Interaction between pesticides and Nosema infection in Africanized Apis mellifera: biological effects and detection of cellular biomarkers

Abstract

The honey bee Apis mellifera L. provides pollination services for diverse crop plants, and these services are at risk due to exposure of bees to environmental chemicals. Forager honey bees collect nectar and pollen from flowers to sustain the colony and support healthy brood development; thus pesticides in the environment could potentially be transmitted to the hive through pollen and nectar contamination. Stressors from the environment, such as pesticides, may be harmful on cellular levels and/or affect the whole organism. In order to study the synergistic effect of the thiamethoxam insecticide and the Nosema infection in Africanized honey bees, the present study will analyze the biological effects (endpoints) and cellular biomarkers that indicate responses to the interaction between insecticide and pathogen infection, by means of laboratory bioassays with larvae and adults. For this purpose, honey bees will be collect from the experimental groups and the organs (midgut and hypopharingeal glands) will be removed for morphological, ultrastructural and imunohistochemical studies. Mortality tax and alterations in the larval development (biological effects) will be noted for statistical analysis. The evaluation of the cellular biomarkers in the organs would provide the following diagnostics: I- some damages can be repaired and cellular homeostasis is restorable (compensatory response); II- cells that remain viable after intermediate level of damage (compensatory response); III- cells undergo apoptosis, macroautophagy or necrosis after a high level of damage (non-compensatory responses). The present study will add information about the side-effects of insecticide and Nosema infection on honey bee, as well as identifying possible biomarkers in cellular level that indicates sublethal damages in this important pollinator of agroecosystems. (AU)