The quantitative composition of major sugars in the nectars of 35 plant species was compared with that of 12 fruit juices. The use of specific quantitative assays for glucose, fructose, and sucrose made it possible to analyze large samples without quantitative chromatographic separations. Sucrose ranged from 0–99%. In most nectars, glucose and fructose were present in approximately equal amounts. No evidence was found for the presence of maltose, raffinose, and other oligosaccharides.
Ethological investigations of the salt-marsh mosquito, Aedes taeniorhynchus (Wiedemann), have disclosed a rather special importance to the time of day of emergence. Interest has therefore focused on the happenings around this critical time in the insect's life. In order to understand emergence and the behaviour of the mosquitos immediately after emergence-including such important habits as mating and migrating-it was found necessary to have further information on some aspects of the development of the aquatic stages.Field observations and rearing experiments were undertaken for this purpose at intervals between October 1951 and January 1953. It was hoped that a few experiments would be sufficient, but the problem was soon found to be considerably more complicated than expected, and the experiments reported here are only preliminary. From them, however, a few rather puzzling facts have been obtained, and an understanding of them may only be obtained by further experiments. Excellent conditions for such experiments will be provided in the proposed Entomological Kesearch Centre of the Florida State Board of Health. The interruption occasioned by the establishing of this centre can be advantageously used in summarising the knowledge so far obtained.
Experimental Technique.Since the technique varied from one experiment to the next, with some experiments being made in order to find the most suitable method, a short description of each experiment will follow.
Experiment 1.About 30,000 fourth-instar larvae and a few pupae were transported in 60 half-pint ice cream cardboard cartons from the Big Pond in Fort Pierce the 75 miles to Archbold Biological Station, Lake Placid on 7 October 1951. They were placed in a room in which temperature and light could be regulated, the temperature at 28° to 30°C* daytime and 19° to 22° night-time; " Sunrise " was simulated at 0730-0800 hr., and " Sunset " at 1945-2015 hr. As this experiment was made in order to get information on the behaviour of imagines of known age, only a few data on the larval development were recorded.
Experiment 2.Larvae were obtained from a mangrove swamp on Sanibel Island (off the south-west coast of Florida), 20 November 1951. Emergence had been in progress several days. Most of the collection was of fourth-instar larvae, but there were also a few third-instar larvae and pupae. The natural water in the mangrove pools was rather dark and had a specific gravity of 1-005 at 22°.The samples were taken to the laboratory at Lake Placid as fast as possible but many larvae died during transport. The remaining, healthy-looking larvae (all fourth-instar) were transferred to ice-cream cartons, 100 larvae to each. The surface area of a carton is 55 sq. cm., and the volume of water was kept at * All temperatures in this paper are given in degrees Centigrade.
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