Title
Model of jaw depression during feeding in **Astatotilapia elegans** (Teleostei: Cichlidae) : mechanisms for energy storage and triggering Model of jaw depression during feeding in **Astatotilapia elegans** (Teleostei: Cichlidae) : mechanisms for energy storage and triggering
Author
Faculty/Department
Faculty of Sciences. Biology
Publication type
article
Publication
Philadelphia, Pa ,
Subject
Biology
Source (journal)
Journal of morphology. - Philadelphia, Pa
Volume/pages
194(1987) :1 , p. 85-109
ISSN
0362-2525
Carrier
E
Target language
English (eng)
Full text (Publishers DOI)
Affiliation
University of Antwerp
Abstract
Suction feeding in Astatotilapia elegans occurs by a series of rapid, coupled movements of various head parts. The lower jaw rotates with respect to the neurocranium through an angle of 62° in less than 15 ms. The power requirements for jaw depression are calculated from a mathematical model and may reach a peak of ±4 watt in a 12-cm-long specimen. Data from the literature on mechanical output of fish muscle suggest that a muscular volume equal to 44% of the volume of the fish (= 45 cm3) should be required, if it is premised that movement and muscle shortening are directly coupled. Therefore, we assumed that storage and release of strain energy must be considered. The work demands for depression equal 0.014 J. The amount of energy storable in only three pairs of head ligaments can be estimated between 0.008 J and 0.05 J. The use of strain energy implies initial blocking and subsequent triggering of the movement. The position of the hyalomandibular connection, dorsal to the mandibular-suspensorial articulation, appears to be of crucial importance in balancing the forces of sternohyoideus and the body muscles. Triggering at the onset of jaw depression occurs by the contraction of the levator operculi. The line of action of the hyalomandibular connection is lowered beneath the jaw suspension, which raises the equilibrium of forces. Elastic recoil can occur thereafter.
Handle