STORAGE OF CAROTENOIDS AND OF VITAMINS A 493 



variant of the mantis could not synthesize carotenoids, as it did not contain 

 them under any circumstances. It is uncertain whether the German cock- 

 roach or croton bug (Blatella germanica) , which can be raised on a diet com- 

 pletely devoid of carotenoids or of vitamin A,^^'^^^ does not require these 

 substances because it is able to synthesize them, or because it can carry 

 out its metabolic processes M'ithout vitamin A. Bowers and McCay^°- 

 were unable to demonstrate the presence of any preformed vitamin A in an 

 extract obtained from a large number of cockroaches. 



Goodwin^°2 estimated the proportion of carotene in the African and desert 

 locusts as 10 to 15 Mg-/g- of fresh weight. This is a considerably lower 

 figure than that (2.5% of dry weight) quoted by Brodskis and Rungs^"^-^"^ 

 for the desert locust (Schistocerca gregaria Forsk.). Although it has been 

 reported that preformed vitamin A occurs in locusts,^"^'^"* this claim could 

 not be verified by Goodwin and Srisukh^*"' either in the case of Locusta or of 

 Schistocerca. Goodwin ^^^.sss jg Qf ^j^g opinion that vitamin A is probably 

 absent in these insects, first because it has not been found in other insects 

 examined, and secondly because some species have been shown to exist on 

 diets completely devoid of carotenoids and vitamin A. However, this 

 last argument loses some weight in view of the recent demonstration of pre- 

 formed vitamin A in the case of some crustaceans, such as the North Sea 

 prawn {Palaemon serratus) ,^^^ and the Euphausiacean shrimps {Meganycti- 

 'phanes norvegica and Thysanoessa raachii).^^^ 



Many interesting variations in carotenoids occur in this group under 

 certain conditions. Thus, although the amount of astaxanthin exceeds 

 that of /S-carotene in the locust throughout the first several stages of de- 

 velopment, it begins to decline after the third stage, and /3-carotene becomes 

 the principal carotenoid.^"- On the other hand, the concentration of 

 /8-carotene, which is high in the eggs, decreases during incubation, concomi- 

 tantly with an increase in the astaxanthin content.^''^ It is also known that, 

 when locusts swarm, i.e., change from the solitary to the gregarious phase, 

 they undergo marked color changes. The green pigmentation character- 

 istic of the solitary phase is replaced by a much darker coloration, due to 

 melanin. ^°^'^°^ The green pigment in the locusts during the solitary phase 

 has been shown by Junge^^^ to be insectoverdin; this consists of a yellow 

 component (made up of a carotenoprotein complex containing both /3- 



601 R. E. Bowers and C. M. McCay, Science, 92, 291 (1940). 



502 T. W. Goodwin, Biochem. J., 45, 472-479 (1950). 



i^os B. Brodskis and C. Rungs, Bull. soc. sci. nat. Maroc, 24, 7-9 (1944). 



50^ B. Brodskis, Bull. soc. sci. nat. Maroc, 24, 9-10 (1944). 



505 T. W. Goodwin, Biochem. J., 47, 554-562 (1950). 



506 T. W. Goodwin, Biol. Revs., 27, 439-460 (1952). 



