Meeting Abstract

13.5  Thursday, Jan. 3  Locomotor ventilatory coupling in guinea fowl, Numida meleagris MARKLEY, J.S.*; CARRIER, D.R.; Univ. of Utah; Univ. of Utah markley@biology.utah.edu

Locomotor ventilatory coupling has been observed in several avian species during flight. Wingbeat has been shown to induce breath volume changes in two species (starlings and magpies; reviewed by Boggs, 2002), and shown to shorten flow reversal times, increasing the period of maximum flow (Boggs, 1997). Similar mechanisms may assist ventilation in running birds. We measured airflow at the mouth from guinea fowl running at three speeds. Transitions in the ventilatory airflow were always coupled with the step cycle at several stride to breath ratios described previously by Nassar et al. (2001). To determine the influence of stride on airflow at the mouth, we analyzed the “minibreaths” that occur with each step. Preliminary results indicate that induced mini-breaths increased airflow during both expiration and inspiration. More flow was induced out of the mouth than into it during expiration and more flow was induced into the mouth than out during inspiration. Overall, running steps induced 3% of inspiratory flow and 4% of expiratory flow. Additionally the transitions from inspiration to expiration and expiration to inspiration occur at consistent points of the step cycle. Coordinating these transitions with the stride cycle may be advantageous to create faster ventilatory transitions and reach higher flows faster as in flying birds.