Chemosensory and behavioral ecology of the dipsadid snakes: Contia tenuis, Diadophis punctatus, and Hypsiglena chlorophaea

While much is known about the behavior of many groups of squamate reptiles, including several medium to large bodied snakes (e.g. natricines and viperids), we know very little about many small, cryptic species of snakes. Because of this bias in our current knowledge of the behavior of snakes my dissertation is focused on the chemosensory and behavioral ecology of three species of small-bodied and cryptic snakes, the Sharp-tailed Snake (Contia tenuis ), Ring-necked Snake (Diadophis punctatus), and the Desert Nightsnake (Hypsiglena chlorophaea).My dissertation had three main objectives: (1) To examine the effects of shelter-site and prey odor availability on behavior, (2) To test for prey chemical discrimination among these species, (3) to examine abitoic factors that influence activity patterns. Chapter 1 focused on the effects of shelter availability and prey odor on H. chlorophaea. Individual nightsnakes made nocturnal movements and chose shelters in combination with lizard odor, and avoided mouse odor. Chapter 2 described the effects of three moonlight intensities: (1) a new moon, (2) half-moon, and (3) a full moon on the activity patterns of H. chlorophaea. These data show a full moon to have a statistically significant effect on the movement patterns of H. chlorophaea. In Chapter 3, I show that H. chlorophaea is able to discriminate between two size classes of potential prey. Individuals has a lower latency (time to first tongue flick) and showed a greater mean rate of tongue flick towards a small sized (and ingestible) prey item over a larger, un-ingestible prey item. Chapter 4 shows that H. chlorophaea of two size classes (adults and juveniles) do not prefer invertebrate prey, an often repeated statement in both peer-reviewed papers and regional field guides. In Chapter 5, I show that Contia tenuis shows a preference for slugs as prey, reaffirming previous, yet unsubstantiated claims by several authors. Chapter 6, shows that shelter and prey odor has an effect on behavior, in the case on a diurnal species, Diadophis punctatus. Similar to H. chlorophaea , individual D. punctatus chose shelters in proximity to a suitable prey odor, in this case a snake, and avoided mouse odors.