So, the old water theory, huh? I have heard that one for years. The way the VFT closes has been shown by one group to be instantaneous cell growth. When the trigger hairs are stimulated twice (you got that part right) the outer cells have been shown to grow instantly by 25%. The inside cells do not expand so this sudden growth forces the traps jaws to "grow together" in 1/25th of a second. In essence, it warps the trap shut. When it is finished digesting prey, the opposite happens. The outside cells do not grow, but the inside ones now expand, at a much slower rate. Again, it warps open. Touching the triggers once sends an electrical impulse causing the cell to set itself, waiting for the second impulse. The "set" causes the cell to expand 5 to 10%. Instant cell growth. That is how the VFT closes.
Having heard these two ideas kicked around for years makes me realize one thing. AIN'T NOBODY SURE OF WHAT REALLY MAKES THE PLANT CLOSE!!!!!!!! However, I love the theories and say either one could be right, or wrong. I favor the instant cell growth idea. Makes sense to me.
If you want super duper size VFT's, and all it takes is heat, then put your plants and tray on a heat mat, set it for 85 degrees, and see what shakes. Pretty old stuff I am hearing here. Nothing new. So, what makes a VFT red? And how do they get red? What are the triggers that cause it?