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Taxonomic Classification
Kingdom: Animalia
Phylum: Arthropoda
Sub-Phylum: Chelicerata
Class: Arachnida
Order: Araneae
Family: Pisauridae
Genus: Dolomedes
Species: Triton
Morphology/Basic Anatomy
Dolomedes Triton is a fairly large spider with very distinctive markings. They are grayish brown in color with pale cream colored lines running down the sides of its cephalothorax. There are also little white specks or dots scattered along the top of its body. However, the spider gets its name from the six dark spots that are arranged in a circle that are on the spiders belly. The spider has eight eyes that are all equal in size along with three tarsal claws. Dolomedes tritons do not have a cribellum (a silk spinning organ). This spider, like many other spiders, show sexual dimorphism where the females are larger than the males. A female Dolomedes triton's body length can be anywhere from 0.59-0.79 inches, while the males are only 0.35-0.51 inches long.
Geographic Range
Six Spotted Fishing Spiders are native to the western hemisphere. They can be found along the south Atlantic coastline, the coastal New England states, North Dakota, and Texas. The fishing spider also inhabits moist environments of Central and South America.
Habitat
Dolomedes tritons are semi-aquatic. They live in moist and wetland habitats which includes ponds, lake shores and streams and their nearby vegetation. They tend to stay close to rocks or structures that are located near a body of water, such as a boat dock. Fishing Spiders are actually often referred to as "dock spiders" because boat docks are one of their favorite hang out spots.
Fishing Spider submerged under water
Behavior/Diet/Hunting
The Six Spotted Fishing Spider hunts for its prey on the waters surface. They walk and scamper along the surface of the water and are able to dive under the water up to 18 centimeters (71 inches). These spiders are able to pinpoint the exact location of their prey by sensing the concentric surface waves while standing upon the water. Dolomedes tritons also have excellent eye site that make them such successful hunters, they can see ans sense food both above and below the water's surface. They also have been seen dipping their front legs in and out of the water to lure fish towards their direction. With this species being diurnal, they only hunt during the day time. The fishing spider will sit on top of the water for hours on end while it waits to be stimulated by its prey. Six Spotted Fishing Spiders have a wide range diet which allows them to be able to eat up to five times its own weight in a single day. Their diets consist of insect larvae, insects that are blown and floating on the water's surface, tadpoles, aquatic vertebrates such as frogs, and several types of small fish.
Dolomedes Triton has caught a fish
Locomotion
Dolomedes tritons are not only able to dive under the surface of the water, but they can also propel themselves across water whether they chose to go slowly or fast. "Sailing" is one way that a fishing spider can get around. To sail they lift their front pair of legs off of the surface and they let a gust of wind or a slight breeze blow them across the water. When doing this though, they do not have any real control over their speed or distance. "Rowing" is the most common for of movement. When standing on the water surface, each of the spiders legs create a dimple on the surface. When the spider strokes the third then second pair of legs backwards, the water is pushed towards the posterior end of the spider which in turn moved the spider forward along the water. However, if the spider feels as if he is in danger or needs to chase after potential prey, they are able to "gallop". At times this allows the spider to become completely airborne. With this method of transportation the spider slices the water with the tips of its legs very fast. This elevates the body above the surface resulting in incredible speeds of 3 feet per second.
Reproduction & Life cycle
Male fishing spiders take a great risk when trying to mate. Female Dolomedes tritons demonstrate cannibalism if males fail to impress them or she is just especially hungry that day. Anytime from June to September when egg production generally occurs is when male fishing spiders will attempt their courtship rituals. During a mating ritual, the male spiders will create rhythmic surface waves to catch the females attention and gradually move closer until they are touching legs. If a female is impressed with the male they will proceed with mating. The female spider will then produce a silk egg sac which she will carry around the front of her jaw until she thinks the eggs are just about to hatch. Once she knows the eggs will soon hatch, she will spin a "nursery web" in a safe place that is usually guarded by leaves and sticks providing a sheltered environment. The female drops the egg sac into the nursery and will stay and guard them until about one week after they have hatched. About one week after they have hatched is when they are ready to disperse themselves out into the world to live a life for themselves, no longer needing mom's help or protection.
Female Spider with egg sac
Fun Facts About Fishing Spiders
They were named after the mythological Greek god Triton who is the messenger of the big sea and the son of Poseidon.
Six Spotted Fishing Spiders have a positive economic importance to humans. They play an important role in keeping the insect population of the world under control.
Their bodies are covered with small hairs that allows them to stay dry, even when submerged under water.
Their two main predators are birds and snakes
Video of a Dolomedes Triton Hunting for Fish
https://www.youtube.com/watch?v=hgUnRRep5YQ
Works Cited
http://www.sciencedirect.com/science/article/pii/S0003347200916798
https://link.springer.com/article/10.1007/BF00299502
http://www.sciencedirect.com/science/article/pii/S0003347287801008
Figiel, Chester R., and Gary L. Miller. “Effects of Fish on the Growth and Survival of Two Fishing Spider Populations (Dolomedes Triton; Araneae, Pisauridae).” The Journal of Arachnology, vol. 22, no. 3, 1994, pp. 185–189. JSTOR, JSTOR, www.jstor.org/stable/3705420.
Spence, John R., et al. “Effects of Food Limitation and Sexual Cannibalism on Reproductive Output of the Nursery Web Spider Dolomedes Triton (Araneae: Pisauridae).” Oikos, vol. 75, no. 3, 1996, pp. 373–382. JSTOR, JSTOR, www.jstor.org/stable/3545877.
Roble, Steven M. “Submergent Capture of Dolomedes Triton (Araneae, Pisauridae) by Anoplius Depressipes (Hymenoptera, Pompilidae).” The Journal of Arachnology, vol. 13, no. 3, 1985, pp. 391–392. JSTOR, JSTOR, www.jstor.org/stable/3705324.
Bleckmann, Horst, and Jerome S. Rovner. “Sensory Ecology of a Semi-Aquatic Spider (Dolomedes Triton): I. Roles of Vegetation and Wind-Generated Waves in Site Selection.” Behavioral Ecology and Sociobiology, vol. 14, no. 4, 1984, pp. 297–301. JSTOR, JSTOR, www.jstor.org/stable/4599681.
Bleckmann, H. & Barth, F.G. Behav Ecol Sociobiol (1984) 14: 303. https://doi.org/10.1007/BF00299502
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