REQUIREMENTS OF INSECTS 



30. H. Katznelson, /. Bad., 1944, 48, 495. 



31. Z. J. Ordal and R. K. Busch, ibid., 1946, 51, 791. 



32. M. Landy, D. M. Dicken, M. M. Bicking and W. R. Mitchell, 



Proc. Soc. Exp. Biol. Med., 1942, 49, 441. 



33. C. H. Gray and E. L. Tatum, Proc. Nat. Acad. Sci., 1944= 30, 



404. 



34. H. Mcllwain, Nature, 1946, 158, 898. 



16. EFFECT OF BIOTIN ON PLANTS 



Biotin and aneurine were claimed by F. Kogl and A. J. Haagen- 

 Smit ^ to be phyto-hormones, since each increased the growth of pea 

 embryos grown in a synthetic medium ; the effect of the two com- 

 pounds together was greater than that of either alone. The amount 

 of biotin, like that of other members of the vitamin B complex, increased 

 during the germination of oats, wheat, barley and maize. ^ 



References to Section 16 



1. F. Kogl and A. J. Haagen-Smit, Z. physiol. Chem., 1936, 243, 209. 



2. P. R. Burkholder, Science, 1943, 97, 562. 



17. BIOTEV REQUIREMENTS OF INSECTS 



Biotin is essential for the optimal growth of Triholium confusum ^' ^ 

 and of Sitodrepa panicea, Lasioderma serricorne and Ptinus tedus, but 

 not of Silvanus surinamensis.^ The diaminocarboxylic acid derived 

 from biotin (page 407) could partially replace biotin for Triholium. 

 The sterilised larvae of Lasioderma showed less satisfactory growth 

 than normal larvae without biotin, so that biotin may be a more 

 important factor in the absence of symbionts * (see page 115). Biotin 

 was necessary for the growth of mosquito larvae (Aedes aegypti) to 

 the fourth instar.^ It could be replaced by small amounts of oleic 

 acid or lecithin. 



Pollen and royal jelly are rich in biotin, as well as in pantothenic 

 acid (page 364), and it has been suggested that these two members of 

 the vitamin B complex may be concerned with the development of 

 bee larvae into queen bees.^ 



The addition of raw egg white to the diet of the larvae of the rice- 

 moth [CoYcyra cephalonica) inhibited growth, and caused death in 

 twenty -eight days. Avidin produced the same effect. When larvae 

 fed on egg white for fourteen days were given a diet rich in biotin, 

 growth was resumed and the increase in weight was approximately 

 proportional to the amount of biotin added.' 



441 



