The activities of enzymes associated with anaerobic pathways, glycolysis and the Krebs cycle in spiders.

1. The activities of eight enzymes that participate in or are closely linked to anaerobic glycolysis or the krebs cycle were measured in 11 species of spiders representing diverse taxonomic groups (Table 1). 2. The results indicate three anaerobic pathways may operate in spiders. The major pathway leads to the accumulation of D-lactate and one of the minor pathways to alanine and malate as postulated by Linzen & Gallowitz (1975). Another minor pathway ends with the accumulation of glycerol-3-phosphate and pyruvate (Fig 1). 3. There were no consistent correlations between the degree of development of certain pathways or enzyme activities and a spider's habits and respiratory exchange system. 4. Lactate pathways are much more highly developed in the legs and cephalothorax than in the abdomen.