Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Using a variety of preparations, (intact birds during treadmill and overground walking/running and free-flight; decerebrate birds during electrically induced walking/running, passive wing flapping, and electrically induced wing flapping and "Active" flight), this thesis examines some of the mechanisms involved in the production and control of locomotor-respiratory coordination (entrainment) during alternating hindlimb locomotion (walking/running) and synchronous forelimb locomotion ("flight") in the Canada goose. Significant coordination of locomotor and respiratory rhythms was observed during both modes of locomotion in intact as well as decerebrate birds. While coordination of forelimb motion and respiration was virtually complete, coordination of hindlimb motion and respiration was sporadic. The level of entrainment during hindlimb locomotion, however, increased with increased stride frequency, rather than increased work rate, suggesting that proprioceptive feedback from the limbs is involved in the production of locomotor-respiratory entrainment. Further evidence for a role of proprioceptive feedback in the production of entrainment was provided by the entrainment of respiration by passive wing motion in decerebrate geese. Although feedback from the periphery was sufficient for the entrainment of wing motion and respiration, motor nerve outputs to the wing and respiratory musculature were also synchronized in paralyzed, decerebrate birds during electrically induced activity, in the complete absence of phasic afferent feedback. Thus, both feedback and feedforward mechanisms appear sufficient for the coordination of wing beat and respiration. / Science, Faculty of / Zoology, Department of / Graduate

Behaviour to increased water velocity is examined in fast stream fish (Otocinclus, Hypostomus, Pterygoplichthys, Chaetostoma and Gyrinocheilus) and a slow water form (Farlowella). Behaviour can be divided into two stages; resting and adhesion (Chapter I). In Otocinclus a third fin extension stage is apparent. Based on the slipping velocity of live and dead fish it is determined that Gyrinocheilus has the greatest station holding ability on a smooth perspex surface. This is attributed to a complete seal produced by its oral sucker lips (closed sucker). Station-holding ability is also examined on rougher surfaces. Slipping does not occur in any of the genera at water velocities up to 90 cm s⁻¹. Morphological adaptations (eg. oral sucker, pectoral fins, frictional pad and odontodes) that may contribute to increasing slipping velocity are examined. In Otocinclus these structures are analyzed using a Scanning Electron Microscope. Otocinclus is the only genera with the ventral dermal plates between the pelvic and pectoral fins organized laterally into a frictional pad. Drag on fish is directly measured with strain gauges and used to calculate drag coefficients (0.10 - 0.94; Chapter II). Drag coefficients for low fineness ratio (length/height < 10) forms at Reynold's numbers below 10⁴ compare poorly with literature values for technical bodies. Drag coefficients determined for fish are high due to roughness and interference drag produced by the fins. Using morphological measurements, dead slipping velocities, drag coefficients, static frictional coefficients and submerged body weight, lift coefficients (-0.55 - 1.23) calculated. Fast stream fish maximize slipping speed by having high frictional coefficients (0.67 - 0.95, on a smooth perspex surface), density (1.03 -1.10 g cm⁻³), rheotactic suction pressure (13 - 173 N m⁻²) and negative lift Although Farlowella has high density (1.129 g cm⁻³) and a low drag coefficient (0.23), its lift to drag ratio is high (6.71) and rheotactic suction pressures (2 - 27 N m⁻²) are low. In general Farlowella does not exhibit hydrodynamic, behavioural or morphological characteristics that enhance station-holding. / Science, Faculty of / Zoology, Department of / Graduate

Although frogs are recognized as accomplished swimmers, no detailed biomechanical study has been done. The hydrodynamics and mechanics of swimming, in the frog, Hymenochirus boettgeri, are investigated in this thesis. Hydrodynamic drag, of the body and splayed hind limbs of preserved H. boettgeri, was assessed by drop-tank experiments. Drag tests were also performed with the semi-terrestrial Rana pipiens. A comparison of their drag coefficients (CD) under dynamically similar conditions, suggests that jumping performance may not compromise the swimming ability of R. pipiens. Drag of the expanded foot of H. boettgeri, and acetate models thereof, was investigated by free fall drop-tank experiments, and a subtraction technique. The results of these methods and flow visualization experiments support the assumption that animal paddles can be treated as three dimensional flat plates, oriented normal to the direction of flow. Cine films were used to study swimming during the near-vertical breathing excursions of H. boettgeri. The acceleration of frogs throughout hind limb extension (power stroke), is distinct from other drag-based paddlers (eg. angelfish and water boatman), which accelerate and decelerate within the power stroke phase. The propulsive force generated during the power stroke of a single sequence (sequence 1) is calculated from quasi-steady drag (static-body drag measurements, see Chapter I) and inertial considerations. Additional components of the forcebalance, including the net effect of gravity and buoyancy, and the longitudinal added mass forces associated with the frog's body, are integrated to establish upper and lower bounds of the propulsive force. The propulsive force remains positive throughout extension. The validity of using static drag estimates to describe dynamic resistance is explored. Results from Chapter II suggest that simple drag-based models may not be sufficient to explain the swimming patterns observed. The right hind limb of the sequence 1 animal was modelled as a series of linked circular cylinders (the femur, tibiofibula, and metatarsal-phalangeal segments) and a flat plate (the foot). A blade-element approach was used to calculate the instantaneous drag-based and accelerative force components (parallel to the direction of motion) generated by hind limb flexion and extension. The negative thrust, generated by hind limb flexion, is probably responsible for the observed deceleration of the sequence 1 animal. Positive thrust is generated only during the initial stages of extension, almost exclusively by the feet. The impulse of the accelerative-based thrust far exceedes the impulse of the drag-based thrust. Negative thrust is initiated midway, and continues thoughout extension, despite the acceleration of the animal. Hind limb interaction, is thought to provide propulsive thrust for the latter half of the extension phase. A jet and/or ground effect may be involved. It is suggested that a combination of reactive, resistive and interactive forces are required to explain propulsion in H. boettgeri, and probably other anurans. / Science, Faculty of / Zoology, Department of / Graduate

I investigated the effects of food, crowding, and weather on the behaviour of the slugs, Arion ater and Ariolimax columbianus. Field experiments demonstrated that Arion based its migratory response on the density of conspecifics and the quality and quantity of available food. Migration was most rapid from areas of high slug density and scarce poor quality food. The migration response of Ariolimax was exclusively based on density. Although high slug density induced migration by this species, its rate of migration was lower than that of Arion. Migrating Arion ater were heavier than non-migrating slugs. There was no such relationship between body weight and locomotory or migratory ability of Ariolimax columbianus. Both species exhibited seasonal variation in their behaviour. Hot, dry weather during mid-summer curtailed their foraging and migratory activity. Cooler, wetter weather in late spring and late summer lengthened nocturnal activity periods. Average daily temperature and precipitation were poor predictors of migratory activity. Multiple regression analysis of hourly activity patterns and weather showed that, time of day, air temperature, and atmospheric moisture accounted for most of the variation in hourly nocturnal behaviour. Variation in slug density and food acceptability had no effect on population activity in Arion ater. However, the treatments did influence particular kinds of behaviour. Arion provided with poor food moved and rested more, but fed less, than slugs receiving good food. The effects of density were not significant. Poor food and high slug density increased the activity of Ariolimax columbianus. This effect was also evident in the component behaviours of total activity. Ariolimax moved, rested, and fed more in high density situations. These slugs fed more when good food was available, but the other behaviours were unaffected by this factor. On an hourly basis Arion ater's activity pattern appeared to be based on food acquisition. Over days and weeks, however, this species used both population density and food acceptability to decide to migrate. Ariolimax columbianus' hourly behaviour pattern was most closely related to the density of conspecifies. This response to density persisted over days and weeks, and was the most important factor affecting the migratory behaviour of these slugs. / Science, Faculty of / Zoology, Department of / Graduate

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