Honeybee (Apis mellifera L.) larvae were reared in the incubator and were provisioned with an artificial diet and treated with concentrations of 9 different pesticides in two different experiments. In the first experiment, cell death in the midgut, salivary glands and ovaries of larval honeybees was detected using DNA fragmentation labeling and phosphatidylserine (PS). All applied pesticides triggered a significant increase in cell apoptosis in treated larvae over that in untreated larvae. The level of cell death in the midgut of simazine-treated larvae was highest at 77% mortality and statistically similar to the level of cell death for chlorpyrifos (65%), imidacloprid (61%), myclobutanil (69%), and glyphosate (69%) treated larvae. Larvae exposed to fluvalinate had the lowest midgut apoptotic columnar cell death (30%) of any pesticide treated larvae. Annexin V localization, indicative of apoptotic cell deletion, had an extensive distribution in the midgut, salivary glands and ovaries of pesticide-treated larvae. We have clearly demonstrated and localized cell death as an indicator for subclinical and sub-lethal effect of external influences on honey bee larval tissues.
COBISS.SI-ID: 3506280
Newly mated honey bee (Apis mellifera carnica) queens were collected from mating nuclei in queen rearing operations. Altogether, 81 queens were sampled and analysed for the presence of four viruses: acute bee paralysis virus (ABPV), black queen cell virus (BQCV), sacbrood virus (SBV) and deformed wing virus (DWV) by using reverse transcription polymerase chain reaction (RT-PCR). In 2006, 12%, 9% and 1% prevalence was found for ABPV, DWV and SBV; BQCV was not detected. Two years later, DWV, BQCV, SBV and ABPV were detected in 58%, 24 %, 11% and 10% bee queens. This is the first evidence of virus infection occurring in newly mated queens from mating nuclei in rearing apiaries.
COBISS.SI-ID: 3869800
In the experiments honey bee (Apis mellifera) larvae were exposed to one of nine pesticides and/or were challenged with the parasitic mite, Varroa destructor. Gene-expression changes in larvae were measured using quantitative PCR (qPCR) targeting transcripts for pathogens and genes involved in physiological processes, bee health, immunity, and/or xenobiotic detoxification. We discovered that Varroa-parasitized brood resulted in significantly higher transcript abundances for the antimicrobial peptides abaecin, hymenoptaecin, and defensin1. Transcript levels for Prophenoloxidase-activating enzyme (PPOact), an immune end product, were elevated in larvae treated with myclobutanil and chlorothalonil (both are fungicides)(P(0.001). Transcript levels for Hexameric storage protein (Hsp70) were significantly upregulated in imidacloprid, fluvalinate, coumaphos, myclobutanil, and amitraz treated larvae. We demonstrated definitive impacts of pesticides and Varroa parasitism on honey bee larval gene expression.
COBISS.SI-ID: 3839592
Honeybee workers (Apis mellifera carnica Polm.) were treated with imidacloprid or coumaphos. We found significant effects of treatment (pesticide) and treatment duration on hypopharyngeal glands (HPG) acinus diameter (P ( 0.05). Differences in the size of acini were evident in all long term treatments. In workers coumaphos triggered an increased level of programmed cell death, and imidacloprid induced extended necrosis. Our results suggest that both pesticides treatments have an influence on the reduced size of HPG and also on the extended expression of cell death.
COBISS.SI-ID: 3171432