Imidacloprid alters foraging and decreases bee avoidance of predators

PLoS One. 2014 Jul 15;9(7):e102725. doi: 10.1371/journal.pone.0102725. eCollection 2014.

Abstract

Concern is growing over the effects of neonicotinoid pesticides, which can impair honey bee cognition. We provide the first demonstration that sublethal concentrations of imidacloprid can harm honey bee decision-making about danger by significantly increasing the probability of a bee visiting a dangerous food source. Apis cerana is a native bee that is an important pollinator of agricultural crops and native plants in Asia. When foraging on nectar containing 40 µg/L (34 ppb) imidacloprid, honey bees (Apis cerana) showed no aversion to a feeder with a hornet predator, and 1.8 fold more bees chose the dangerous feeder as compared to control bees. Control bees exhibited significant predator avoidance. We also give the first evidence that foraging by A. cerana workers can be inhibited by sublethal concentrations of the pesticide, imidacloprid, which is widely used in Asia. Compared to bees collecting uncontaminated nectar, 23% fewer foragers returned to collect the nectar with 40 µg/L imidacloprid. Bees that did return respectively collected 46% and 63% less nectar containing 20 µg/L and 40 µg/L imidacloprid. These results suggest that the effects of neonicotinoids on honey bee decision-making and other advanced cognitive functions should be explored. Moreover, research should extend beyond the classic model, the European honey bee (A. mellifera), to other important bee species.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bees / drug effects
  • Bees / physiology*
  • Escape Reaction / drug effects
  • Feeding Behavior / drug effects
  • Food Chain
  • Imidazoles / toxicity*
  • Insecticides / toxicity*
  • Neonicotinoids
  • Nitro Compounds / toxicity*
  • Wasps / physiology

Substances

  • Imidazoles
  • Insecticides
  • Neonicotinoids
  • Nitro Compounds
  • imidacloprid

Grants and funding

This work was supported by the Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, and the CAS 135 program (XTBGT01) of Chinese Academy of Science, China National Research Fund (31260585) to Ken Tan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.