Assessment of a new olfactometer for study of sensory ecology in small aquatic organisms.

All aquatic organisms rely on chemical stimuli at some point during their life cycles. These stimuli are typically associated with essential functions such as food-, mate-, or habitat-finding, or predator avoidance. Historically, research on sensory ecology and behavior of aquatic organisms has been conducted using two-channel choice flumes, which have many limitations when utilized on small organisms. Here, we describe functional features and results of pilot tests of an aquatic olfactometer, adapted from olfactometers used in studies on terrestrial arthropods, which eliminates these limitations. The initial implementation of this olfactometer is described. The structural integrity, hydrodynamics, and basic function of the olfactometer were tested and verified. The ability to clearly record the movements of a small organism within was also tested. Our experiments verify that the flow rate of water within the choice arena was accurate, water behaved as theorized in prior modeling, and chemical concentrations within each "zone" were distributed as expected based on computer simulations. We further show that video data could be obtained and analyzed using Ethovision XT to provide large amounts of raw data, including position, velocity, and acceleration, which can be used to investigate many potential questions associated with behavior. This olfactometer has the potential to become the new standard for research on chemotaxis and chemical ecology of small aquatic organisms. [ABSTRACT FROM AUTHOR]