In vitro bioassay of locomotor activity with sub-lethal doses of glyphosate on honeybee larvae

VÁZQUEZ, DIEGO EDUARDO; FARINA, WALTER MARCELO

Montevideo

Congreso; XII International Congress of Neuroethology; 2016

As the most relevant pollinator in agricultural settings the honeybee (Apis mellifera) is exposed to many agrochemicals, in which the herbicide glyphosate (GLY) is one of the most important worldwide. To detect putative adverse effects of this herbicide on behaviour, we develop a novel in vitro bioassay to analyse locomotor activity in preimaginal individuals. Honeybee larvae were reared in vitro post-hatching to control nutritional status and amount of GLY administered by contaminated food (treatments:0, 2.5 and 5 a.e. mg/L of GLY). We assessed individually 30 larvae on the fifth instar with complete food intake (110 μl) into Petri dishes at an incubator (34 ºC and 95% RH). Thus, we recorded the position of individual larvae along a bioassay period of 20 hours. About 80% of control larvae were active after one hour and never ceased its activity later. At the end of the test whole larvae had moved, although a reduced locomotor activity was detected for larvae exposed to GLY. This was observed for variables such as the proportion of activation, inactivation and displacement. This is the first experimental approach to evaluate honeybee larval activity through an in vitro bioassay and it seems to be suitable to detect behavioral changes cause by pesticides.