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Procambarus alleni Coloration as Impacted by Diet and Environment Name: Introduction The blue morphed Procambarus alleni is one of the most common invertebrates for trade within the United States aquaculture. The reason for this morph is an autosomal recessive trait that can be attained in mass quantities through selective breeding. It has been observed that certain species of crayfish have been able to change their exterior coloration when subjected to different environments. This may be due to the crustaceans chromatophores, which are light sensitive cells on the crayfish carapace that are able to reflect the hues of the habitat that the crustacean is placed. A major pigment in the crayfish’s exterior is astaxanthin which is synthesized from carotene and reacts with proteins to produce colors. It is felt that part of the genetic enzyme defect that is passed on recessively causes the body to release uncontrolled levels of astaxathin, giving the Procambarus alleni its blue shade. This study will examine how environmental coloration and diet effects the crayfish pigmentation. Methods Twenty mature specimens of the blue morph Procambarus alleni will be obtained from a breeder and submitted to a three week stabilization period in which the invertebrates will undergo universal conditions to acclimate to their new surroundings before testing. Each specimen will then be weighed, measured, and an initial record of coloration will be documented at two locations on the body (thorax and posterior dorsal region of carapace), using common color platelets. Three control specimen will remain in the stable monochromatic environment being fed a standard pellet diet. Two crayfish will undergo no other changes than a high protein diet and a carotene restricted diet. The fifteen remaining specimens will each be placed in an environment solely consisting of a single color based on different chromatophores. Chromatophores 40x Yellow - Xanthophores Red - Erythrophores Black/Brown – Melanophores Blue – Cyanophores White – Leucophores All other aspects of habitat and behavior will be recorded including; molting processes, temperature, lighting, water quality, and general behavioral patterns. At the end and midpoint of a two month period repeated documentation of weight, size, and coloration, will take place at which point a conclusion will be generated and nonparametric statistics made. References Bauer, R. T. 1981. Color Patterns of the shrimps Heptacarpus pictus and H. Paludicola (Carida: Hippolytidai). Mar. Biol., 64:141-152. Black, J.B. 1975. Inheritance of the blue color mutation in the crawfish Procambarus acutus acutus (Girard). Proc. La. Acad. Sci., 38:25-27. Dowell, V. E. and L.P.Winier. 1969. A bilateral color anomaly in the crayfish, Orconestes immunis (Hagen). Proc. Iowa. Acad. Sci., 76:487-492. Dunham, D. W., S. D. Jordan and M. Niglas. 1979. A new color morph of the crayfish Orconectes propinquus (Girard). Am. Midl. Nat., 102:384-387 Hairston, N. G., Jr. 1979. The effect of temperature on carotenoid photoprotection in the copepod Diaptomus nevadensis. Comp. Biochem. Physiol. A, 62:445-448. Hand, C. 1954. A blue crayfish from California. Calif. Fish Game., 40:437-438 Hayes, W. A., II and R. D. Reimer. 1975. Blue color anomaly in an Oklahoma crayfish (Decapoda: Cambaridae). Proc. Okla. Acad. Sci., 55:51. Herbert, P.D.N. and C.J. Emery. 1990. The adaptive significance of cuticular pigmentation in Daphnia. Funct. Ecol., 4:703-710. Kent, W. J. 1901. The Colors of the crayfish. Am. Nat., 35:933-936. Loeb, H. A. 1967. A rare blue crayfish. Conservationist. Feb.-March 1967:16-17. Momont, W. T. and J. E. Gall. 1971. Some ecological notes on the blue color phase of the crayfish, Orconectes virilis, in two lakes. Ohio J. Sci., 7 1:63-370. Newcomb, C. L. 1929. A new blue crayfish. Science, 70:217. Penn, G. H. 1951. A color anomaly of the Louisiana red crayfish, Procambarus clarkii (Girard). Proc. La. Acad. Sci., 14:66-67. Portman, A. 1959. Animal camouflage. Univ. Mich. Press, Ann Arbor. 111 p. Roberts, T. w. 1944. Light, eyestalk chemical, and certain other factors as regulators of community activity for the crayfish, Cambarus virilis (Hagen). col. Monogr., 14:360-389. Smiley, J. W. and W. W. Miller. 1971. The occurrence of blue specimens of the crayfish Procambarus acutus acutus (Girard) (Decapoda, Astacidae). Crustaceana, 20:221. Procambarus Alleni Cherax sp. Blue Moon Cherax Preissii Protein Synthesis Predicted Results The specimens from Set A that are kept in the different colored environments will begin to display colorations similar to their background. More importantly the specimen kept in the blue habitat will have an increase in the vibrancy of its already blue shade. The specimen from Set B that is on a carotene restricted died will display the most drastic color improvement. Followed by the specimen on the high protein diet, and lastly the control specimen will show the least change in coloration. Conclusions The Procambarus alleni is able to adapt to their environment and change their coloration in response to their background. This is a survival technique in order to camouflage themselves for protection against predators. In the aqua culture it would be best to suggest that aquarists use a blue substrate/gravel mix with their invertebrates and a carotene restricted diet in order to achieve ultimate vibrancy in this species blue hue.