Differential Production of Nitric Oxide and Hydrogen Peroxide among Drosophila melanogaster, Apis mellifera, and Mamestra brassicae Immune-Activated Hemocytes after Exposure to Imidacloprid and Amitraz

Abstract

Invertebrates have a diverse immune system that responds differently to stressors such as pesticides and pathogens, which leads to different degrees of susceptibility. Honeybees are facing a phenomenon called colony collapse disorder which is attributed to several factors including pesticides and pathogens. We applied an in vitro approach to assess the response of immune-activated hemocytes from Apis mellifera, Drosophila melanogaster and Mamestra brassicae after exposure to imidacloprid and amitraz. Hemocytes were exposed to the pesticides in single and co-exposures using zymosan A for immune activation. We measured the effect of these exposures on cell viability, nitric oxide (NO) production from 15 to 120 min and on extracellular hydrogen peroxide (H2O2) production after 3 h to assess potential alterations in the oxidative response. Our results indicate that NO and H2O2 production is more altered in honeybee hemocytes compared to D. melanogaster and M. brassicae cell lines. There is also a differential production at different time points after pesticide exposure between these insect species as contrasting effects were evident with the oxidative responses in hemocytes. The results imply that imidacloprid and amitraz act differently on the immune response among insect orders and may render honeybee colonies more susceptible to infection and pests.

Effect of fungicidal contamination on survival, morphology, and cellular immunity of Apis mellifera (Hymenoptera: Apidae)

“…At the cellular level, hemocytes (predominantly plasmatocytes and granulocytes) play an important role in immunity as they are involved in defense responses like phagocytosis, encapsulation, and nodulation, and show variations in their number in response to a foreign agent ( Kwon et al, 2014 ; Negri et al, 2014 ; Barakat et al, 2016 ). The adverse effects of insecticides on the hemocytes of honey bees have been reported ( Perveen and Ahmad, 2017 ; Sukkar et al, 2023 ) but similar studies for fungicides are lacking ( Inoue et al, 2022 ). Until now no information has been reported regarding the adverse effects of residual forms of captan and difenoconazole on honey bee broods.…”