United States
  • Dolomedes triton
  • Sex: MaleMale
  • Maturity: Immature
  • Attributes: Lateral
  • State: Michigan
  • Country: United States
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Dorsal
  • City/Region: Kissimmee, Osceola County
  • State: Florida
  • Country: United States
  • Dolomedes triton
  • Sex: MaleMale
  • Maturity: Immature
  • Attributes: Dorsal
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Dorsal, Eyes
  • City/Region: Pinellas County
  • State: Florida
  • Country: United States
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Dorsal
  • City/Region: Pinellas County
  • State: Florida
  • Country: United States
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Dorsal
  • City/Region: Orange County
  • State: Florida
  • Country: United States
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Eyes, Lateral
  • City/Region: Orange County
  • State: Florida
  • Country: United States
  • Dolomedes triton
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Dorsal
  • City/Region: Warm Springs Regional Fisheries Center
  • State: Georgia
  • Country: United States
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Eyes
  • City/Region: Groton, Middlesex County
  • State: Massachusetts
  • Country: United States
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Ventral
  • City/Region: Groton, Middlesex County
  • State: Massachusetts
  • Country: United States
  • Dolomedes triton
  • Sex: MaleMale
  • Maturity: Adult
  • Attributes: Dorsal, Eyes
  • City/Region: Kitty Todd Nature Preserve
  • State: Ohio
  • Country: United States
  • Dolomedes triton
  • Sex: FemaleFemale
  • Maturity: Adult
  • Attributes: Dorsal, Egg Sacs
  • City/Region: Saskatchewan
  • Country: Canada
  • Dolomedes triton
  • Maturity: Immature
  • Attributes: Dorsal, Eyes
  • State: Michigan
  • Country: United States
  • Dolomedes triton
  • Maturity: Adult
  • Attributes: Dorsal, Eyes
  • State: Louisiana
  • Country: United States

References and Further Reading

Various Research Papers

Scientific Diagrams and Keys for Identification

References for the Casual Reader

Species guide last updated: May 5, 2014

Follow Us

Search Spiders.us