Insecticiden

Neonicotinoid pesticides, such as the widely used compound imidacloprid, are suspected to impair cognitive capacity, behaviour, and fitness of a number of non-target species. We tested whether sublethal imidacloprid concentrations alter the foraging and aggression behaviour of two European ant species. Even though the nestmate-recruitment of Lasius niger was not affected by pesticide exposure, these ants required more time to become active and the number of foraging workers was lower than in sub-colonies not exposed to imidacloprid.

There is a growing concern that exposure to environmental chemicals in early life may interfere with brain development. In particular, neonicotinoid pesticides have drawn considerable attention. As a pesticide class, neonicotinoids are designed to overstimulate insect nicotinic acetylcholine receptors (nAChRs). These pesticides were previously thought to be relatively harmless to mammalian species because of their low binding affinities to mammalian nAChRs.

The ability to forage and return home is essential to the success of bees as both foragers and pollinators. Pesticide exposure may cause behavioural changes that interfere with these processes, with consequences for colony persistence and delivery of pollination services. We investigated the impact of chronic exposure (5–43 days) to field-realistic levels of a neonicotinoid insecticide (2·4 ppb thiamethoxam) on foraging ability, homing success and colony size using radio frequency identification (RFID) technology in free-flying bumblebee colonies.

Neonicotinoids are implicated in the decline of bee populations. As agonists of nicotinic acetylcholine receptors, they disturb acetylcholine receptor signaling leading to neurotoxicity. Several behavioral studies showed the link between neonicotinoid exposure and adverse effects on foraging activity and reproduction. However, molecular effects underlying these effects are poorly understood. Here we elucidated molecular effects at environmental realistic levels of three neonicotinoids and nicotine, and compared laboratory studies to field exposures with acetamiprid.

A strong immune defense is vital for honey bee health and colony survival. This defense can be weakened by environmental factors that may render honey bees more vulnerable to parasites and pathogens. Honey bees are frequently exposed to neonicotinoid pesticides, which are being discussed as one of the stress factors that may lead to colony failure.

Der Killer ist erst seit wenigen Jahren in Europa, doch er richtet verheerende Schäden an. Ein aggressiver Pilz aus Asien befällt die Haut von Salamandern und Molchen und tötet die Tiere in kurzer Zeit. In den Niederlanden sind zwischen 2010 und 2013 99,9 Prozent der Salamander ausgestorben, berichten Forscher. Und der Erreger namens „Bs“ (Batrachochytrium salamandrivorans) breitet sich weiter aus. Viele Salamander- und Molcharten Europas könnten ausgelöscht werden, befürchten Amphibien-Experten wie Dirk Schmeller vom Helmholtz-Zentrum für Umweltforschung (UFZ) in Leipzig.

The decline of pollinators worldwide is of growing concern and has been related to the use of plant protecting chemicals. Most studies have focused on three neonicotinoid insecticides, clothianidin, imidacloprid and thiamethoxam, currently subject to a moratorium in the EU. Here we focus on thiacloprid, a widely used cyano-substituted neonicotinoid thought to be less toxic to honey bees and of which use has increased in the last years. Honey bees (Apis mellifera carnica) were exposed chronically to thiacloprid in the field for several weeks at a sublethal concentration.