Butterflies

A widespread loss of pollinating insects in recent decades has been revealed by the first national survey in Britain, which scientists say “highlights a fundamental deterioration” in nature. The analysis of 353 wild bee and hoverfly species found the insects have been lost from a quarter of the places they were found in 1980. A third of the species now occupy smaller ranges, with just one in 10 expanding their extent, and the average number of species found in a square kilometre fell by 11.

Senckenberg-Wissenschaftler Thomas Schmitt hat in einem deutsch-polnischen Team die Auswirkungen verschiedener Landnutzungsmodelle auf die Schmetterlingsfauna untersucht. Die Forschenden zeigen, dass es auf Wiesen mit angrenzender intensiver Landwirtschaft nicht einmal die Hälfte der Tagfalterarten gibt, wie auf Flächen in Naturschutzgebieten. Die Zahl der Individuen sinkt sogar auf ein Drittel ab. In ihrer kürzlich im Fachjournal „Insect Conservation and Diversity“ erschienenen Studie unterstreichen die Wissenschaftler*innen die Notwendigkeit einer umweltverträglicheren Landwirtschaft.

Western monarch butterflies spend the winter in more than 300 forested groves along the California coast, including large populations in Riverside and Los Angeles counties, Pacific Grove, Monterey and at Natural Bridges State Beach in Santa Cruz. They can normally be seen from November to March. With the number of butterflies declining rapidly, here are four things governments and the public can do to help:

Protect and manage California overwintering sites.

Chemical agriculture is destroying the ecosystems that sustain all life. Pesticides are a key culprit in the decline of bees, butterflies and other pollinators — leading some scientists to warn of a “second silent spring.” , Pesticides wreak havoc on the soil by killing the organisms that are the basis of soil life. And they pollute rivers, lakes and oceans, leading to fish die-offs.

The number of monarch butterflies turning up at California's overwintering sites has dropped by about 86 percent compared to only a year ago, according to the Xerces Society, which organizes a yearly count of the iconic creatures. That’s bad news for a species whose numbers have already declined an estimated 97 percent since the 1980s. Each year, monarchs in the western United States migrate from inland areas to California’s coastline to spend the winter, usually between September and February.

A 37-year survey of monarch populations in North Central Florida shows that caterpillars and butterflies have been declining since 1985 and have dropped by 80 percent since 2005. This decrease parallels monarchs' dwindling numbers in their overwintering grounds in Mexico, said study co-author Jaret Daniels, program director and associate curator of the Florida Museum of Natural History's McGuire Center for Lepidoptera and Biodiversity.

Fears are growing for the small tortoiseshell butterfly Aglais urticae after this once-common garden insect continued its baffling decline despite the hot summer proving a boon to most species. The small tortoiseshell suffered its worst summer in the history of the Big Butterfly Count with sightings falling by 32% compared with last year, according to the charity Butterfly Conservation.

We measured uptake and dissipation of soil-applied imidacloprid and dinotefuran in nectar and leaves of 2 woody plant species, a broadleaf evergreen tree (Ilex attenuata) and a deciduous shrub (Clethra alnifolia), to assess concentrations to which pollinators and pests might be exposed in landscape settings. Three application timings, autumn (postbloom), spring (prebloom), and summer (early postbloom), were evaluated to see if taking advantage of differences in the neonicotinoids’ systemic mobility and persistence might enable pest control while minimizing transference into nectar.

Since 1990, butterfly numbers have dropped by 58 per cent in woods, a government study has found. The report was published in June 2018 by the Department for environment, food and rural affairs (Defra). Woodland species that are struggling include the brown argus, common blue, peacock and purple hairstreak .In response to the report, charities have claimed that reform is needed to the country's farming laws in order to protect the environment in the wake of Brexit. They say the latest figures offer more evidence to support expert predictions of an 'ecological Armageddon'.

Das Insektensterben trifft nach Angaben der Landesstiftung Natur und Umwelt (Lanu) auch Schmetterlinge. In Sachsen seien bereits je 14 Prozent der 125 heimischen Tagfalterarten ausgestorben und davon bedroht, teilte die Lanu am Freitag bei der Eröffnung der Schmetterlingssaison in Zwickau mit. Auch einst häufige Arten würden seltener.