The feeding ecology of Sesarma plicata(Grapsidae:Sesarminae),the most abundant crab species in a mangrove forest dominated by Kandelia candel at Jiulongjiang Estuary,China,was investigated through field and laboratory experiments.Feeding preference and consumption rates were determined on mature,senescent and decomposed leaves of Kandelia candel,Bruguiera gymnorrhiza and Aegiceras corniculatum.In the laboratory,S.plicata preferred leaves of K candel over those of B.gymnorrhiza and A.corniculatum,and consumed significantly more decomposed leaves than mature and senescent ones,irreespective of crab size.Field experiments with limited power failed to reveal detectable species preferences despite more consumption of K.candel,but decomposed leaves of each species were again preferred.Leaf characteristics associated with preference changed with plant species and leaf state.Low tannins and high water contents charactetized the preferred state(decomposed)of leaves.Species preference was signifieantly and negatively related to crude fibers and C∶N ratios for mature leaves,and crude fibers for senescent leaves,but significantly and positively related to water content for decomposed leaves.Leaf consumption rates averaged for all leaf categories from laboratory no-choice feeding experiment were 0.101,0.055 and 0.017 gDW ind-1 d-1 for large,medium and small crabs,respectively.In this foist,mean density of S.plicata was 20.5 ind m-2 as assessed by a manual catching method.Leaf litter removal rate by sesannid crabs was about 1.33 gDW m-2 d-1 in April 2006,accounting for 88.7% of daily leaf litter fall.The leaves removed by crabs were grazed on the sediment surface or taken into crab burrows,shredded and stored before being eaten.