Mantella aurantiaca

Geographic Range

Mantella aurantiaca occupy the montane pandanus forests around Andasibe and they are typically found in isolated patches ranging throughout southeastern Madagascar. (Staniszewski, 1997)

Habitat

Golden mantellas are considered an "upland" species, due to the fact that they are found at an altitude of about 900 meters. The climate is typically moist, humid and temperate. They usually inhabit mossy or grassy mounds of forest debris that border shallow swampy waters. (Staniszewski, 1997)

  • Range elevation
    900 (high) m
    2952.76 (high) ft

Physical Description

Adult snout vent lengths (SVLs) are typically 1.25 inches, although 1.5 inch SVLs have been reported. These frogs exhibit brilliant golden-orange coloration that is impossible to miss. They occasionally have red flash marks on the inner portion of the hind legs. The eyes of this species are jet black. The legs are very short with distinct adhesive disks found on the fingers and toes (Badger, 1995). There is sexual dimorphism. Males are generally smaller, slimmer and more angular in build than females, and tend not to call as much as other species of male mantellas. The male's ventral surface is lighter in color and therefore causes the seminiferous ducts (narrow pair of pale lines) to be visible. These ducts hava a dual purpose in males, carrying both sperm and urine. Females also have these ducts but they are, for the most part, concealed by the uterus and oviducts. The ducts in females do not carry sperm but they still function in urine transportation (Staniszewski, 1997). (Badger, 1995; Staniszewski, 1997)

  • Sexual Dimorphism
  • female larger
  • sexes shaped differently
  • Average length
    3.175 cm
    1.25 in

Development

Eggs undergo rapid terrestrial development (2-6 day hatch period) and the newly hatched tadpoles either wriggle to the nearby water source or are washed into the water by storms (Bartlett, 1996). Tadpoles typically metamorphose into froglets 6 to 8 weeks after hatching. The tadpoles are primarily herbivores, feeding on algae and detritus, although some meat matter may be incorporated into the diet. Once the tadpoles become froglets, they are usually 10 to 14 mm in SVL and begin feeding on the more typical adult insect (springtails and small aphids) (Staniszewski. 1997). Sexual maturity is reached in 12 to 14 months. (Badger, 1995; Staniszewski, 1997)

Reproduction

Males use a call consisting of a series of short notes, with three clicks per note, to attract female mates. Territorial aggression does occur in both sexes during this time, but especially in males. Intruders are sometimes grabbed around the upper body or head and are typically pushed away. The actual courtship process of this species is rather secretive and usually takes place under bark, logs, or rocks. If a non-gravid femaile is amplexed, she will flick her legs and back flip until the male releases her. (Badger, 1995; Staniszewski, 1997)

Mating usually occurs when there has been an abundant amount of food available and when the first substantial rain comes. Once amplexus is successfully underway, a suitable egg-laying site will be searched for. These sites usually include damp moss, crevices in logs, underneath damp bark or rocks and are always adjacent to a water source (Staniszewski, 1997). Clutches consist of 12 to 30 eggs, 2 to 3 mm in diameter and are immediately fertilized by a male, although fertilization can occur up to 2 days later and by multiple males. (Badger, 1995; Staniszewski, 1997)

  • Breeding interval
    Breeding occurs when food is abundant, depending on rainfall.
  • Breeding season
    Breeding is opportunistic, occurring when conditions become favorable.
  • Range number of offspring
    12 to 30
  • Range age at sexual or reproductive maturity (female)
    12 to 14 months
  • Range age at sexual or reproductive maturity (male)
    12 to 14 months

Once the eggs are laid, parent golden mantellas have no further involvement in the development of their young. (Badger, 1995; Staniszewski, 1997)

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female

Lifespan/Longevity

Mantella aurantiaca typically has a life span of 8 years.

Behavior

Mantella aurantiaca are usually colonial in nature, living in groups scattered throughout southeastern Madagascar. The male to female ratio in the wild is about 2 to 1 and is therefore reflected in the composition of these colonies, males being more plentiful than females. They are diurnal (day-active) in nature, hunting basically all day for food. Makes do have a puzzling behavior in that they are particularly reluctant to call, compared to other species of mantellas. A reason for this has not yet been positively identified, although it may have something to do with not wanting to draw attention from predators to itself or it may be a way of conserving vital energy. (Badger, 1995)

Communication and Perception

Golden mantellas use auditory cues, and may also use visual or chemical cues to communicate. They use their vision to locate prey.

Food Habits

Mantella aurantiaca are entirely insectivorous. A diet commonly consists of termites (Isoptera), ants (Formicidae), fruitflies (Drosphila), and just about any other arthropod that can be fit into the mouth. Golden mantellas are known for attempting to eat anything, even if the taste is repulsive (Bartlett, 1996). (Bartlett, 1996)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods

Predation

The brilliant colors exhibited by M. aurantiaca can be attributed to a phenomenon called aposematic coloration, where toxic or dangerous animals use bright colors or marking to advertise their toxicity to potential predators. Golden mantellas have toxic skin secretions, protecting them from most predators. (Badger, 1995)

Economic Importance for Humans: Positive

Many individuals are captured from the wild for the pet trade while some are now captive bred.

Economic Importance for Humans: Negative

Golden mantellas are toxic, although humans would not typically be exposed to this toxin if they are not harassing these frogs.

Conservation Status

Several human-caused factors are causing a decline in native populations of the golden mantella. Overcollection for the pet industry, introduced predatory species, major deforestation in Madagascar and human encroachment are all among the leading causes fueling this raging decline.

Other Comments

Mantella aurantiaca was, for many years, classified as a member of the posion arrow genus Dendrobates. Their phylogenetic position has been somewhat unstable over the years.

Contributors

Thomas Loch (author), Michigan State University, James Harding (editor), Michigan State University.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

acoustic

uses sound to communicate

aposematic

having coloration that serves a protective function for the animal, usually used to refer to animals with colors that warn predators of their toxicity. For example: animals with bright red or yellow coloration are often toxic or distasteful.

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.

carnivore

an animal that mainly eats meat

diurnal
  1. active during the day, 2. lasting for one day.
ectothermic

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

external fertilization

fertilization takes place outside the female's body

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.

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.

insectivore

An animal that eats mainly insects or spiders.

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

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.

oviparous

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

poisonous

an animal which has a substance capable of killing, injuring, or impairing other animals through its chemical action (for example, the skin of poison dart frogs).

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

sedentary

remains in the same area

sexual

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

social

associates with others of its species; forms social groups.

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

References

Badger, D. 1995. Frogs. NY: Barnes and Noble, Inc.

Bartlett, R. 1996. Frogs, Toads, and Treefrogs. NY: Barron's Educational Series.

Staniszewski, M. 1997. "Mantella FAQ" (On-line). Accessed 11/03/99 at http://www.amphibian.co.uk/mantella.html.