Air breathing by the purple shore crab, Hemigrapsus nudus (Dana). 1. Morphology, behaviour, and respiratory gas exchange
The morphometrics of the respiratory system, voluntary emersion behaviour, and gas exchange during immersion and emersion were examined in the amphibious, intertidal crab Hemigrapsus nudus. The area of the gills (area = 993.8(body mass) super(0.83), where area is in square millimeters and body mass...
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| Published in: | Physiological zoology 1996-07, Vol.69 (4), p.785-805 |
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| Main Authors: | , , , , |
| Format: | Article |
| Language: | eng |
| Subjects: | |
| Online Access: | Get full text |
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| Summary: | The morphometrics of the respiratory system, voluntary emersion behaviour, and gas exchange during immersion and emersion were examined in the amphibious, intertidal crab Hemigrapsus nudus. The area of the gills (area = 993.8(body mass) super(0.83), where area is in square millimeters and body mass is in grams) is considerably reduced compared with that of aquatic species but similar to the gill areas of other amphibious crabs. The lungs occupy a large proportion of the branchiostegites and are highly vascularised, although the organisation of the vasculature is relatively unsophisticated compared with that of terrestrial species. Crabs voluntarily and regularly left the water, both in the field and in the laboratory, for short periods of 1-10 min, but also for extended periods of 8 h, and spent more time emersed than immersed. Oxygen consumption ( similar to 3.4 mu mol/h/g) and the respiratory exchange ratio were essentially unchanged by the voluntary cycle of emersion and immersion. Voluntary emersion was preceded by hyper-ventilation and tachycardia, but both ventilation and heart rate fell rapidly on exposure. On reimmersion there was pronounced hyperventilation and tachycardia that gradually gave way to normal values for immersed crabs. Body temperature rapidly equilibrated to ambient temperature on emersion and immersion, and in summer, fluctuations of body temperature up to 10 degree C are likely. |
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| ISSN: | 0031-935X 1937-4267 |