Prey Chemical Discrimination by the Desert Nightsnake (Hypsiglena chlorophaea): A Comparison of Invertebrate and Vertebrate Prey

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Biological Sciences

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We investigated responses of adult and juvenile Desert Nightsnakes (Hypsiglena chlorophaea) to odor extracts of potential invertebrate and vertebrate prey. Snakes were collected during 2009 from three localities in Washington state. We obtained odor from three potential invertebrate prey—spider (Tegenaria spp.), scorpion (Paruroctonus boreus), and field cricket (Gryllus spp.)—and compared responses with a vertebrate prey item, a Western Terrestrial Gartersnake (Thamnophis elegans). All potential prey items were collected at the same site as H. chlorophaea. We presented odors on 15-cm cotton swabs held 2.5 cm in front of the snake's snout. For each trial we recorded the number of tongue flicks in 60 sec, the latency to first tongue flick, and whether the stimulus elicited an attack. We observed no significant difference in latency of responses between spider, scorpion, cricket, or snake odors. However, both adult and juvenile H. chlorophaea responded with higher tongue-flick rates to snake odor. Juveniles showed an increase in tongue-flick rate toward crickets. Attacks were made against snake odor with no difference between adult and juvenile responses. Our results indicate that adults and juveniles of H. chlorophaea do not feed on invertebrates, and in some cases invertebrates may pose a threat to small snakes such as H. chlorophaea. However, the diet of H. chlorophaea may vary geographically, and populations of H. chlorophaea with a more southerly distribution may feed on invertebrates. Whether such differences in diet exist between populations will remain unresolved until additional studies of the diet of southern populations of H. chlorophaea are compared with those of northern populations.


This article was originally published in Journal of Herpetology. The full-text article from the publisher can be found here.

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Journal of Herpetology


© 2012 Society for the Study of Amphibians and Reptiles