conditi Introduction Do age class 0 snakes delay feeding in the wild? Do age class 0 snakes delay feeding in the wild? To Eat or Not to Eat? Feeding and Growth Strategies in Neonatal Lake Erie Watersnake, Nerodia sipedon insularum Elizabeth W. Mack 1, Jennifer L. Beck 2, Kristin M. Stanford 2, Richard B. King 1 1 Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois USA 2 F.T. Stone Laboratory, The Ohio State University, Put-In-Bay, Ohio USA Faster growing neonatal snakes are more successful than their smaller litter mates (Jayne & Bennet, 1990; Kissner & Weatherhead, 2005), and early growth can also increase adult size and fitness (Madsen & Shine, 2000). Unlike related species, Lake Erie Watersnakes do not appear to feed or grow before their first hibernation and delay maturity until their third or fourth (Rossman et al., 1996; King, 1986; Stanford, 2012). Knowing that larger, faster growing neonates are more likely to thrive than their smaller littermates, I asked three research questions: Results of field prey study for age class 0 and age class 1 snakes. Observations were grouped by week, and the age in growth days is calculated for the first day of the week. Responses of snakes during feeding trials as a function of their age in growth days. Circles are scaled to represent the proportion of snakes exhibiting each response during a feeding trial period. The sigmoidal curve estimates the proportion of snakes expected to eat based on their age in growth days. The Lake Erie Watersnake, Nerodia sipedon insularum, is a New World natricine endemic to the islands of western Lake Erie. This snake was listed as threatened in 1999 and was removed in 2011 due to recovery (U.S. Fish and Wildlife Service, 2011). Neonates are born in late August-early September and enter hibernation in mid October. Between birth and hibernation, snakes are classified as age class 0. They are classified as age class 1 when they exit hibernation in the spring. Study Species: The Lake Erie Watersnake Relative masses of yolk/carcass, fat bodies/carcass, and combined yolk and fat bodies/carcass for neonates from five natricine species. Dissected Gartersnakes and Brown Snakes did not contain any fat reserves. Relative masses for Graham’s Crayfish Eating Snake and Queen Snake were estimated from Figure 5 in Waters and Burghardt (2005). Boxes indicate homogeneous subsets for Combined:Carcass ratio. I collected snakes of both age classes from field sites on five islands. For each snake, I took standard measurements and recovered any prey items through voluntary regurgitation or palpation. Proportions of snakes containing prey were calculated for each sample date and compared. Is delayed feeding the result of a lack of feeding opportunities? Is delayed feeding the result of a lack of feeding opportunities? I performed laboratory feeding trials with both age classes at the F. T. Stone Laboratory. Snakes were individually housed and offered live shiners overnight. A binary logistic regression analysis was used to compare age classes and determine when young Lake Erie Watersnakes begin feeding. CV How do snakes survive their first fall and winter without eating? How do snakes survive their first fall and winter without eating? Neonatal snakes store energy in the form of fat bodies and an internal yolk sac. I removed yolks and fat bodies from stillborn newborns of five natricine species and dried them for five days. A Kruskal-Wallace test and post-hoc multiple comparisons allowed me to compare species and determine homogeneous subsets. Yolk Fat bodies Conclusions Age class 0 snakes do not feed in the fall in the wild. Delayed feeding still occurs with ideal thermal conditions and available prey. Conclusion: High levels of fat reserves facilitate delayed feeding in Lake Erie Watersnakes. The authors wish to thank NIU, the Ohio State University’s F. T. Stone Laboratory, and Ohio Sea Grant for funding and logistical support. Special thanks to Blair Perry, Matt Thomas, and all of the field assistants at Stone Lab for their assistance in the field and during laboratory experiments. For their input on this poster and project, we thank Dr. Nick Barber, Dr. Bethia King, Eric Hileman, Emily Virgin, and Dr. Collin Jaeger. Photo credits: EWM, RBK, Blair Perry, Amanda Buckiewicz. References: Jayne, B. C. and A. F. Bennett Evolution, 44(5): ; King, R. B Copeia, 3: ; Kissner, K. J. and P. J. Weatherhead Journal of Animal Ecology, 74: ; Madsen, T. and R. Shine Journal of Animal Ecology, 69: ; Rossman, D. A., N. B. Ford, and R. A. Seigel University of Oklahoma Press, Norman, Oklahoma; Stanford, K. M PhD. Dissertation. Northern Illinois University, DeKalb, Illinois; USFWS Federal Register, 158: ; Waters, R. M. and G. M. Burghardt Animal Behavior, 69: Acknowledgements Age class 0Age class 1