Evol Ecol Res 18: 637-650 (2017)     Full PDF if your library subscribes.

An advantage of clear over white egg mass morphs in metabolically demanding microhabitats suggests a role of symbiotic algae in the maintenance of a polymorphism in the spotted salamander (Ambystoma maculatum)

Rebecca E. Hale1, Caroline Kennedy1, Danielle Winkelman1 and Chelsea Brown2

1Biology Department, University of North Carolina Asheville, Asheville, North Carolina, USA and 2NC State Mountain Horticultural Crops Research and Extension Center, Mills River, North Carolina, USA

Correspondence: Rebecca E. Hale, Biology Department, University of North Carolina Asheville, Asheville, NC 28804, USA. email: rhale@unca.edu


Background: Many populations of the spotted salamander, Ambystoma maculatum, have clear and white egg mass morphs. It is unclear what drives the maintenance of this polymorphism. The egg mass jelly of both morphs limits oxygen diffusion from water to interior embryos. However, an endosymbiotic alga compensates by increasing oxygen levels through photosynthesis. Jelly in white egg mass morphs may reflect the light necessary for algal photosynthesis.

Question: Does the relative success of the two egg mass morphs vary with microhabitat differences in oxygen stress for embryos and, thereby, differences in need for supplemental oxygen from algal symbionts?

Hypothesis: Embryos in warm water with low dissolved oxygen may require oxygen supplementation from algal photosynthesis to successfully complete development. In such conditions, the white morph may be at a disadvantage relative to the clear morph.

Organism: A western North Carolina population of A. maculatum.

Methods: In the laboratory, we compared the development and hatching success of clear and white egg mass morphs under light (algae present) and dark (algae absent) conditions. We also placed egg masses under a range of temperatures and dissolved oxygen conditions in the field, then compared embryo development and survival of clear and white morphs.

Conclusions: When oxygen demand is high – such as in warm, shallow water – embryos from clear masses have higher survivorship than do those of white masses, supporting our hypothesis that the clear morph has a developmental advantage over the white morph that is mediated by the algae.

Keywords: Ambystoma maculatum, Oophila amblystomatis, life history, oxygen, symbiosis.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2017 Rebecca E. Hale. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.