Ambystoma lateraleBlue-spotted Salamander

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Geographic Range

Blue-spotted salamanders are found from eastern central North America and stretch in a broad band across to the Atlantic Provinces and northern New England. They are found around the Great Lakes and west as far as central Manitoba. They reach as far north as James Bay, Ontario (Collicutt 1999).

Habitat

The blue-spotted salamander lives in deciduous and coniferous forests. They are most abundant in moist woodlands with sandy soil. They differ from other salamanders in that they are found above ground throughout the warmer months (Harding 1997). During the day they stay undercover out of the direct sunlight. They spend the summer and fall in damp forests, searching for food at night (Nova Scotia 1999).

  • Aquatic Biomes
  • lakes and ponds

Physical Description

Length: 10-14cm.

Blue-spotted salamanders have a long tail that is approximately 40% of its body length (Collicutt 1999). The salamander's tail is broadly oval at the base and compressed towards the tip. It is fleshier than A. jeffersonianum (Minton 1972). They also have a slimmer body than the tiger salamander A. tigrinum (Collicut 1999). Their feet have relatively long toes (Conant and Collins 1998). They are given their name for the bluish-white spots and flecks on the tides of the trunk and tail and also sometimes on the back. Their skin is bluish-black (Conant and Collins 1998). The spots are also on their limbs and belly (Harding 1997). The belly may be either black or a lighter shade than the dorsum, but the vent is usually black (Harding 1997). There is some slight size difference between the males and the females. The males tend to be slightly smaller than the females, the males also have a longer more flattened tail (Harding 1997). The larvae of blue-spotted salamanders vary in appearance. When the larvae are small and relatively young they have broad tail fins and external gills for living in the water (Collicutt 1999). But once they have developed all four legs they appear to be dark brown, olive or gray on the upper surface with dark mottling on the fail fins. They also may have dull yellow blotches on the dorsum or yellowish stripes down each side of the back. The belly is lighter and unmarked (Harding 1997).

Development

Reproduction

The life span of a blue-spotted salamander is unknown (Collicutt 1999). Both male and females reach maturity at about 2 years of age (Harding 1997). The salamander breeds in woodland ponds and ditches (Conant and Collins 1998). They breed in April in small ponds. The female lays as many as 500 eggs individually at bases of sticks, plants or rocks. The eggs take about 1 month to hatch, and when they hatch they have well-developed eyes, mouth, external gills, and broad tail fins. At two weeks old, the front legs form and at 3 weeks the hind limbs are formed. As they get older they look like tiny adult salamanders except they have broad tail fins and external gills. Between 3-5cm in length they transform into the adult form and leave the pond. When they transform they loose their external gills and tail fins and develop the adult coloration (Collicut 1999). They transform in late summer (CCIW 1999).

Behavior

Blue-spotted salamanders breed in the spring. They migrate to the breeding ponds when warm evening rains start and warming temperatures and rapid snowmelt. The courtship process has a brief stage where the male nuzzles and nudges the female with his snout. Then the male crawls above the female and grabs her behind the front legs and he rubs his chin on her head and snout. This position may be maintained for several hours, rising to the surface occasionally. The male eventually releases the female and deposits a spermatophore in front of her. The male leads her to the spermatophore and the female picks it up with her cloaca (Harding 1997). They also have some defense mechanisms. The small size of the body enables the salamander to hide well, and the blue spots help to break up the outline of the body. They also have granular glands that are mostly concentrated on their tail. These glands produce a milky noxious liquid that is secreted when it is threatened. The blue-spotted salamander holds the tail up and curved over the body when it is alarmed. If the predator attacks the tail, it gets the sticky secretion in its mouth (Collicutt 1999).

Food Habits

The Blue-spotted salamander is a carnivore. The adult eats worms, snails, slugs, insects, centipedes, spiders and other invertebrates. The larvae eat small aquatic invertebrates such as water fleas (cladocerans), copepods, insects and insect larvae, especially mosquito larvae (Harding 1997). The diet suggests that the feeding ground is beneath leaf litter in forests (Collicut 1999). In captivity, blue-spotted salamanders survive on 1 worm a week (Collicut 1999).

Economic Importance for Humans: Positive

Blue-spotted salamanders consume many mosquitoes each year (Harding 1997).

Conservation Status

Due to the loss of wetlands and the destruction of forests, the salamanders are threatened. However, there is no evidence of decline in the blue-spotted salamander as of yet (CCIW 1999). Blue-spotted salamanders are more tolerant to human disturbances than other salamanders. They still persist in fragmented forests (Harding 1997).

Other Comments

The blue-spotted salamander hybridizes with the spotted salamander, the Jefferson salamander, and the tiger salamander. The hybrid between blue-spotted salamander and Jefferson salamander is called A. platineum. It is a unisexual clonal triploid. This hybrid reproduces gynogenetically. Gynogenetic reproduction is where sperm from a host species is needed to activate the egg development but makes no genetic contribution (Spolsky 1992). The hybrid species are dependent upon one of the parental species.

Contributors

David Armitage (editor), Animal Diversity Web.

Melissa Donato (author), Michigan State University, James Harding (editor), Michigan State University.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

References

"The Canada Centre for Inland Waters (CCIW)" (On-line). Accessed November 6, 1999 at http://www.cciw.ca/ecowatch/dapcan/tour/glossary/bss/bss2.htm.

Collicutt, D. 1999. "Nature North Zone" (On-line). Accessed November 6, 1999 at www.pangea.ca/nnz/spring/creature/bluespot/Fblspot.html.

Conant, R., J. Collins. 1998. Reptiles and Amphibians in the Eastern/Central North America. New York: Houghton Mifflin Company.

Harding, J. 1997. Amphibians and Reptiles of the Great Lakes Region. Michigan: The University of Michigan Press.

Minton, S. 1972. Amphibians and Reptiles of Indiana. Indiana: The Indiana Academy of Science.

Spolsky, C., C. Phillips, T. Uzzell. 1992. Gynogenetic Reproduction in Hybrid Mole Salamanders. Evolution, 46(6): 1935-1943.