Meeting Abstract
The silver spoon hypothesis predicts that favorable conditions early in life continue to provide an advantage through adulthood, even if conditions worsen. Although a variety of taxa exhibit this effect, few studies have involved amphibians. We tested the silver spoon hypothesis in the American Toad, Anaxyrus americanus, by rearing larvae in the lab in low density, high resource tanks (n = 14) and high density, low resource tanks (n = 14). Once larvae reached a standard size of approximately 2.3 cm and 0.2 g, we selected three size-matched larvae from each tank and transferred them to a second tank containing either a high food level (ad libitum, n = 7) or a low food level comparable to that experienced in the initial high density tanks (n = 7). We measured change in mass after one week and then toadlet snout-vent length and mass once metamorphosis was complete. Before transfer, larvae in low density tanks grew significantly faster than those in high density tanks and reached the standard size three days sooner. As expected, those larvae transferred to the high food level grew significantly faster than those transferred to the low food level. However, within both food levels, larvae initially reared at the low density grew faster than those reared at the high density, despite having identical food resources post-transfer. Larvae initially reared at low density also metamorphosed into significantly larger toadlets. This supports a silver spoon effect in that larvae reared under favorable conditions early in development acquired a growth advantage that persisted through metamorphosis. Future studies should consider lasting effects later in life.
