Detrimental effects of amitraz exposure in honey bees (Apis mellifera) infected with Nosema ceranae

• Published in: Parasitology research (1987) Vol. 123; no. 5; p. 204
• Main Authors: Zufriategui, Camila, Porrini, Martín Pablo, Eguaras, Martín Javier, Garrido, Paula Melisa
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-05-2024; Springer Nature B.V
• Subjects: Acaricides; Animals; Apis mellifera; Bees; Bees - drug effects; Bees - microbiology; Bees - parasitology; Biomedical and Life Sciences; Biomedicine; Chronic exposure; Food intake; Immunology; Medical Microbiology; Microbiology; Mortality; Nosema - drug effects; Nosema - physiology; Nosema ceranae; Parasites; Toluidines; Xenobiotics; Acaricide; Sublethal; Microsporidia; Stressors; Nosemosis; Chronic exposure
• ISSN: 0932-0113; 1432-1955
• DOI: 10.1007/s00436-024-08225-x

In recent years, there has been growing concern on the potential weakening of honey bees and their increased susceptibility to pathogens due to chronic exposure to xenobiotics. The present work aimed to study the effects on bees undergoing an infection by
Nosema ceranae
and being exposed to a frequently used in-hive acaricide, amitraz. To achieve this, newly emerged bees were individually infected with
N. ceranae
spores and/or received a sublethal concentration of amitraz in their diets under laboratory conditions. Mortality, food intake, total volume excrement, body appearance, and parasite development were registered. Bees exposed to both stressors jointly had higher mortality rates compared to bees exposed separately, with no difference in the parasite development. An increase in sugar syrup consumption was observed for all treated bees while infected bees fed with amitraz also showed a diminishment in pollen intake. These results coupled with an increase in the total number of excretion events, alterations in behavior and body surface on individuals that received amitraz could evidence the detrimental action of this molecule. To corroborate these findings under semi-field conditions, worker bees were artificially infected, marked, and released into colonies. Then, they were exposed to a commercial amitraz-based product by contact. The recovered bees showed no differences in the parasite development due to amitraz exposure. This study provides evidence to which extent a honey bee infected with
N. ceranae
could potentially be weakened by chronic exposure to amitraz treatment.