Data were obtained on population and general biology of three non-reproductive overwintering colonies ofthe monarch butterfly, Danaus plexippus (Danaidae) during April-August in 1980,1981 and 1982 at a site near Camden in New South Wales. A mark, release and recapture study showed that the 1981 colony was largely stable and the 1982 colony was migratory. In 1980 and 1981 populations comprised less than 500 individuals but in 1982 a peak population of 3500 butterflies was recorded. Males were sexually active throughout clustering. Most females were mated but showed no ovarian development. Periods of flight and feeding activity were common. The condition of most butterflies did not deteriorate markedly during clustering. Comparisons between winter non-reproductive monarch populations in North America and Australia are discussed.
Distribution of the monarch butterfly, Danaus plexippus (L.) (Lepidoptera: Nymphalidae), in western North America
