PDF《mellifera》

1 (Nmdar1). GluRA is widely distributed in the central nervous system in the Western honeybee and is considered a metabotropic glutamate receptor gene that affects long-term learning and memory ability of bees. It is a key neurotransmitter in learning and memory processes (Danbolt 2001;

Kucharski et?al. 2007). The Nmdar recep- tor is one of the important excitatory amino acid receptors in the central nervous system. It is an important ionotropic * Xiao?bo Wu [email protected]

1 Honeybee Research Institute, Jiangxi Agricultural University, Nanchang?330045, China

2 Department of?Biological Sciences, Macquarie University, Sydney, NSW?2109, Australia

60 Archives of Environmental Contamination and Toxicology (2018) 75:59C65 receptor involved in the processes of learning and memory (Zachepilo et?al. 2008;

Morris et?al. 1991). The intention is to establish what dose range of lambda-cyhalothrin can have deleterious effects on bees and the nature of these effects. Materials and?Methods Insect and?Lambda?Cyhalothrin Preparation The Western honey bee A. mellifera was used throughout this study. Honey bee colonies were maintained at the Hon- eybee Research Institute, Jingxi Agricultural University, Nanchang, China (28.46°N, 115.49°E). Lambda-cyhalothrin was provided by the Zhejiang Wei- erda Chemical Co. The standard solution was prepared by adding distilled water to lambda-cyhalothrin, then diluting with 50% sucrose water to corresponding concentrations of 1/8 ?LC50 (0.7459?ppm), 1/4 ? LC50 (1.4919?ppm), and 1/2 ?LC50 (2.9839?ppm), based on the ? LC50 results for lambda- cyhalothrin estimated by Zhou et?al. (2014). Effects of?Lambda?Cyhalothrin on?the?Lifespan of?Apis mellifera Worker Bees Approximately

700 newly emerged worker bees from one colony were randomly divided into four cages (cage size 140?*?150?*?220?mm, N?~?200 bees per cage) and fed differ- ent concentrations of lambda-cyhalothrin syrups (1/2LC50, 1/4LC50, 1/8LC50) for 3?days, respectively, whereas bees fed only 50% sucrose water were used as a control group. After 3?days, all cages of bees were fed 50% sucrose water without any lambda-cyhalothrin. We replicated this experi- ment three times using newly emerged workers from three different colonies. Syrup was replaced each day, and records were kept of mortality in each group until all of the bees died (50?days maximum). Effects of?Lambda?Cyhalothrin on?Learning and?Memory Bees were prepared and treated as described above. The proboscis extension response (PER) conditioning experi- ment began on the seventh day. Thirty bees from each group were collected from cages and briefly immobilized on ice for 5?min. Each bee was fixed in a metal tube with thin strips of GAFFA tape so that the whole body was immobilized, but the two forelegs and head were free. Then, the bees were fed with 50% sugar solution and left to recover in an incubator at a constant temperature of 28?°C. Bees were trained and tested for olfactory learning with PER conditioning according to the method of Letzkus et?al. (2006). The main modification of this standard method for our protocol was the use of two scents: limonene and vanilla, associated with a rewarding and punishing uncon- ditioned stimulus respectively. One stimulus was a scent mixed in a 1?M sugar solution (reward). The other stimulus was the different scent mixed with saturated salt solution (punishment). We first presented the reward stimulus for 5?s by holding the scented drop 1C2?cm in front of the bee. The antennae were then briefly touched with the stimulus drop, thus associating the scent with the sugar reward. If the bee extended her proboscis, she received a food reward in the form of the sugar solution. Next, the same proce- dure was performed with the punishing stimulus. Six min later, the bees were trained again with both the rewarding and punishing stimuli. Each bee received three training trials with each stimulus. After training, the honeybees were fed 2C3 drops of 1?M sugar solution and returned to the incubator for overnight storage. Tests were performed on the morning after the training was performed. Each bee was tested three times with the punishing and reward scents only (bees were not able to contact either solution with their proboscis and so could not ........