Construction of earthen structure as a sexual signals in the fiddler crabs

Uca Earthen structure Habitat Sexual attraction.


  • Noor Us Saher
    Centre of Excellence in Marine Biology, Karachi University, Karachi, Pakistan.
  • Naureen Aziz Qureshi Faculty of Science and Technology, Government College, University, Faisalabad, Pakistan.
March 2, 2017


We studied the reproductive behavior and the construction of an earthen structure in the four species of fiddler crab with reference to their habitat. Males of the Uca sindensis and U. iranica inhibit on open mudflats, construct the pillar and semidome structures at or near to the burrows openings. These structures perform the function to attract females, who wandering on the surface between male burrows for mating as well as provide protection or hiding object against the avian predator to mates. There were no earthen structures were observed in U. urvillie and U. annulipes, which inhibit among the vegetation. The well-marked intersexual different arrangement of mudballs was observed in U. annulipes. The earthen structures (pillar and semidome) and mudballs arrangements help courting females to assess the quality of mate as well as internal conditions of the burrow.