Date of Award

2-1-1969

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

Abstract

Food, growth, distribution, migration, metamorphosis, neoteny, and breeding habits of Ambystoma tigrinum diaboli Dunn were studied in Devils Lake, North Dakota. Salamanders I vere captured in gill and frame nets, and growth and metamorphosis were followed on specimens caged in the lake, lood habits were ascertained from stomach analyses and migrating adults were caught in gill nets and trench-barrier t raps.

Salamander adults breed readily in Devils Lake and display a sex ratio of 13 females to 10 males. The population appears to consist of larvae, neotenous gilled forms, aid adults. Adults leave the lake in fall and return in spring; larvae are present from time of egg hatching until late summer when they change to adults or "neotenies"t neotenous forms are apparently present at all seasons unless eradicated by winter kill. Breeding by neotenous forms was neither verified nor refuted; females had eggs in the body cavity in the fall of 1967 and had lost them before ice'melt in 1968. Major growth occurs during the first summer after hatching, but neotenies continued growth at a much slower rate during the second summer. Both larvae and neotenios metamorphosed into adults. Metamorphosis of neotenies could be induced by penning them in the lake or removing them to tanks and aquaria. Amphipods were the major food item of all 3 categories. Gastric and intestinal nematodes and cestodes were the only parasites found.

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