Abstract
Knowing the functionality and capabilities of masticatory apparatuses is essential for the ecological classification of jawed organisms. Nevertheless insects, especially with their outstanding high species number providing an overwhelming morphological diversity, are notoriously underexplored with respect to maximum bite forces and their dependency on the mandible opening angles. Aiming for a general understanding of insect biting, we examined the generalist feeding cockroach Periplaneta americana, characterized by its primitive chewing mouth parts. We measured active isometric bite forces and passive forces caused by joint resistance over the entire mandibular range with a custom-built 2D force transducer. The opening angle of the mandibles was quantified by using a video system. With respect to the effective mechanical advantage of the mandibles and the cross-section areas, we calculated the forces exerted by the mandible closer muscles and the corresponding muscle stress values. Comparisons with the scarce data available revealed close similarities of the cockroaches’ mandible closer stress values (58 N/cm2) to that of smaller specialist carnivorous ground beetles, but strikingly higher values than in larger stag beetles. In contrast to available datasets our results imply the activity of faster and slower muscle fibres, with the latter becoming active only when the animals chew on tough material which requires repetitive, hard biting. Under such circumstances the coactivity of fast and slow fibres provides a force boost which is not available during short-term activities, since long latencies prevent a specific effective employment of the slow fibres in this case.
Highlights
Feeding is one of the basic manifestations of life. It is generally implemented by the action of specialized apparatuses, which are characterized in many vertebrates and arthropods by jaws that interact with each other
For the largest group of terrestrial arthropods contributing a major part of the faunal biomass, reliable determinations of bite forces over the functional angular range are almost completely lacking, though studies regarding behaviour and energetics of feeding in ants and other durophagous species showed extraordinary high metabolic rates when cutting up hard food [8]
As an attempt to make at least biting physiology more accessible, here we provide muscle forces and muscle stress values of the mandible closer muscle of the general feeder P. americana, and compare these values with those of other species
Summary
Feeding is one of the basic manifestations of life. In higher taxa, it is generally implemented by the action of specialized apparatuses, which are characterized in many vertebrates and arthropods by jaws that interact with each other. For the largest group of terrestrial arthropods contributing a major part of the faunal biomass, reliable determinations of bite forces over the functional angular range are almost completely lacking, though studies regarding behaviour and energetics of feeding in ants and other durophagous species showed extraordinary high metabolic rates when cutting up hard food [8]. These results, in turn, suggest strong bite forces being a common characteristic for insects
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
