Toxicidade do acetamiprido e dimetoato para abelha Scaptotrigona postica latreille, 1804

Abstract

The pollination by insects is vital for terrestrial ecosystems and crop production. There are knowledge gaps regarding the extent and causes related to decline of pollinators, including deforestation, action pathogens and parasitoids and improper use of plant protection products (insecticides, fungicides, herbicides, etc.). Studies to evaluate the toxicity of pesticides (possible contributing agents of the decline of bee populations) should be performed with a wide diversity of species belong to the superfamily Apoidea, such as the native stingless bees. The species Scaptotrigona Postica Latreille, 1804 stands out for being a meliponineo who lives in hollow trees and founding in all tropical areas to subtropical. The objective of this study was to evaluate the acute toxicity (LD50) of acetamiprid and dimethoate insecticides to the native stingless bee S. Postica. In a second stage, based on data LD50 and information on the residue levels found these molecules in floral resources and other plant exudates, sublethal doses established to poison of the bees and verification of lifespan under laboratory conditions. The collection of individuals occurred in natural nests maintained in Umuarama campus of the Federal University of Uberlândia, and the bees transported to the laboratory for carrying out the studies. For Acetamiprid, LD50 data obtained were 173.04, 105.63 and 58.71 μg a.i / bee (equivalent to 0.0118, 0.0072 and 0.0040 μg a.i / mg body weight), respectively for 24, 48 and 72 hours. In the case of dimethoate 24, 48 and 72 hours, the LD50 were respectively 9.71, 2.50 and 0.59 μg a.i / bee (equivalent to 0.00066, 0.00017 and 0.00004 μg a.i / mg of body mass). The results obtained for the survival test showed that sublethal doses equivalent to a 1/100 and 1/1000 that of DL50 did not affect the survival of bees, being identical to the control. In such cases, lethal times 50 (TL50) to the doses mentioned along with the control treatment were 104.03 and 124.21 hours for acetamiprid and dimethoate, respectively. In the case of the organophosphate treatments with a dose of 1/10 of that of LD50 and LD50, it formed with a group of LT50 80.08 hours. For the neonicotinoid, the dose of 1/10 LD50 showed that LT50 intermediate (63.76 hours) and lower life expectancy observed for treatment with the LD50 is 27.29 hours. The results suggest that sublethal doses (1/100 and 1/1000 LD50) may possibly be considered safe S. Postica when only evaluated the survival of bees.