Xenopus laevis: Larvae Ethogram

Amphibians are fascinating creatures due to the metamorphosis that changes the physiology of the larvae to the adult stage. While adult Xenopus laevis have been studied extensively, the behavior of the tadpoles has little information available. These creatures, originally from Africa but with multiple generations bred in the lab, were studied in petri-dishes that contained 10% Holtfrieter’s solution to mimic the pond environment. The tadpoles that were observed on February 1st, 2018 were eleven days old at stage 49(nf) as confirmed by Dr. Whittemore’s lab at Keene State College.

To begin to understand the behavior of these tadpoles, a single larvae was placed into its own petri-dish and observed. After compiling a set of behaviors another tadpole was added and new behaviors and interactions were recorded. A scan sample of the two and a continuous sample on the larger tadpole were conducted for five minutes each to determine how often tadpoles partake in each activity that was observed and described.

**It is important to note that these tadpoles had been used in a neurology course at Keene State College earlier the same day and this stimulation could have impacted the behavior for this observation**

“A tadpole looking back at you.” by H. Schofield (CC 4.0)

Ethogram of Xenopus laevis Tadpoles

Individual Observation: 

Breathing- the head of the tadpole appears to move up and down in a bobbing motion as the mouth opens and closes to force water into the mouth and over the gills to take in oxygen. Is visible when the tadpole remains in one place.

Resting- tadpole remains in one spot, may vibrate tail but does not move, is often seen breathing.

Swimming- tail vibrates, moves back and forth to propel the tadpole forward.

Dancing- as the tadpole swims, the body rocks from side to side, exposing the underside of the organism. Often the tadpole spins and flips itself over in a rolling motion.

Attempted Swimming- continues to move tail from side to side but does not move forward due to an obstruction such as the wall of the container.

Flipping- while swimming the underside turns upright momentarily but does not complete the roll, turn back to normal and continues to move forward throughout the motion.

Vertical Propelling- tadpole moves downward toward the ground and swims in a vertical rather than horizontal/forward movement.

Twisting- while swimming the body rocks and the tadpole swims on its side.

Tail wagging- tail is rapidly moving but the tadpole remains still.

Group Observation:

Mouth Touching- two tadpoles face each other and the front of the head/face touch.

Cuddling- tadpoles congregate and rest together.

Chasing- tadpoles swims after another tadpoles and they bump into one another which changes the direction of the tadpole that is being chased.

Colliding- two tadpoles swim into one another.

Observations

  • Head bobbing was an indication that the tadpole was opening its mouth to pull in water to breathe. There were on average 50 head bobs per 30 seconds in both light and dark environments.
  • In a five minute scan sample with scans at 30 second intervals for a total of ten intervals, the tadpole was resting for 8/10 of the scans, 1 scan saw it swimming, and 1 scan saw it tail wagging.
  • In a five minute continue sampling on the larger tadpole in the petri-dish found that this tadpole spent 49.87% of the five minutes breathing, 45% of the time wagging its tail, 3.44% of the time attempting to swim. and 1.69% of the time colliding into the other tadpole.

Questions

  1. Would there be more collisions if there had been more than 2 being observed?
  2. Would there be more vertical propelling if tadpoles were placed in a container with more depth?

Hypothesis

  1. Tadpoles collide more often when they are in more crowded containers.
  2. Tadpoles experience more vertical swimming when in a container with more depth.

Predictions

  1. If there ten tadpoles in a container together then there would be more collisions per 5 minutes than in a container of the same size that contained only five tadpoles.
  2. If ten tadpoles were placed in a 100 mL beaker then there would be more scans that saw vertical propelling per five minutes than if ten tadpoles were placed in a 50 mL beaker.

 

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