Overige insecten

Die Schwalbe sollte einst den Höfen Glück bringen, unter deren Dächern sie ihre Nester baute. Doch inzwischen werden die Vögel mit dem charakteristischen langen Schwanz immer seltener. Manfred Weber aus Stadelhofen kennt die Gründe und hat auch ein paar Tipps parat, was man für die bedrohte Vogelart tun kann. Bald ein Sommer ohne Schwalben? Es werden jedenfalls immer weniger. Vor etwa 20 Jahren habe es in der Industriestraße in Stadelhofen, wo Manfred Weber wohnt, eine Schwalbenkolonie mit rund 50 Nestern gegeben, jetzt seien davon noch zwei bis drei übrig geblieben. Die Schwalben sind standorttreu und kehren nach dem Winter im Süden immer wieder zum gleichen Ort zurück. Daher ist die geringe Zahl der Vögel ein deutliches Indiz dafür, dass es immer weniger Schwalben gibt. Manfred Weber, der sich im Naturschutzbund Nabu Offenburg für Artenschutz einsetzt, kann erklären, warum es immer weniger Schwalben gibt. »Ein Grund ist der Nahrungsmangel. Schwalben fressen Fluginsekten wie Schnaken und Fliegen. Leider gibt es immer weniger Insekten«, sagt er.

The world’s population of creepy crawlies has fallen by nearly half – but that is bad news for us, experts warn. A study published in the journal Science, reveals that the number of slugs, spiders, worms and other invertebrates has fallen by 45 per cent over the past 35 years as the human population has doubled. Experts fear this will harm the planet as creepy crawlies play an important role in pollinating crops, pest control, decomposition and ensuring soil remains packed with nutrients, as well as water filtration. In the UK the number of beetles, butterflies, bees and wasps has fallen by up to 60 per cent. Experts warn that fewer insects would have a huge effect on crop production as up to 75 per are pollinated by insects, amounting to around 10 per cent of the world's food supply. And the cost of pest control without natural predators could be more than £2.6 billion pounds in the United States alone. Scientists fear a drop in the insect population could also spark a decline in birds, which prey on pests that damage crops, and amphibians, which help keep water supplies free from algae. Decreasing invertebrate numbers are also known to compromise food production due to reduced pollination, seed dispersal and insect predation.

New findings published in the journal Environmental Science & Technology investigate the use of insecticides--specifically neonicotinoids--and their effects on the decline of the honey bee population. Although sunlight plays an important role in degrading pollutants, its effects on neonicotinoids may diminish, particularly when exposed to water. In order to protect crops from pests, including whiteflies, beetles and termites, neonicotinoids are often used as a popular protection tool among farmers. However, they end up washing into the surface waters and soil. For the study, researchers looked to investigate the sunlight's effects on these insecticides in the water. They tested five neonicotinoids in water under simulated sunny conditions and within minutes, three degraded considerably, according to researchers. And while two took a few days to break down, a depth of just 3 inches of water was enough to shield at least one, thiamethoxam, from the sun. The researchers noted that at a persistent rate with shallow depth, this could increase insecticide exposure to both aquatic life and other wildlife exposure.

It is a good question, and many local people are wondering about the answer. Biologists confirm that swallow numbers have dropped precipitously in the past 50 years, by up to 90 per cent. Researchers describe the decline as “shocking.” The numbers of barn swallows, trees swallows and purple martins have collapsed especially rapidly. “Maybe (the time) when insects are abundant is no longer when swallows are breeding,” suggested Tara Imlay of Dalhousie University. It is as if the peak breeding period, and peak food supply, are no longer in sync. In Ontario, the barn swallow population has fallen by close to 70 per cent since 1966. “The decline is especially alarming because swallows used to be so abundant and widespread,” said expert Bridget Stutchbury. Biologists estimate that in North America about 50 per cent of all songbirds have vanished in the past 50 years.

One of the most vivid memories Jeff Gordon had growing up in Delaware was the sight of moths at night. “When I was just a kid in the mid to late 60s,” said Gordon, “my grandparents bought a place on Rehoboth Bay, at that time, it was really out in the woods. And I remember one of the magical things as a kid, in the evenings, we had a screen porch and the lights there would attract, just this carpet of moths, and not just tiny little brown moths, there were luna moths, and rosy maple moths and prometheus and polyphemus and big, spectacular, intricately colored moths. It’s really one of the things I feel most strongly awakened an interest in nature in me, it set me on a path that I followed to the rest of my life.” Jeff Gordon is now the president of the American Birding Association, a national birdwatching organization that’s headquartered in Delaware City. These days, he doesn’t see as many moths as he used to when he was a kid. “It’s just so radically different now, the numbers and diversity,” said Gordon. “I think most of those species are still present, but it used to be like a blizzard. Now, it’s a few flurries. I hate to say this but unfortunately, one of the recent encounters I had with the silk moths in that area was finding one flopping around under a 24-hour gas station.”

Anthropogenic declines of animal pollinators and the associated effects on human nutrition are of growing concern. We quantified the nutritional and health outcomes associated with decreased intake of pollinator-dependent foods for populations around the world. We assembled a database of supplies of 224 types of food in 156 countries. We quantified nutrient composition and pollinator dependence of foods to estimate the size of possible reductions in micronutrient and food intakes for different national populations, while keeping calorie intake constant with replacement by staple foods. We estimated pollinator-decline-dependent changes in micronutrient-deficient populations using population-weighted estimated average requirements and the cutpoint method. We estimated disease burdens of non-communicable, communicable, and malnutrition-related diseases with the Global Burden of Disease 2010 comparative risk assessment framework. Assuming complete removal of pollinators, 71 million (95% uncertainty interval 41–262) people in low-income countries could become newly deficient in vitamin A, and an additional 2·2 billion (1·2–2·5) already consuming below the average requirement would have further declines in vitamin A supplies. Corresponding estimates for folate were 173 million (134–225) and 1·23 billion (1·12–1·33). A 100% decline in pollinator services could reduce global fruit supplies by 22·9% (19·5–26·1), vegetables by 16·3% (15·1–17·7), and nuts and seeds by 22·1% (17·7–26·4), with significant heterogeneity by country. In sum, these dietary changes could increase global deaths yearly from non-communicable and malnutrition-related diseases by 1·42 million (1·38–1·48) and disability-adjusted life-years (DALYs) by 27·0 million (25·8–29·1), an increase of 2·7% for deaths and 1·1% for DALYs. A 50% loss of pollination services would be associated with 700 000 additional annual deaths and 13·2 million DALYs. Declines in animal pollinators could cause significant global health burdens from both non-communicable diseases and micronutrient deficiencies.

Pope Francis slams both GMOs and pesticides in a draft of his major environmental document that was leaked Monday. On pesticides Pope Francis states; “We get sick, for example, due to inhalation of large amounts of smoke produced by fuels used for cooking and heating. This is added to by….fertilizers, insecticides, fungicides, herbicides and toxic pesticides in general. Technology that is linked to finance, claims to be only solving problems…this solves a problem by creating others. “It creates a vicious circle in which the intervention of the human being to solve a problem often worsens the situation further. For example, many birds and insects die out as a result of toxic pesticides created by technology, they are useful to agriculture itself, and their disappearance will be compensated with another technological intervention that probably will bring new harmful effects… looking at the world we see that this level of human intervention, often in the service of finance and consumerism, actually causes the earth we live in to become less rich and beautiful, more and more limited and gray, while at the same time the development of technology and consumerism continues to advance without limits.”

Two species, the fathead minnow Pimephales promelas and the amphipod Hyalella azteca, were tested to examine acute toxicity to two insecticides, cyfluthrin and imidacloprid individually and as a mixture. Cyfluthrin was acutely toxic to P. promelas and H. azteca with EC50 values and 95 % confidence intervals of 0.31 µg L−1 (0.26–0.35 µg L−1) and 0.0015 µg L−1 (0.0011–0.0018 µg L−1), respectively. Imidacloprid was not acutely toxic to P. promelas at water concentrations ranging from 1 to 5000 µg L−1, whereas it was toxic to H. azteca with a EC50 value of 33.5 µg L−1 (23.3–47.4 µg L−1). For the P. promelas mixture test, imidacloprid was added at a single concentration to a geometric series of cyfluthrin concentrations bracketing the EC50 value. A synergistic ratio (SR) of 1.9 was found for P. promelas, which was calculated using the cyfluthrin-only exposure and mixture-exposure data. Because cyfluthrin and imidacloprid were toxic to H. azteca, the mixture test was designed based on an equipotent toxic unit method. Results from the mixture test indicated a model deviation ratio (MDR) of 1.7 or 2.7 depending on the model. Mixture test results from the simultaneous exposure to cyfluthrin and imidacloprid with both species indicated a greater than expected toxic response because the SR or MDR values were >1. Because these two insecticides are commonly used together in the same product formulations, nontarget species could be more affected due to their greater-than-additive toxicity observed in the current study.