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	ECOS Issue 20

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Insects help clear weed-infested waters
About 20 years ago the pretty blue flowers of water hyacinth first made their appearance in the Gingham Watercourse, one of the network of channels through which the Gwydir River flows just downstream of the New South Wales town of Moree. At that time nobody took the plant seriously, but by 1975 some 10 000 ha of wetlands had become clogged by water hyacinth, together with a bullrush known as cumbungi.
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DDT, thin egg-shells, and an Australian falcon Does contamination by the insecticide DDT cause the shells of some birds' eggs to become thinner? If so, has breakage of the weaker eggs in the nest caused populations of some birds of prey, in particular, to decline? Download Article

Watching out for winged pests from our north Australia, the island continent, is free from a number of damaging insect pests that worry farmers overseas. Is it possible to keep it that way? The long sea journey to Australia might have helped us keep a number of pests out in the early years, but today, fast ships and aircraft have removed this protection. Download Article

Will better batteries get the electric car moving?
Electric cars are hardly new. In 1904, they made up one-third of the cars in large American cities. In their heyday, about 1912, 20 000 electric cars roamed the land. The world land speed record of 106 km per hour was held in 1899 by a battery-powered car, and enthusiasm for the 'electric' was manifested by such later examples of electrical traction as tip trucks, taxis, buses, and, of all things, a semi-trailer.
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Water in the world’s driest continent The availability of water has shaped our country's history right from the beginning of European settlement. Botany Bay lacked potable water, so the settlers chose Port Jackson instead. Download Article

Your house as a passive solar collector Turning your house into a ‘passive’ solar collector is a matter of maximizing the amount of heat the house gains in winter and minimizing it in summer. In this way, comfort is improved without the need for ‘active’ solar collectors. Download Article

Pheromones — clean weapon against insects? Back in the 17th Century, European naturalists used to put virgin female moths into cages. These virgins would then attract males to their doom — which in this case was to finish up pinned out in the naturalists' moth collections. Download Article

Sea snakes in the prawn net Of all the different types of sea creatures harvested around Australia, prawns are the second-largest export earner — and most of them are caught in the Gulf of Carpentaria. Download Article