CHEMORECEPTION: LOCOMOTION AND ORIENTATION 



307 



> 



o 



o 



c 

 o 



O 



Quodront 2 



Quadrant i 



Quadrant 3 



Quadrant 4 



Site of Chemical Stimulation 



Figure 25 Data from Fig. 23: regressions of the percentage of distance 

 traveled in the four quadrants of the monitor, as a function of the position of 

 the needle releasing the chemical stimulation. From Kleerekoper et al. 

 (1975). 



delivery, and gradient characteristics of each individual site. The evidence 

 presented above shows that the distance between the release site and the wall 

 through which the tank exits is what determines the differences between the 

 two curves. The greater that distance, the greater the dispersion of the 

 stimulus and the shallower its gradient. 



In stagnant water, the statistical relationship between the positions of sites 

 1 and 6 and the percent of distance traveled in the quadrants has a reduced 

 linear slope. That is, it is less sensitive than that in flowing water and there is 



