Atelopus varius
TAXONOMY
Phrynidium varium Lichtenstein and von Martens, 1856, Veragua, Panama.
OTHER COMMON NAMES
English: Harlequin toad.
PHYSICAL CHARACTERISTICS
These are often called harlequin frogs or toads because many of them are so brightly colored as to appear to be in a jester's costume. The coloration is usually a combination of markings of black and some starkly contrasting color such as yellow, green, orange, or red. In some populations the males and females are colored differently, in others they are similar. Males are about 1.06–1.57 in (27–40 mm), females 1.34–1.9 in (34–48 mm) in snout-vent length. Like most species of Atelopus, this one lacks a tympanum and cranial crests.
DISTRIBUTION
This toad is known from Costa Rica and Panama.
HABITAT
These toads inhabit humid lowland and lower montane forests.
BEHAVIOR
These diurnal toads may be seen actively moving across open areas as if impervious to predators; adults sleep at night on large flat leaves of vegetation over montane streams. The author has encountered as many as 50 individuals in an hour. Toads of the genus Melanophryniscus behave similarly. Harlequin frogs have exceptional homing ability. Field experiments showed that 31 of 44 individuals that were displaced 32.8 ft (10m) from their point of capture returned to within 3 ft (1 m) of that spot in a week. Some individuals were faithful to a particular boulder for two years. Male harlequin frogs have pronounced aggressive encounters. One may chase and pounce on another male and use his body to squash his opponent. Males may also signal each other by raising a front foot and waving it in a circular motion in the air, either before or after a battle. Interestingly, males will tolerate each other more in the dry season, when limited wet areas necessitates that they crowd together. When the rains come, aggression is more pronounced. In the species Atelopus zeteki and Atelopus varius, the extremely potent toxin tetrodotoxin has been found in the skin. This compound was named for the fugu or pufferfish (Tetraodon), from which it was isolated. At the least, tetrodotoxin makes the toad bad-tasting; at worst, it is lethal to the predator. There is a link between being diurnal, brightly colored, and toxic. A predator can easily spot this gaudy toad during the day, but the experience of grabbing this prey will be unpleasant. The predator learns to avoid potential prey that have these visual characteristics.
FEEDING ECOLOGY AND DIET
They are known to feed on a diverse set of arthropods, including flies, wasps, ants, caterpillars, and spiders.
REPRODUCTIVE BIOLOGY
There is apparently no courtship; the short buzzlike call serves a territorial function. Amplexus, as in other species of Atelopus, may last several days, with the female carrying the male around on her back. The eggs are completely cream-colored and are laid in strings, presumably in the streams in which the tadpoles are found.
The tadpole has an enlarged mouth and sucker that extends onto the belly. The tadpoles adhere to the undersides of rocks in swiftly flowing mountain streams.
CONSERVATION STATUS
Their diurnal habits make these toads easy to observe. But this has led to the unsettling realization that well-established populations of the Costa Rican Atelopus varius have mysteriously disappeared since the mid-1980s. However, the species is not listed on the IUCN Red List.
SIGNIFICANCE TO HUMANS
In the past, this animal was exported in large numbers for the pet trade. It apparently has been one of the victims of the worldwide decline of amphibians. Most populations in Costa Rica appear to be extinct.
