Meeting Abstract
The common mudpuppy (Necturus maculosus) was once common in temperature lakes of North America, however, very little is known of their current population status or basic natural history, including seasonal movements. Intriguingly, these ectotherms appear to exhibit inverse seasonal activity patterns, increasing activity during the winter months. The physiological and ecological factors determining these patterns are poorly understood. While metabolic adaptations likely play a role, we suspect reproductive and foraging ecology are also central determinants of these seasonal activity patterns. In collaboration with the Shedd Aquarium veterinary staff, we implanted radio-telemetry transmitters in 27 mudpuppies between March and December 2017, at Wolf Lake in Chicago, IL. Mudpuppies were located every ~16 days from April 2017 – July 2018. Farthest movements were correlated with water temperature increases during March 2017 – December 2017, but not during December 2017 – July 2018. In addition to seasonal movements, we measured water-borne reproductive hormone metabolites and temperature dependent metabolism in captive animals. Increased encounters (captures and sightings) during colder temperatures may indicate mate searching or higher energy demands in preparation for ovulation and egg laying, as mudpuppies breed in late fall to early spring. Higher activity in the winter may be linked to increased catchability of fish or decreased seasonal predation. Temperature dependent metabolism suggests adaptations related to winter reproduction or foraging. Increasing our understanding of the mechanisms underlying seasonal movements and habitat selection of this distinctive salamander will facilitate conservation efforts in a changing climate.
