›› 2017, Vol. 60 ›› Issue (11): 1300-1306.doi: 10.16380/j.kcxb.2017.11.008

• RESEARCH PAPERS • Previous Articles     Next Articles

Effects of field realistic doses of imidacloprid on learning and memory of Apis mellifera ligustica (Hymenoptera: Apidae) workers

YU Tian-Tian, HE Jing-Fang, LUO Ting-Ting, DONG Ying-Bo, LI Zhi-Guo*, SU Song-Kun   

  1. (College of Bee Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China)
  • Online:2017-11-20 Published:2017-11-20

Abstract: 【Aim】 Imidaclorprid is the most widely used pesticide among neonicotinoid pesticides and acts on the brain’s nicotinic acetylcholine receptor of honey bees. In addition, imidaclorprid interferes with the growth and development of honey bees. This study aims to clarify the effects of imidacloprid at field realistic doses on learning and memory of honey bees, so as to provide evidence for the prediction of the widespread death of colonies in some areas and reference for the safe use of neonicotinoid pesticide in the field. 【Methods】 Newly emerged 1-day-old bees (Apis mellifera ligustica) were marked by paint marker. They were kept in the colony for 8 d, and then were reared within boxes (50 individuals/box) in an incubator with constant temperature and humidity (30±1℃, relative humidity 40%±10%, dark) for 9 d. Meanwhile, the treatment group fed 30% (w/v) syrup containing 0.01 ng/μL of imidacloprid ad libitum, while the control group fed 30% (w/v) syrup containing 0.01 ng/μL of acetone ad libitum. Following being trained with three paired stimulations (lemon odor paired with sucrose stimulation) performed using a customized device, the 18-day-old bees were used for the olfactory associative learning and memory experiments. 【Results】 There was no significant difference in the mortality between the treatment group and the control group during the 9-day feeding period (P>0.05). In the three olfactory associative learning experiments, the learning ability of bees of the treatment group in the 2nd and 3rd experiments was significantly reduced (P<0.01) compared with the control group, but there was no difference in the 1st experiment [proboscis extension response (PER)%=0]. After 24 h, the proboscis extension reflex rate was not significantly different between the treatment and control groups (P>0.05). 【Conclusion】 The results demonstrate that 0.01 ng/μL imidacloprid does not cause acute death of honey bees. This dose of imidacloprid does not affect the 24 h long-term memory of honey bees, but impairs learning ability of honey bees significantly and may even adversely affect the foraging behavior of honey bees.

Key words:  Apis mellifera ligustica; neonicotinoid pesticides, imidacloprid, field realistic dose, learning behaviors, memory behaviors, proboscis extension response