Meeting Abstract
There is typically little variation in the structure of nervous systems of closely related species, but often variation is found in the size, number and location of individual neurons. To explore the variation of nervous systems among several gastropod species, GABA-immunoreactive (GABA-IR) cells were identified in the grey field slug Deroceras reticulatum. GABA-IR cells were chosen in order to compare results to previously unpublished data from the garden snail Cornu aspersum and the scarlett-backed taildropper slug Prophysaon vanattae. The three gastropods belong to the Stylommatomorpha clade and are found in the Pacific Northwest. We expected to find same number of GABA-IR neuron clusters across species, but expected to find variation in the number of cells within those clusters across the three species. In all three species, GABA-IR clusters were found in both the cerebral ganglia and in the fused pedal, plural, visceral and parietal ganglia. We found no significant difference in the number of clusters in the cerebral ganglia (p = 0.71; α = 0.05; t-test) nor the pedal ganglia (p = 0.50; α = 0.05) between D. reticulatum and P. vanattae. However, there was a significant difference between the number of cells per cluster across D. reticualtum and P. vanattae. The number of cells per cerebral cluster in D. reticulatum (8.4 ± 0.7) was less than P. vanattae (12.7 ± 1.0; p < 0.0001). Similar results were found for the number of cells per pedal ganglia (p < 0.0001).
