Imidacloprid Induces Histopathological Damage in the Midgut, Ovary, and Spermathecal Stored Spermatozoa of Queens After Chronic Colony Exposure.

Bee colony health is declining as a result of several factors, including exposure to pesticides. The development and strength of honey bee colonies depend on the reproductive success of queen bees. Because flowers are sources of food for bees, foragers can accidentally collect and carry contaminated pollen and nectar to their hives; and this may compromise the longevity and the life span of individuals. Thus, the present study aimed to observe the action of imidacloprid in the midgut and ovaries of Apis mellifera queens, as well as the effects on sperm stored in their spermatheca. To this end, the apiary was divided into three experimental groups: control, commercial imidacloprid, and active ingredient imidacloprid. For toxicity assays, a sucrose solution containing 1 µg/L of imidacloprid was offered to the colonies for 42 days. A control group received only food in the same period. In both treatments with imidacloprid, the midgut of queens showed modifications in the external musculature and cellular alterations. Such changes could lead to the nonrecovery of the epithelium and subsequently malabsorption of nutrients. Moreover, the digestive cells of queen bees exposed to the commercial imidacloprid presented pyknotic nuclei, suggesting a cell death process. The main alterations observed in the ovaries of these reproductive bees treated with commercial imidacloprid were degeneration and resorption of the ovariole content, which probably affected their fertilization and colony development. There were no significant changes in the spermatozoa morphology for both treatments with imidacloprid, but this insecticide may interfere with the development and reproductive success of A. mellifera colonies because it affects the morphology and function of essential organs for the survival of queens. Environ Toxicol Chem 2022;41:1637-1648. SETAC.

Determination of the Ca, Mn, Mg and Fe in honey from multiple species of stingless bee produced in Brazil.

Stingless Bees (SB) honey is a product used for different purposes, and it is worth highlighting the presence of metallic species, which can have a nutritional or toxic effect, depending on the metal present and/or the amount ingested. Therefore, the objective of this work was to quickly determine Fe, Mn, Mg and Ca in SB honey, using slurry sampling and FAAS of 88 honey samples from different regions of Brazil. The concentrations varied from < LOD to 364 µg g-1 (Ca). The order for average concentration in the samples was Ca > Mg > Mn > Fe. Through the principal component analysis, it was verified that the SB honey analyzed in the present study has higher contents of the evaluated metals than the honey of the species Apis mellifera and SB honey from other Brazilian states. Theoretical calculation demonstrated that there is a little contribution of SB honey to human diet in relation to the metals, being more significative for Mn.