Males of several fiddler crab species sometimes construct sand structures (referred to as “hoods” in Uca lactea) at the entrance to their burrow, to which they attract females. Like the bowers of bowerbirds, sand structures of fiddler crabs are external ornaments that exist physically apart from the animals. Despite the mating benefit gained by possessing a structure, many males do not construct structures and some males even destroy their own structures. Structure destruction cannot be explained by the time and energy costs associated with structure construction or maintenance. This implies that the possession of a structure alone can be costly. In the present study on U. lactea, I experimentally planted hoods at the burrows of males that did not have hoods, and compared their frequency of hood destruction with that of control males (builders whose hoods were replaced with those of other males). Non-builders destroyed planted hoods more frequently than control males. Females, which do not construct hoods, also destroyed experimentally planted hoods more frequently than control males. Hoods are able to attract females, but the possession of hoods may incur some costs for crabs, probably because hoods also attract males and non-receptive females. Hence, only males that can afford the costs are likely to construct hoods.