Overige insecten

When they’re not dining on the population explosions of caterpillars, they eat other insects, frogs, lizards, crickets, cicadas and other streamside dwellers. They’ve almost vanished from the Southwest — including Arizona. So the U.S. Fish and Wildlife Service wants to list the wide-ranging, quickly-disappearing, stream-loving western yellow-billed cuckcoo (Coccyzus americanus) as an endangered species — likely adding one more layer of protection for — and restrictions on — streams in Rim Country. The federal government has proposed listing 80 protected streamside areas as critical habitat for the robin-sized bird, including Tonto Creek, the Verde River and other small streams like the East Verde, Fossil Creek and other Rim Country streams. Population surveys suggest the Western Cuckcoo continues to decline by about 1.5 percent annually. The estimated 15,000 breeding pairs in California in the late 19th century had declined to about 30 pairs by 1986. The thousands of pairs in Arizona had declined to 200 pairs in the same period. Biologists aren’t sure how many pairs remain in the southwest now.

Neonicotinoids are the most widely used insecticides world-wide, but their fate in the environment remains unclear, as does their potential to influence non-target species and the roles they play in agroecosystems. We investigated in laboratory and field studies the influence of the neonicotinoid thiamethoxam, applied as a coating to soya bean seeds, on interactions among soya beans, non-target molluscan herbivores and their insect predators. In the laboratory, the pest slug Deroceras reticulatum was unaffected by thiamethoxam, but transmitted the toxin to predaceous beetles (Chlaenius tricolor), impairing or killing >60%. In the field, thiamethoxam-based seed treatments depressed activity–density of arthropod predators, thereby relaxing predation of slugs and reducing soya bean densities by 19% and yield by 5%. Neonicotinoid residue analyses revealed that insecticide concentrations declined through the food chain, but levels in field-collected slugs (up to 500 ng g−1) were still high enough to harm insect predators. Our findings reveal a previously unconsidered ecological pathway through which neonicotinoid use can unintentionally reduce biological control and crop yield. Trophic transfer of neonicotinoids challenges the notion that seed-applied toxins precisely target herbivorous pests and highlights the need to consider predatory arthropods and soil communities in neonicotinoid risk assessment and stewardship.

In a letter submitted for today’s White House “listening sessions” deadline, over 100 scientists from diverse disciplines (including Dutch toxicologist Henk Tennekes) cited the growing body of evidence that neonicotinoids and other systemic pesticides harm bees. These scientists called on leaders of President Barack Obama’s Pollinator Health Task Force to take action on pesticides to protect and promote healthy populations of bees and other pollinators.

Nature magazine brings a chilling article on the horrendous effects of agricultural chemicals in pesticides on invertebrates and the soil. The key words: even at 'safe' levels. The results were drawn from several studies in different continents and reveal that in polluted areas, up to forty-two per cent of species were lost as a result of harmful chemicals. "Pesticides spark broad biodiversity loss", written by Sharon Oosthoek, tells a sorry tale of the effects of pesticides on biodiversity. The conclusion is that the use of pesticides has caused a sharp decline in the biodiversity of invertebrates living in streams. Studies carried out in Germany and France in Europe and in Australia showed a dramatic decline in species such as mayflies and dragonflies. Quoting he study published in the Proceedings of the National Academy of Sciences, Sharon Oosthoek went on to state some shocking details: the studies were carried out in 23 streams in Germany, 16 in France and 24 in Australia, classifying them in three categories: uncontaminated, slightly contaminated and highly contaminated. In the last category, there were up to 42% fewer species than those found in the uncontaminated group of streams in Europe, while the figure in Australia was a decrease of 27%. More seriously still, the article goes on to claim, the decrease in biodiversity occurred even at levels which scientists state to be "environmentally protective".