Friday, May 1, 2015

Tadpole Feeding Frenzy

The Wood Frog tadpoles have been growing rapidly and have just about eliminated algae and soft plant material from the pond.  In a typical year, the waste produced by the tadpoles acts as a fertilizer to stimulate the growth of algae which the tadpoles then eat.  As the tadpoles grow, they produce a greater quantity of waste which makes even more algae grow.  The excess rainfall we have had during the past few weeks has diluted the concentration of nutrients in the pond and slowed the algae growth.

This is a typical Wood Frog tadpole dispersal pattern.  Each tadpole is engaged in a random search for food.  They nibble their way across the pond bottom, check every surface of submerged plant material, and even turn belly up to skim the film of pollen grains from the water’s surface. 

Occasionally, an especially appealing food source will cause a pile-up of tadpoles.

These tadpoles are all competing for some tasty morsel hidden from view by the mass of tadpole bodies.

This short video reveals the source of their excitement.  A chance to nibble on a drowned worm is the prize in this competition.  At this point the worm seems to have been broken into several sections.  One section of worm becomes visible when it is drug to the top of the heap and pulled out of the picture at the top of the frame.  As the tadpole runs off with the leading edge of the worm, three other tadpoles get pulled along for the ride.  The lead tadpole is only out of the picture for a second before it comes right back in and dives into the same confusion it had just escaped.  Its three followers are still trying hard to get some of the worm for themselves.  I’ve witnessed this same type of behavior directed towards a variety of partially decomposed small animals.  Tadpoles thrive on algae, but they love a bit of meat in their diet.  The video can also be seen on YouTube by clicking HERE.

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