Transcriptome Analysis of Newly Emerged Honeybees Exposure to Sublethal Carbendazim During Larval Stage

Abstract

There are increasing concerns regarding the impact of agrochemical pesticides on non-target organisms. Pesticides could cause honeybee abnormal development in response to neurotoxins such as neonicotinoid. However, knowledge of carbendazim, a widespread fungicide in beekeeping practice, influencing on honeybee (Apis mellifera L.) brain development is lacking. Large-scale transcriptome approaches were applied to determine the changes in global gene expression in the brains of newly emerged honeybees after carbendazim exposure during the larval stage. To further understand the effects of carbendazim on the brain development of honeybees, the functions of differentially expressed genes were compared between the treatment and control groups. We found that neuroregulatory genes were down-regulated after carbendazim exposure, which suggest the neurotoxic effects of this fungicide on honeybee nervous system. Carbendazim exposure also altered the expression of genes implicated in metabolism, transport, sensor, and hormone. Notably, larvae in the carbendazim-treated group observed longer time to shift into the dormant pupal state than the control group. Moreover, a low juvenile hormone and high ecdysone titers were found in the treatment group compared to control group. The data is the first report of neurotoxic effects on honeybee caused by carbendazim, and the sublethal carbendazim may disturb honeybee development and is a potential chemical threating the honeybee colonies.

Flupyradifurone reduces nectar consumption and foraging but does not alter honey bee recruitment dancing

“…The number of differentially expressed genes (116 DEGs) altered by FPF at a field-realistic level, seems to broadly correlate with its toxicity: thiamethoxam (609 DEGs), imidacloprid (578 DEGs) and carbendazim (247 DEGs) are all more toxic per dose (Lewis et al, 2016). Within these DEGs, there are broad categories of affected genes, including those relevant to defense, immunity, odor recognition, chemical communication, learning, memory, and detoxification (Shi et al, 2017;Wang et al, 2018;Wu et al, 2017a).…”

“…Much remains to be learned about how pesticide-induced changes in gene expression harm bees. However, growing data on the honey bee transcriptome profile after exposure to pesticide could aid in understanding the effects of pesticides on honey bee health (Lewis et al, 2016;Shi et al, 2017;Wang et al, 2018;Wu et al, 2017a). These studies find interesting trends in differentially expressed genes (DEGs) that are likely involved in multiple functions related to behavior (Shi et al, 2017;Wang et al, 2018;Wu et al, 2017b).…”

“…However, growing data on the honey bee transcriptome profile after exposure to pesticide could aid in understanding the effects of pesticides on honey bee health (Lewis et al, 2016;Shi et al, 2017;Wang et al, 2018;Wu et al, 2017a). These studies find interesting trends in differentially expressed genes (DEGs) that are likely involved in multiple functions related to behavior (Shi et al, 2017;Wang et al, 2018;Wu et al, 2017b). For example, sublethal exposure to imidacloprid and thiamethoxam down-regulated odorant-binding proteins (OBPs) and chemosensory proteins (CSPs), potentially reduce honey bee chemosensory abilities (Shi et al, 2017;Wu et al, 2017a).…”

“…For example, sublethal exposure to imidacloprid and thiamethoxam down-regulated odorant-binding proteins (OBPs) and chemosensory proteins (CSPs), potentially reduce honey bee chemosensory abilities (Shi et al, 2017;Wu et al, 2017a). Prior studies also found evidence of upregulated detoxification via cytochrome P450s in bees exposed to carbendazim or thiamethoxam (Shi et al, 2017;Wang et al, 2018). Researchers found that imidacloprid down-regulated muscle-related genes and this may be one source of honey bee climbing impairment (Wu et al, 2017a).…”

Neonicotinoid insecticides hinder the pupation and metamorphosis into adults in a crabronid wasp

“…An increase in vitellogenin is likely to be associated with a decrease in juvenile hormone levels 53,54 . At this point, the effects of neonicotinoids could be potentiated by benzimidazoles, which are known to alter the levels of other key regulators of insect metamorphosis, Krüppel homolog 1 55 and ecdysone 56 or steroid hormone biosynthesis in general 57 . Benzimidazoles also alter the action of microtubules, which are necessary for, e.g., tracheole migration and evagination 58 and wing disc evagination 59 .…”