Meeting Abstract

35.4  Sunday, Jan. 5 08:45  Smelling the difference: How do the size and shape of the olfactory recess relate to olfactory airflow? EITING, TP*; PEROT, JB; DUMONT, ER; UMass Amherst; UMass Amherst; UMass Amherst tpeiting@bio.umass.edu

Many mammals house a blind recess in the back of their nasal fossa, the olfactory recess. Histological examinations and airflow modeling of the nasal fossa have been based on only a handful of fairly distantly related mammalian species. However, histological work that has investigated groups of closely related species has shown substantial variation in the morphology of the nasal fossa, including the olfactory recess. One such group is the New World leaf-nosed bats (Phyllostomidae). Within this family some species have less than 10% of the olfactory epithelium located within the olfactory recess, while in others it is more than a third. These different percentages stem from differences in morphology of the olfactory recess; those species that have low percentages have reduced and fairly simple olfactory recesses, while those with higher percentages have enlarged and more complex olfactory recesses. Based on previous modeling studies, we expect species with enlarged olfactory recesses to have lower rates of flow over their olfactory epithelium during inhalation, and to sequester more newly-inhaled air from the air currents during exhalation. Initial results from airflow models of four species of phyllostomid bats show little variation in patterns of airflow during inhalation and exhalation. Instead we find that changing flow rate within a species produces different patterns of flow throughout the nasal fossa, including the olfactory recess. These findings suggest that the size and morphology of the olfactory recess alone do not explain differences in olfactory airflow.