|MadSci Network: Environment/Ecology|
Jeremy, It has been estimated that there are between 2 and 6 million species of Insects on earth. This is a greatly debated number, and indeed one person by the name of Terry Erwin used a technique of 'smoking' insects out of the jungle canopy and based on the number of different insect species that were identified, he extrapolated (an expanded, educated guess) this to mean that up to 30 million different species could be in existence! It is even more difficult to get a good estimate of the rate of death among insect species - but given that the greatest invertebrate populations exist in the rain forests of the world, it is likely that one of the major causes is deforestation. This is particularly damaging to insects because they generally cannot move out of these deforested areas - and the huge reduction in diversity of plant food species available will reduce insect populations. For example, many species of weevil (a type of beetle) have special mouth parts for feeding on particular parts of particular plants. If these food sources are removed the weevils will starve, and that population could become extinct, regardless of how good they are at reproducing (which insects generally do in large volume). So this reminds us how important biodiversity, from the plants to the insects and up the food chain, is to the survival of all species. Compiled in consultation with Rod Hallum, Entomology Technician at the University of Western Ontario, Canada. -Neala MacDonald
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