Effect of Light Wavelength — Rosen et al. 



97 



I1a. Distilled Water (0 mOsm) 



1 1d. Artificial Snail Water + Mannitol (180 mOsm) 



5 6 7 8 

 Time (Hours) 



iilii 



5 6 7 8 

 Time (Hours) 



9 10 11 12 



140 



? 



£ 120 



£ 60 

 (0 



+ 40 



1b. Artificial Pond Water (15 mOsm) 



T 



4 5 6 7 8 

 Time (Hours) 



9 10 11 12 



■ 1e. Artificial Snail Water + Mannitol (267 mOsm) 



^ 140 T 



E 



120 



(b 



0 100 H 



1 80 



UJ 



1 20 



5 6 7 8 



Time (Hours) 



10 11 12 



1c. Artificial Snail Water (102 mOsm) 



5 6 7 8 9 10 11 12 



Time (Hours) 



Figure 1. Mean + SE vertical swimming distances (mm) for Proterortietra macrostoma cercariae over 12 hr in: (la) 

 Distilled Water; 0 mOsm; (lb) Artificial Pond Water; 15 mOsm; (Ic) Artificial Snail Water; 102 mOsm; (Id) Artificial 

 Snail Water + Mannitol; 180 mOsm; (le) Artificial Snail Water + Mannitol; 267 mOsm. 



P. macrostoma cercaria can be modulated by 

 exposure to red light or collectively the short- 

 er wavelengths of the visible spectrum while 

 controlling for light intensity. Light wave- 



lengths are absorbed differentially with in- 

 creasing water depth, and longer light wave- 

 lengths like red are absorbed much more 

 rapidly in water than shorter wavelengths 



