|Southern leopard frog eggs- note individual coating|
We are new to amphibian eggs this year and sought the guidance from our more knowledgeable friends.* If you too are new to this, here are some of the lessons learned. The first one is to differentiate between frog and salamander eggs. Frog eggs have a coating of jelly around each individual egg which can be seen in the picture below. A mass of frog eggs may contain 500-2000 eggs.
|Leopard frog egg mass in water- compare to maple leaf|
|American toad eggs|
|Leopard frog eggs- some showing early tails|
|Spotted salamander eggs in water.|
|Spotted salamander eggs- note all the eggs in one jelly coating|
Imagine being an egg in the middle of the mass, far away from the edges where the dissolved oxygen in the water exists. Spotted salamanders have an interesting and unique symbiotic relationship with a single celled green alga, Oophila amblystomatis. The algae takes up carbon dioxide and nitrogen waste products from the eggs and photosynthesizes oxygen. The eggs acquire the needed oxygen, continuing to develop into larvae while producing more carbon dioxide and the cycle continues. The New Scientist article calls this The First Solar-powered Vertebrate. The relationship has been known before but now there is proof that the algal cells exist inside the cells of the salamanders themselves. The algae is thought to be contained in the salamander germ cells and thus transmitted to each new generation.
MDC has a spotted salamander video but don't expect a lot of action as this one was rather bored with the whole process. Perhaps it had already bred and now was just waiting for next year, knowing that spotted salamanders have been known to live up to 32 years. A lot more pictures and information is available at fcps.edu/islandcreekes. **
* Thanks to Rhonda Rimer (MDC) for identifying the eggs and Jeff Brigler (MDC State Herpetologist) for confirming the ID. Also thanks to Brian Edmonds for the information on the green algae association.
** fcps.edu/islandcreekes/ecology/organism_menu is one of my favorite resources on ecology. In addition to great photographs of many species of plants and animals, it has a comprehensive listing of Relationships in Nature, listing prey, predators, shelter and other ecological associations. You will find its links scattered throughout the Resources link on the right.