User:Xl8815/Episesarma vesicolor

copied from Episesarma versicolor

Distribution

A mangrove inhabitant, it is found all over Southeast Asian countries such as Southern China, Hong Kong, Indonesia, Malaysia, Philippines, Singapore, Thailand, northern Australia and South Asian countries like Bangladesh, India and Sri Lanka.

Description

Male grows up to maximum length of 5 cm. Carapace square-shaped and relatively flat. Body color brown to brownish grey in carapace with violet colored outer surface of palm with proximal parts. Fingers are whitish. They also seem to possess an estimate of around 40 bony spine-like structures called tubercles. These are more pronounced in males and these tubercles like in other crab species that have them seemingly represent stridulatory organs used to create sound.

Ecology

The species is well distributed in mangrove regions, inhabits burrows at tree bases or sometimes within mounds created by Thalassina lobsters. E. versicolor favors the forest more than the Thalassina mound system in comparison to other species in the Episesarma genus. They are omnivorous, but feed primarily on calyx and leaves of water plants, mangroves and mangrove associates, usually at night. During high tides, they usually climb trees, as high as 6m up.

Feeding

Episesarma versicolor are omnivorous but primarily prefer eating leaves and calyx off of mangrove trees. They dig their burrows around the roots of mangrove trees and can utilize their arboreal abilities to climb on these roots when disturbed. They have been observed cutting leaf litters and bringing some fragments back to their burrows.To remove leaves from trees they tear off a section of the leaf with their claws and feed on those small sections they tear off. It is observed that leaves with previous damage from other herbivorous organisms are targeted by the crabs for feeding utilizing previous holes to tear off sections easier. At Segara Anakan Lagoon, Java, Indonesia, E. versicolor feed on various food sources including detritus, bark, leaves, and on roots, algae and animal matter to a lesser extent. Their diet adapts to the environment, which helps them survive when food sources are scarce or changing. When food is abundant, such as during a feeding experiment, they prefer leaves with a high amount of nitrogen compounds.

Behavior

Migration

E. versicolor burrow when the tide is low in day time, unless heavy rainfall forces them out of the burrows. When the tide is high, the larger crabs climb up trees, while smaller crabs stay burrowed. The crabs do not feed while they stay up on the trees, which indicates that they climb to avoid predators during high tide. Predators such as fish and hard-shelled crabs can enter the larger burrows of E. versicolor, which forces the larger individuals to climb up trees. However, while on the trees, E.versicolor are vulnerable to terrestrial predators and must avoid detection by staying motionless on the tree trunks.