The predatory stomatopod Hemisquilla ensigera californiensiswas captured at 10-20 m depths off California and transferred to an observation tank with artificial burrows similar to those observed in the field. The animals were maintained under a 1OL:140 light-dark cycle and monitored on a 24-hour basis using a time-lapse video recorder. Infrared lamps were used for observations within the burrow and at night. Metabolic rates, as a function of oxygen tension, were measured in respirometry chambers using polarographic oxygen electrodes.

This species is a near complete oxyconformer, so aerobic metabolism is strongly depressed at low oxygen levels, yet the animals remained active within the burrow even under these conditions. H. ensigera builds a blindended burrow that would be difficult to aerate by pumping oxygenated water into the burrow. The animal further complicates the possibility of water exchange by capping off the burrow for up to three-fourths of the daily cycle. Finally, this mantis shrimp was not observed trying to actively pump oxygenated water into the burrow and often remained at the far end of the burrow with little regard for the better-oxygenated water near the entrance. This is in contrast to other known burrowing shrimp, such as Upogebia pugettensis and Callianassa californiensis, which also remain in hypoxic burrows but they are oxyregulators and often become dormant in hypoxic conditions or aerate their burrows by pumping oxygenated water into them. H. ensigera does not fit well into either the "environmental anaerobiosis" or "facultative anaerobiosis" categories. During times of relative anoxia within the burrow the animal maintains a moderate level of activity instead of the quiescence normally expected under hypoxic conditions.

LLU Discipline





Graduate School

First Advisor

David L. Cowles

Second Advisor

Leonard Brand

Third Advisor

Ronald Carter

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Shrimps -- California; Decapoda (Crustacea) -- Behavior.



Page Count

vi; 44

Digital Format


Digital Publisher

Loma Linda University Libraries

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This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


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Loma Linda University. Del E. Webb Memorial Library. University Archives

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