Abstract

The spotted salamander, Ambystoma maculatum, exhibits two color morphs of egg mass, white and clear. Factors that contribute to the maintenance of this dimorphism have been explored, but no consensus has been reached. White egg masses are preyed upon less than clear egg masses, suggesting an advantage to white masses. Previous work has shown that larvae from clear egg masses have greater mass than those from white; however, the mechanisms and consequences of this are unknown. A. maculatum embryos of both color morphs have a mutualistic relationship with a green alga, Oophila amblystomatis, that grows in the egg capsules. The mutualism may benefit clear egg masses, as the translucent jelly may allow for greater algal density than in the white egg masses. I asked whether larvae from clear and white masses differ in survivorship or performance and, if so, whether this difference is mediated by differences in algal density. I paired clear and white masses in a pond during the embryonic period and then determined egg capsule algal densities. Larvae from these eggs were subject to swim trials and were subsequently measured. I also conducted a mesocosm predation study to determine if there were differences in larval survival between color morphs. There was no significant difference in egg membrane algal density between clear and white masses. Subsequently, there were no differences in larval performance trials and morphometric measurements between morph types or any significant differences in larval survival between morphs.

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