It was already known that green algae lived inside the eggs of this species – the spotted salamander (Ambystoma maculatum), which is very common in North America.
Although these salamanders only emerge from beneath the ground to hunt and breed, they lay their translucent eggs in ponds, where they are suspended near the surface. This makes an ideal, sunny and protected environment for the algae.
“The eggs actually look green because the algae is inside the egg capsules,” explained Dr Ryan Kerney of Dalhousie University, who led the research.
“The algae inside the egg capsules provide oxygen to the embryo and the algae gets waste from the embryo [which is rich in the nitrogen the plant needs].”
Although this relationship had been known about for more than a century, scientists did not understand how the algae got into the egg.
from BBC – Earth News – Plant lives inside animal: algae invade amphibian cells
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