Meeting Abstract

P1-131    Color and Viscosity Analysis of Aplysia californica ink-opaline mixture Garza, A; Simonitis, LE*; Marshall, CD; Texas A&M University at Galveston; Texas A&M University at Galveston; Texas A&M University at Galveston garza_anahy@tamu.edu

Inking organisms let out a mixture of two chemicals: ink and a substance similar to mucus. Inking sea slugs release a mix of ink and opaline: a milky substance that becomes highly viscous when it comes in contact with water. In our preliminary studies, we observed a visual change in both viscosity and color in the defensive secretions of California sea hares (Aplysia californica), that suggest the ratio of ink and opaline varied over time. Ink and opaline secretions are known to be managed by two different neuronal controls. While previously described as all or nothing responses, prior studies have showed that inking responses are graded and based upon predation threat severity. Our objective was to quantify how the composition of the ink-opaline mixture changed by comparing the viscosity and color trends over time. We expected that over time, the sea hares will modify their secretion composition in response to persistent negative stimuli. We housed California sea hares in the Sea Life Facility. For each trial, we stimulated the organism by spinning around until it produced a defensive secretion. The California sea hares were placed in a resting container after releasing a defensive secretion, and on some days the sea hares produced successive samples. We then collected the ink-opaline mixtures for color and viscosity analysis. A total of ten California sea hares were inked every other day for a period of fourteen days. As hypothesized, we did observe changes in both color and viscosity among sequential inking events. While we observed a lot of individual variation of ink and opaline ratios over time, we were able to identify similar trends in how sea hares modified amount of ink and opaline in their secretions over time. This data supports that California sea hares inking responses are graded upon predation events and that they modify their defensive secretion throughout time.