1. The influence of larval growth history and exogenous thyroid hormone on life history allocation patterns in the axolotl (Ambystoma mexicanum) Pamela M. Clarkson and Christopher K. Beachy Minot State University

2. larval period metamorphic size Lab manipulations of growth almost never confirm this. This pattern is uncommonly observed in nature. Wilbur and Collins, 1973

3. energy intake larval period metamorphic size larval period metamorphic size larval growth metamorphic development storage sexual maturation

4. energy intake larval growth storage sexual maturation larval period metamorphic size larval period metamorphic size

5. energy intake larval growth storage sexual maturation energy intake larval growth metamorphic development storage sexual maturation Ambystoma mexicanum + 5 nM TH

6. TIMELINE in days hatching initiate food treatments first metamorph last metamorph initiate TH treatments switch food treatments first weighing second weighing third weighing fourth weighing 14 March 2007 21 January 2008 Metamorphic (and control) weights metamorphic timing (TH) gonad mass fat body mass metamorphic mass Two-factor MANOVA

7. control 5 nM TH

8. Big Gonads Big fat bodies

9. switched to low food switched to high food metamorphic mass (g) Metamorphs (TH treated animals)

10. switched to high food fat body mass (mg)

11. PAEDOMORPHSMETAMORPHS fat body mass (mg)

12. Our Results In the low-high group, metamorphosis was delayed similar to the Wilbur-Collins hypothesis

13. Final Analysis Suggests storage and metamorphic development interact  classic Wilbur-Collins model Storage rather than growth may be an indicator of environmental quality or deterioration

14. ACKNOWLEDGMENTS Heather Modrow (MSU) Leah Crites (MSU) Charles Crites (MSU) Sharon Denks (FBCC) Dwight Blackhawk (FBCC) Karen Pocha-Melby (MSU)