Toxicity assessment of chronic exposure to common insecticides and bee medications on colony development and drones sperm parameters

Abstract

The effect of agrochemicals and beekeeping treatments on drones have not been widely investigated compared to workers or queens. In the present study, we investigated the chronic exposure of chemicals set (deltamethrin, acetamiprid, oxalic acid, fumagillin, and amitraz) on some sperm parameters and on the histomorphology of seminal vesicles. We also assessed the colony development and nosema load before and after the exposure. Thirty native Apis mellifera anatolica honeybee colonies with sister queens equalized with brood and total frame of bees were used for this experiment. Five colonies were used for each group. Deltamethrin, acetamiprid and fumagillin were given as oral chronic exposure at final concentrations of 25.10 -6 mg L −1 , 0.01 m L −1 and 50 mg L −1 respectively in syrup solution (50/50). Colonies were exposed to oxalic acid by spraying 5 mL per frame space of 3% (w/v) of oxalic acid dihydrate. Finally, the amitraz was applied based on the manufacturer's instructions. The concentrations chosen represented the field-realistic concentrations and those used by beekeepers in the region. Results showed that deltamethrin reduced brood production. In the same group, we found a high increase in nosema load. All treatments decreased sperm count except for fumagillin but this compound increased sperm mortality and increased the percentage of sperm with defected acrosome integrity. The amitraz exhibited a high sperm mortality and high percentage of sperm with defected membrane integrity function. The sperm parameters such as the count, the motility, the acrosome integrity, the membrane function of sperm, and the histomorphology of seminal vesicles of drones exposed to oxalic acid were the most affected. Bee medications commonly used such as oxalic acid and fumagillin should be more investigated and should be considered by beekeepers and particularly queen breeders.

The Role of Nosema ceranae (Microsporidia: Nosematidae) in Honey Bee Colony Losses and Current Insights on Treatment

“…Treatment with oxalic acid decreased the number of spores in an 8-day laboratory experiment, and the prevalence of infection was reduced when it was administered to free-flying colonies twice in autumn [ 125 ]. However, sperm parameters such as the count the motility, the acrosome integrity, the membrane function of sperm, and the histomorphology of seminal vesicles are affected when drones are exposed to this product [ 126 ].…”

Effects of Plant Protection Products on Biochemical Markers in Honey Bees

“…All of the mentioned changes at the molecular level may cause dysregulation in the functioning of the bee's organism, which may manifest itself in behavioral changes, disease resistance, development, production of brood, and finally the weakening of the colony condition and performance. Although most of the studies involved honey bee workers, PPPs are not indifferent to queens and drones [10,18,19,25,29,32,33,47,48,55]. PPPs altered the activity of detoxification, antioxidant, and immune-related enzymes and reduced sperm concentration and viability, which altogether can result in reduced quality and quantity of the bee brood, thereby weakening the bee colony.…”

“…It results in excitation, exhaustion, and subsequent paralysis and death of insects and mites [58]. Studies of the biochemical effect in honey bees involved deltamethrin, lambda-cyhalothrin, and beta-cyhalothrin [30,44,48,59].…”

“…In turn, they result in uncontrolled movement, paralysis, and eventually death [60]. Studies of the biochemical effect in honey bees involved carbaryl and oxamyl [28,30,48].…”

Screening of Dietary Ingredients against the Honey Bee Parasite Nosema ceranae

“…Fumagillin residues persist in hives and its degradation products pose a potential risk for human health [18,19]. For instance, fumagillin toxicity was assessed in honey bees, causing a reduction in their lifespans [20], an alteration of structural and metabolic proteins in midgut [21], a reduction in sperm quality [22] and health [13]. Moreover, its efficacy depends on several factors such as seasonality and plantations [23].…”