Discussion 



Dr. Davenport: To the interesting discussions presented by Dr. Nicol 

 and by Dr. Buck I should Hke to add a few remarks in regard to an 

 aspect of bioluminescence beyond that of the physiological mechan- 

 isms of control. 



Greatest emphasis has been placed during the conference on the 

 biochemistry of luminescence, for the obvious reason that the 

 phenomenon has paramount importance as a tool of the investigator 

 of the basic metabolism of cells. Some emphasis has been placed on 

 mechanisms of control of luminescence, which in multicellular or- 

 ganisms must of necessity be investigated over the years in each 

 differing luminous species. Some emphasis, largely descriptive but of 

 great interest, has been placed on the natural history of luminous 

 organisms. But the subject of the experimental analysis of behavior 

 in luminescent organisms has barely been touched upon. 



It is obvious that a careful analysis of the behavior of luminous 

 forms should give us considerable information concerning the im- 

 portance of luminescence in their evolution. Although the question of 

 the adaptive significance of luminescence in particular continuously 

 arises, practically no investigations resembling the interesting ones of 

 Dr. Buck on Lampyrids have been undertaken. 



As an example of a case of luminescence which has been used, 

 without comparative studies, to bolster important evolutionary theory 

 we have that of the fungivoroid Diptera. Goldschmidt has used the 

 New Zealand species to support the theory that by necessity there 

 must have been sudden great evolutionary changes in morphology, 

 physiology, and behavior for the New Zealand form to have been 

 brought to its present level. It now appears as a result of Dr. Haneda's 

 observations that there are luminous members of this single dipterous 

 family as far separated as New Zealand, North Carolina, and Japan. 

 Such discontinuous distribution in closely related luminous forms 

 indicates that the habit of luminescence in these Diptera, although it 

 is not the same in each species, may be of as great geological antiq- 

 uity as that of the Lampyrids. 



Unquestionably, studies in comparative behavior in related lu- 

 minous forms should give us a clearer picture of their course of 

 evolution; let us hope that in the future more investigations will be 

 devoted to this interesting facet of the whole subject of biolumines- 

 cence. 



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