Populations (n = 25) of fourth instar Aedes aegypti were introduced into observation arenas that contained one of 5 types of substrates, and were sub-divided into 5 equal 1 cm horizontal zones. The larvae were videotaped to determine effects of food quality, food quantity, and nutrient deprivation on vertical distribution of larvae over time. At least two-thirds of the larvae consistently aggregated at the surface and on the bottom. The proportion depended on the nature of the substratum and was influenced by nutrient deprivation. In contrast, density of larvae in the 3 remaining zones was consistently low and was unaffected by either of these variables. Larvae were typically very active during a 15 minute period of acclimation upon introduction into the observation arena; subsequently, levels of activity declined. Most starved larvae in the presence of a high-quality food substrate fed to repletion faster than fed larvae, whereas in an arena devoid of food, they foraged on the bottom for a longer duration of time than the fed. With a substrate of a semi- or highly non-nutritive nature, foraging again appeared more intense among starved than fed individuals. Starved larvae consistently aggregated on the bottom, in contrast to fed individuals that became more evenly distributed between the surface and the bottom.

<p>The major aim of this study is to determine and compare the distribution of bacteria and actinobacteria in Marion Island terrestrial habitats.</p>

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