Respostas comportamentais de Nannotrigona sp. a inseticidas de origem sintética e natural

Abstract

The bee population in the world is declining. Among the factors associated with the decline of these pollinators is the use of insecticides, especially neonicotinoids when they are combined with honey bees. This fact has drawn attention to native bees. A change to selective insecticides can reduce this impact, and the essential oil (EO) of Lippia sidoides and its major compounds appear as potential insecticides. In this work, the lethal and sublethal effects of the EO of L. sidoides were evaluated for their major compounds: thymol, r-cymene, and (E)-caryophyllene, as well as for the insecticides spinetoram, deltamethrin, and imidacloprid in native Nannotrigona sp. bees. All of the insecticides were more toxic than the EO and its major compounds. The behavior of the bees was significantly altered by all of the treatments. The EO caused avoidance behavior by the untreated individuals in relation to the treated individuals. In the tests of locomotion and flight guidance, imidacloprid and deltamethrin were the treatments that most decreased the proportion and the speed of arrival of the individuals to the light source at both evaluation times (3 and 24h) after the exposition to the treatments. On the other hand, the EO, its isolated major compounds, and spinetoram presented intermediate values. Spinetoram, thymol, and (E)-caryophyllene reduced the proportion of individuals who reached for the light source from 3 to 24 hours after the exposition. These results are evidence for the greater safety of these products for the pollinators. However, further studies are needed to confirm this safety for other non-target organisms.