Cold Hardening in the Neotropical Tungara Frog (Engystomops pustulosus)

Poster Number

25

Lead Author Major

Biological Sciences

Format

Poster Presentation

Faculty Mentor Name

Marcos Gridi-Papp

Faculty Mentor Department

Biological Sciences

Abstract/Artist Statement

Frogs are ectotherms, and exhibit physiological mechanisms that increase temperature tolerance and survival upon repeated exposures to cold temperatures. If the change takes place in a short period of time, it involves quick biochemical modifications in the cell and is called hardening, whereas slower adjustments that occur over weeks are called acclimation. Frogs from temperate regions are known to both harden and acclimate, whereas tropical frogs fail to acclimate and have not been tested for cold hardening. I have tested cold temperature hardening in seven tungara tadpoles from different broods. The tadpoles were placed in a Petri dish with 60 ml of water. The temperature of the water was decreased until the tadpole stopped beating its tail in response to gentle probing of its tail. The water was then returned to its original temperature over a period of one hour. After that, the temperature was decreased a second time until the animal stopped responding again. I found that the average no-response temperature was 8.6 C and it was 1.04 C lower in the second exposure than in the first one. This difference is statistically significant (P = 0.018) and confirms that the neotropical tungara frog can harden when exposed to cold. The current belief that tropical frogs have lost the ability to acclimate due to the lack of need, therefore, cannot be generalized to hardening or it does not apply to all frogs.

Location

DeRosa University Center, Ballroom

Start Date

26-4-2014 2:00 PM

End Date

26-4-2014 4:00 PM

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Apr 26th, 2:00 PM Apr 26th, 4:00 PM

Cold Hardening in the Neotropical Tungara Frog (Engystomops pustulosus)

DeRosa University Center, Ballroom

Frogs are ectotherms, and exhibit physiological mechanisms that increase temperature tolerance and survival upon repeated exposures to cold temperatures. If the change takes place in a short period of time, it involves quick biochemical modifications in the cell and is called hardening, whereas slower adjustments that occur over weeks are called acclimation. Frogs from temperate regions are known to both harden and acclimate, whereas tropical frogs fail to acclimate and have not been tested for cold hardening. I have tested cold temperature hardening in seven tungara tadpoles from different broods. The tadpoles were placed in a Petri dish with 60 ml of water. The temperature of the water was decreased until the tadpole stopped beating its tail in response to gentle probing of its tail. The water was then returned to its original temperature over a period of one hour. After that, the temperature was decreased a second time until the animal stopped responding again. I found that the average no-response temperature was 8.6 C and it was 1.04 C lower in the second exposure than in the first one. This difference is statistically significant (P = 0.018) and confirms that the neotropical tungara frog can harden when exposed to cold. The current belief that tropical frogs have lost the ability to acclimate due to the lack of need, therefore, cannot be generalized to hardening or it does not apply to all frogs.