Overige insecten

In a recent issue of the journal Science, Dave Goulson and colleagues presented a review entitled “Bee declines driven by combined stress from parasites, pesticides, and lack of flowers”. This stimulated Jaboury Ghazoul to submit a letter to Science criticising the Goulson et al. paper from a number of perspectives, but particularly the paucity of the evidence base for pollinator declines. Dave and his co-authors robustly responded to that letter, as you might imagine. In some respects this was an unsatisfactory exchange, however, as the focus was largely on agricultural pollinators, rather than pollinators of all plants (including the majority non-cultivated species) and I think that (perhaps with more space?) Dave could have outlined the evidence in more depth. The most striking statement in Jaboury’s letter was that the “evidence for pollinator declines is almost entirely confined to honeybees and bumblebees in Europe and North America”. Now, even given the fact that Jaboury was possibly referring specifically to agricultural pollinators, that is a very extreme statement to make. Underlying it is the suggestion that global concerns about declining pollinator biodiversity (a subject I’ve discussed repeatedly on this blog) is underpinned by a taxonomically and geographically thin evidence base. Is that really true? I don’t believe so and I think it’s worth presenting a brief overview of the evidence, not least because Dave’s review and the resulting correspondence is pay-walled at the Science site (though if you Google the titles you might, just might, find copies posted on the web…).

Schweizer Gewässer sind mit einem Cocktail von Pestiziden belastet. Manche dieser Substanzen wie Insekten- und Pilzgifte würden bei den Überwachungsprogrammen zu wenig beachtet, urteilen nun Forschende in einer in der Fachzeitschrift «Aqua Gas» veröffentlichten Studie. Der Grund ist laut den Wissenschaftlern der Wasserforschungsanstalt Eawag, dass Insektizide und Fungizide in Gewässern meist in geringeren Konzentrationen vorliegen als Unkrautvernichter (Herbizide). Dadurch waren sie bislang schwerer nachzuweisen. Doch seien gerade Insektizide sehr toxisch und vermutlich der Grund, warum es in Flüssen oft keine Insekten mehr gibt. Das Projekt «Nawa Spez» hatte bereits letztes Jahr zu Tage gefördert, dass Schweizer Flüsse mit zahlreichen Pflanzenschutzmitteln verunreinigt sind. Dafür waren fünf typische Schweizer Bäche auf Pestizide untersucht worden. Im aktuellen Artikel setzt sich das Team um Juliane Hollender nun detaillierter mit den Insekten- und Pilzgiften auseinander und bezieht alle wichtigen Insektizidgruppen ein, wie die Umweltchemikerin erklärte.

A study led by Purdue University Entomology Professor Michael Scharf, Ph.D. finds that small doses of imidacloprid, a neonicotinoid pesticide, can halt the normal functioning of termite behavior, leaving colonies vulnerable to disease and eventual death. While this effect may be celebrated by the pesticide industry as a victory for termite control, it has serious implications for the use of imidacloprid and other neonicotinoid pesticides on all eusocial insects, such as ants and bees.

The black swift (Cypseloides niger), a bird that nests in cliff-side habitats often associated with waterfalls and found in Banff National Park, is on the brink of extinction in Canada. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) met in Quebec April 26 to May 1 to examine the status of 20 species, ranging from lichen and fish to whales and wolves. The black swift, found in British Columbia and extreme western Alberta, was assessed as endangered. COSEWIC scientists say the black swift has experienced a large population decline over recent decades in the United States and in Canada, like many other birds that specialize on a diet of flying insects.They say the Canadian population appears to have declined by more than 50 per cent over a 40-year period between 1973 and 2012, now at an estimated 15,000 to 60,000 mature individuals.