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Insects are the best example of biodiversity.
They represent the third of the living species and scientists discover new specie every day.
One group in particular has survived through many geological events : the insects.
While climate was changing regularly, they were able to adjust and develop.
Today, it is the human’s impact that is presenting a threat to insects.
With Philippe Le Gall, entomologist from IRD, we try to understand how, in this area of Cameroun mountains, the living is always in motion...
The coleoptera group accounts for about 350,000 species which is about a fourth of the total known species of one million.
Using the insects and their major biodiversity, availability and size, scientists have now a fundamental model that they can use for their research.
443 - Amazon forest: the first large-scale inventory has revealed the hyper-dominance of 227 tree species
An international study, involving scientists from IRD, INRA, CNRS, CIRAD, with the support of the IRD herbarium in French Guiana, recently produced the first large-scale inventory of the trees in the Amazon Basin. The researchers showed that the world's largest tropical rainforest comprises almost 390 billion trees belonging to some 16,000 species. They demonstrated that just 227 species were hyper-dominant, accounting for more than half the trees in the rainforest. The results of the study, which also estimated the number of rare species at 11,000, were published on 18 October 2013 in the journal Science , in the form of a review paper.
Like many other transgenic crops, Bt maize synthesises its own pesticide: a toxic protein produced in its leaves and stems, which kills pests in a matter of days. Perfect… Except when insect populations develop resistance to the toxin! To date, management strategies implemented to delay the evolution of resistance have been successful. Notwithstanding the success of these strategies, IRD scientists and their South African partners have now revealed that a major pest of maize, the moth Busseola fusca , has developed an unusual defense mechanism against Bt toxin in South Africa. By contrast with the usual expectations, this resistance is inherited as a dominant trait, a characteristic that may have contributed to its rapid geographical expansion. This result recently published in the journal PLoS ONE , suggests that insect resistance management should be more finely tuned to local pests and should go beyond the simple implementation of refuges for Bt -susceptible moths.