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Alpheus parvirostris

Green banded snapping shrimp

Aidan Janetzki (2013)

  

 

Fact Sheet

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Summary


Physical Description


Size


External Anatomy


Ecology


Habitat


Life History & Behaviour


Snapping Effect


Moulting


Egg Development


Internal Anatomy & Physiology


Evolution & Systematics


Biogeographic Distribution


Conservation & Threats


References & Links

Snapping Effect

Without a doubt the most distinguishing feature of snapping shrimp and therefore Alpheus parvirostris is the ability to create a loud snap by rapidly closing its larger chela.  The snapping chela consists of a rounded plunger located on the dactyl which has a matching excavation or fossa located on the fixed finger (Debelius 2001) When closed it displaces the water around its chela with such speed that it is though to exceed cavitation conditions (bubble formation) (Versluis et al. 2000).  However Versluis et al.  suggests that the loud snap made by the shrimp is not a result of the claw closure but in fact occurs when cavitation bubble collapse occurs. 

Step by step process:
  1. Initially, the chela is locked into into position from muscle contraction
  2. Tension builds up until a second muscle also contracts
  3. At this point, the chela rapidly closes shut
  4. Results in a high velocity water jet from the displacement of water around the dactyl
(Versluis et al. 2000)



Photo of Alpheus Parvirostris largest chelae, with the claw in an open (locked) state.  Note the rounded plunger (centre of photo) and its matching excavation (above plunger).  Original Photo Aidan Janetzki 2013.  


Snapping shrimp are thought to 'snap' for two reasons.  Firstly, they have been observed to stun or kill small fish by snapping their large chela in the fishes vicinity.  The fish are then preyed upon, and make up a stable diet for many species of snapping shrimp (Versluis et al. 2000).  Secondly, snapping shrimp use their snapping mechanism as a defence mechanism either against predatory organisms such as errant annelids or against other shrimp of the same species.  Such behaviour was observed on Heron Island, where shrimp were placed in a confined area, such that their numbers were much more concentrated than would would likely be the case in the wild.  This action brought upon regular snapping , particularly amplified as the females were currently carrying eggs and were likely to be more aggressive towards other shrimp.  


 
Video of Alpheus parvirostris creating the snapping sound. Original Video Aidan Janetzki 2013.

Classification

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