Polypedates leucomystax (Four-lined Tree Frog): range, size and status

Polypedates leucomystax, the four-lined tree frog, is one of the most widely seen treefrogs of South and Southeast Asia, as comfortable in a rural garden as in untouched forest. It ranges from Northeast India, Myanmar, Thailand and Vietnam through southern China, including Hainan, and Peninsular Malaysia to the Philippines and the Indonesian archipelago (Borneo, Sumatra, Java, Sulawesi, Bali, Lombok, Sumbawa, Sumba, Flores and Timor among other islands), and has been introduced to Japan’s Ryukyu islands, including Okinawa, and to Papua.

Identification

The species is sexually dimorphic: males run about 37-50 mm in snout-vent length, while females are larger at about 57-75 mm. The body is moderately slender, egg-shaped and slightly flattened above, with a sharply pointed tail, with smooth skin on the upper surface. Colour is highly variable, with shades of grey, green, yellow, reddish or dark brown, usually mottled irregularly and often marked with four stripes running down the back — the pattern behind the common name. Some individuals show a distinct white spot at the tip of the snout. The eyes sit at the side of the head, and the webbed hind feet carry clear, large toe pads that help it grip leaves and branches well above the ground. During the breeding season, males give off a distinctive loud, duck-like call that carries across the pools where they gather to mate. Because the mottling and striping vary so much between individuals, colour pattern alone is a rough guide at best.

Habitat and range

The frog occupies subtropical and tropical dry and moist lowland forest, montane forest, shrubland, and seasonally wet or flooded grassland, alongside rivers, lakes, marshes and springs. It is just as much at home in heavily human-modified habitat, including rural gardens, urban areas, plantations and irrigated or seasonally flooded agricultural land, which helps explain why it has spread so successfully across the region and taken hold after being introduced to new islands.

Behaviour and breeding

Breeding is tied to the margins of shallow pools during the rainy season, where males call to attract females. A female deposits between 100 and 400 eggs in a protective foam nest that she attaches above the water, often on vegetation or a branch overhanging the pool. The eggs hatch within three to four days, and the tadpoles complete their early development inside the foam before dropping into the water below. From hatching to the end of metamorphosis takes roughly seven weeks, after which the young frogs disperse into the surrounding vegetation.

Conservation

The facts box gives the species’ IUCN category.

Similar species

Identification in the field is complicated by the fact that Polypedates leucomystax is now understood to be a species complex containing several cryptic lineages that look alike but are genetically distinct.