Insecticides

New research published in the journal Proceedings of the Royal Society B has found that wild bumblebee queens are less able to develop their ovaries when exposed to a common neonicotinoid pesticide. The research was conducted by Dr Gemma Baron , Professor Mark Brown of Royal Holloway, University of London and Professor Nigel Raine, (now based at the University of Guelph). The study investigated the impact of exposure to field-realistic levels of a neonicotinoid insecticide (thiamethoxam) on the feeding behaviour and ovary development of four species of bumblebee queen.

Anfang dieser Woche hat Holger Sticht eine kleine Exkursion in die Wahner Heide unternommen. Dort ist Sticht häufiger unterwegs, denn der 45-Jährige ist Landesvorsitzender des Bundes für Umwelt und Naturschutz Deutschland (BUND) im Land und Hobby-Ornithologe. Einen alten Bekannten aber, den er in der Vergangenheit in dem zweitgrößten und artenreichsten Naturschutzgebiet Nordrhein-Westfalens, das nahe Köln gelegen ist, hat er diesmal weder gehört noch gesehen: den Waldlaubsänger (Phylloscopus sibilatrix).

Die Bestände an Hummeln brechen dramatisch ein. Schuld daran sind wie auch beim Bienensterben Neonicotinoide, Insektenvernichtungsmittel. Diese wirken auf die Nervenzellen der Hummeln und sorgen dafür, dass diese weniger Eier legen. Ein Experiment ergab jetzt: Neonicotinoide verringern die Zahl eierlegender Hummelköniginnen um ein Viertel. Das kann zum Kollaps der Hummelpopulationen führen. Britische Forscher schätzten in „Nature Ecology & Evolution“ das Risiko der Hummeln auszusterben auf 28 %.

The widespread contamination of a significant proportion of the planet’s land and water with pesticides is undeniable. While this takes place, innumerable species of animals associated with agricultural landscapes are declining at rates that may put them on the brink to extinction in the span of a lifetime. It is evident, therefore, that our current risk assessment of agrochemicals has failed to protect the environment.

In a new study, biologists at Bielefeld University show the effects of pesticides and how even slight traces lead to long-term damage to beetles. One finding is that leaf beetles lay roughly 35 per cent fewer eggs after coming into contact with traces of a frequently used pesticide: a pyrethroid. The researchers also showed that female offspring develop malformations through the poison. The biologists have published their study in the journal Environmental Pollution.

More than 180 pesticides and their by-products were detected in small streams throughout 11 Midwestern states, some at concentrations likely to harm aquatic insects, according to a new study by the U.S. Geological Survey. The mixtures of pesticides are more complex than previously reported by the USGS—94 pesticides and 89 pesticide byproducts were detected. On average, 52 pesticide compounds were identified in each stream.

The goal of this research was to investigate the effects of the neonicotinoid imidacloprid on the morphological and physiological development of northern bobwhite quail (Colinus virginianus). Bobwhite eggs (n = 390) were injected with imidacloprid concentrations of 0 (sham), 10, 50, 100, and 150 mg/kg of egg mass, which was administered at day 0 (pre-incubation), 3, 6, 9, or 12 of growth. Embryos were dissected, weighed, staged, and examined for any overt structural deformities after 19 days of incubation. The mass of the embryonic heart, liver, lungs and kidneys was also recorded.

The occurrence of pesticides intended for non-agricultural use was investigated in 206 dust samples drawn from vacuum-cleaner bags from residential flats in Italy. The results indicated the presence of imidacloprid (IMI) in 30% of the samples. According to the estimated dust intake in infants/toddlers aged 6–24 months (16–100 mg d−1) and cats (200 mg d−1), it was possible to obtain risk characterization with respect to the Acceptable Daily Intake (ADI) for IMI of 0.060 mg/kg body weight (bw) proposed by EFSA and the chronic Population Adjusted Dose (cPAD) of 0.019 mg/kg bw d−1 by US-EPA.

Imidacloprid (IMD) is the most widely used neonicotinoid insecticide found on environmental surfaces and in water. Analysis of surface-bound IMD photolysis products was performed using attenuated total reflectance Fourier transfer infrared (ATR-FTIR) analysis, electrospray ionization (ESI-MS), direct analysis in real time mass spectrometry (DART-MS), and transmission FTIR for gas-phase products. Photolysis quantum yields (ϕ) for loss of IMD were determined to be (1.6 ± 0.6) × 10–3 (1s) at 305 nm and (8.5 ± 2.1) × 10–3 (1s) at 254 nm.