Spring egg mass counts are also complete out at Heiberg, and even though the wood frogs and spotted salamanders had a late start this year because of the late thaw, they are prolific as ever! The little egg masses still have a long road ahead of them, and must survive voracious predators like predaceous diving beetles and green frog tadpoles. Huh? Yep - green frogs deposit their eggs here in the Northeast US in the summer, and once they hatch, the tadpoles bury themselves in the muck and keep growing throughout the winter (sometimes they will even delay metamorphosis for 3 years!). That means by the following spring they are big enough to make a tasty morsel out of little wood frog eggs. Please enjoy the following videos of a Dytiscid beetle and some yearling green frogs munching away, as goes the circle of life. Feel free to imagine a Sir David Attenborough narration, accompanied by the chorus of peeps and trillings of spring peepers in the background.
Now for a salamander breeding rundown: Spotted salamanders (like other members of the order) reproduce via spermatophores - little gelatinous "sperm packets" attached to a sticky base. Males will deposit these spermatophores on substrate, leaves, rocks, or sticks, and females will come along and take the sperm up into her cloaca (multipurpose genital and excretory opening). Thus salamander eggs are fertilized internally before they are deposited, unlike the externally fertilized frog eggs. If you take a close look at the photo below, you can see little white blobs on the leaf litter covering the pool bottom. These are spermatophores that were rejected by females and not used for fertilization. Better luck next time, guys!!
No comments:
Post a Comment