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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Behaviour associated with shell competition in the urchin crab, Dorippe quadridens

Shen, Chen-Chen 15 August 2006 (has links)
The tips of the fourth and fifth pairs of pereiopods of the Dorippe quadridens are hook-liked that enable them to carry some objects. Many researches have studied the carrying behavior of this crab, but very few on its behavior related to competition for resource (i.e., the objects such as shells). This study was designed (1), to investigate the effects of body size, autotomy (loss of these pereiopods), and order in occupation of shell on the final passion of the shell (i.e., the resource), and (2) selectivity of shell. Dorippe quadridens often chose the shells larger than its pereiopod width. Weights of the selected shell were not related to the body weight of the crabs; they preferred larger but lighter shells. Probability of finding a shell did not correlated either with body size or the condition of the pereiopods. Under an asymmetric contest for shell, a shell owner stood a higher chance of holding on to the shell against an invader which tried to rob the shell. This situation did not replay in a symmetric contest. A small shell owner and a smaller invader for shell behaved differently against their larger competitor as contrast to a symmetric contest for shell. Duration of fight for shell was related to the size differences of the contestants. Under the symmetric-contest condition, durations of fight in pairs of variable sizes remained relatively constant that this parameter was not affected by the sizes of the contesting pairs. It appeared that the D. quadridens made decision on the fighting strategy by assessing the conditions of the opponent and themselves; they would fight against or escape from the opponents under different conditions. The behavioral performances observed in this crab species conform to the definition of interference competition.

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