Reference: Biol. Bull.. 137: 155-160. (August, 1969) PURINE EXCRETION IN FIVE SCORPIONS, A UROPYGID AND A CENTIPEDE FRANCIS R. HORNE Department of Biology, Southwest Texas State College, San Marcos. Texas 78666 Terrestrial arthropods differ in patterns of nitrogen excretion. Although insects generally are uricotelic, hypoxanthine and possibly xanthine have been identified in the moth, Galleria mellonella (Nation and Patton, 1961). Excreta of G. nicl-lonella contained 2.6% uric acid and 0.2% hypoxanthine. In contrast to insects, the principal nitrogenous waste of arachnids appears to be guanine. Only guanine was detected in the excreta of 34 species of spiders (Anderson, 1966). Anderson's work, in conjunction with the reports of earlier workers (Vajropala, 1935 ; Schmidt, Liss and Thannhauser, 1955 ; Atkinson and Chorlton, 1956; Haggag and Fouad, 1965), clearly illustrates the importance of guanine as the excretory product of spiders. Scorpions, however, are more incon-sistent than spiders in their pattern of nitrogen excretion. Gregoire, Gregoire and Miranda (1955) reported high concentrations of guanine in the excreta of speci-mens of Androctonus aitstralis and A. amoreit.i'i, but failed to detect either adenine or hypoxanthine. In India, Kanungo, Bohidar and Patnaik (1962) reported adenine, hypoxanthine. and uric acid, but not guanine or xanthine in excreta of Palamnaeus bengalensis. An extensive study by Rao and Gopalakrishnareddy (1962) showed that guanine was the most abundant purine excreted by the scorpions, Hetcrometrus fulvipes, Lvcas tricar mains, Biitluis tain it! its. and the uropygid, Thelyphonus sepiaris. Uric acid and hypoxanthine were of lesser im-portance. From these accounts scorpions seemingly differ both qualitatively and quantitatively in the purines excreted. Because arachnids consume considerable amounts of uric acid from their insect prey, the role of diet as an influential factor affecting purine excretion in scorpions and uropygids has been investigated. An evaluation of the malpighian tubules in purine excretion in a centipede (Chilopoda) and a scorpion also is presented. METHODS Excreta of the following arthropods was analyzed. Class Arachnida : Order Scorpiones : Buthidae C entrur aides mar ginaritalus Buthidae Centruroides vittatus Scorpionidae Heterometrus sp. Vejovidae Vejovis sp. Vejovidae I'ejoi'is mexicantts Order Urogpygi : Mastigoproctus giganteus 155
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