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Patterns of heart and scaphognathite activity in the crab Cancer magister

1977; Wiley; Volume: 202; Issue: 1 Linguagem: Inglês

10.1002/jez.1402020105

1097-010X

D. G. McDonald, B. R. McMahon, Chris M. Wood,

Crustacean biology and ecology

Abstract The respiratory system of the crab Cancer magister has been investigated with long‐term measurements of the activity in the heart and scaphognathites of unrestrained animals settled on a natural, sandy substrate. Although crabs generally remained motionless in the experimental apparatus, except while in the dark, they initially exhibited a high degree of respiratory activity; the rates of forward pumping by the scaphognathites exceeded 90/minute, reversal incidence was less than five reversals/10 minute and heart rate was constant. Subsequently both the heart rate and the forward pumping rates of the scaphognathites declined, incidence of reversals increased and spontaneous pauses by the heart and scaphognathites began to occur. Eventually one scaphognathite ceased pumping for prolonged periods. Possible roles for reversals, pauses and unilateral pumping are discussed.