The abundance of insects has decreased for the last decades in many parts of the world although so far few studies have quantified this reduction because there have only been few baseline studies dating back decades that have allowed comparison of ancient and recent population estimates. Such a paired design is particularly powerful because it reduces or eliminates bias caused by differences in identity and experience of observers, identity of study sites, years, time of season, and time of day, and it ensures identity of sampling procedures.
The “fates of humans and insects are intertwined”, scientists have said, with the huge declines reported in some places only the “tip of the iceberg”. The warning has been issued by 25 experts from around the world, who acknowledge that little is known about most of the estimated 5.5 million insect species. However, enough was understood to warrant immediate action, they said, because waiting for better data would risk irreversible damage.
Many insects, mosses and lichens in the UK are bucking the trend of biodiversity loss, according to a comprehensive analysis of over 5,000 species led by UCL and the UK Centre for Ecology & Hydrology (UKCEH). The researchers say their findings on UK biodiversity between 1970 and 2015, published in Nature Ecology & Evolution, may provide evidence that efforts to improve air and water quality could be paying off.
Two scientific studies of the number of insects splattered by cars have revealed a huge decline in abundance at European sites in two decades. The research adds to growing evidence of what some scientists have called an “insect apocalypse”, which is threatening a collapse in the natural world that sustains humans and all life on Earth. A third study shows plummeting numbers of aquatic insects in streams.
Neonicotinoid insecticides, also known as neonics, are doing more than killing bees and other insects in record numbers, according to a report issued last month by the Natural Resources Defense Council, an international environmental advocacy group. Neonics, the council says, are contaminating New York State’s soil and water and “hollowing out ecosystems from the bottom up.”
A team of scientists from the United Kingdom, Brazil, and New Zealand tracked dung beetles in 30 forest plots scattered throughout the Brazilian state of Pará from 2010 to 2017. In total, they counted more than 14,000 dung beetles from 98 species. They also monitored how effectively the beetles were moving dung out of the plots, and how many seeds they were dispersing.
Ob Bachstelze (Motacilla alba), Wiesenpieper (Anthus pratensis) oder Rauchschwalbe (Hirundo rustica): Die Zahl der von Insekten lebenden Vögel ist in den vergangenen 25 Jahren europaweit deutlich zurückgegangen. Laut einer im Fachjournal Conservation Biology veröffentlichten Studie sank sie durchschnittlich um 13 Prozent. Rund die Hälfte aller Vogelarten in Europa ernährt sich von Insekten. Noch erschreckendere Zahlen hatte vor zwei Monaten die Naturschutzorganisation Nabu (Naturschutzbund Deutschland) unter Verweis auf eine Zählung des European Bird Census Council genannt.
The emergence of Hexagenia limbata mayflies, throughout the Great Lakes and parts of the mid-Atlantic region, is nearly a religious event in angling circles. Each year in early June, these enormous mayflies blanket the landscape, emerging by the billions each night, smothering waterways, riverbanks, roadways and more with thousands of tons of trout-candy biomass. Not long ago, these historic and essential emergences were almost wiped out. By 1970, Hexagenia were gone from large swaths of the Midwest.
The May 2019 newsletter of the Saitama Ecosystem Conservation Society describes how, before the introduction of neonicotinoids in the 1990s, numberless brilliant red akiakane or autumn darter dragonflies could be seen around rice fields in the fall. Experiments by Japanese dragonfly expert Tetsuyuki Ueda of Ishikawa Prefectural University showed how the pesticides reduced the number of surviving dragonfly nymphs to a small fraction, and that the chemicals persist for years in the soil of rice paddy fields.