DEVELOPMENTAL ARREST IN LEPTODACTYLUS-FUSCUS TADPOLES (ANURA, LEPTODACTYLIDAE) .2. DOES A FOAM-BORNE FACTOR BLOCK DEVELOPMENT

Several experiments were performed to test the hypothesis that foam ma de by hatched Leptodactylus fuscus tadpoles contains an inhibitor that maintains them in a state of developmental arrest. The results did no t support the hypothesis. Tadpole-made foam did not inhibit the develo pment of earlier stage L. fuscus, later stage L. fuscus or tadpoles of another species, Colostethus trinitatis, nor did removal from foam in itself release tadpoles from developmental arrest. Developmental arre st was found not to be obligate: tadpoles transferred to water at prea rrest stages developed continuously through to later stages. Prelimina ry evidence suggested that transfer to water alone, irrespective of th e presence of food, allowed tadpoles to bypass the arrest stage at lea st partially, possibly using their yolk reserves to continue developme nt. The possibility that developmental arrest is mediated via Candida or Prototheca infection is briefly discussed.