Synergistic effects of acaricides used to control the ectoparasitic miteVarroa destructoron the reproductive health of honey bee (Apis mellifera) queens

Abstract In the honey bee, Apis mellifera, colonies are composed of one queen, thousands of female workers, and a few thousand seasonal males (drones) that are reared only during the reproductive season when colony resources are plentiful. Despite their transient presence in the hive, drones have the important function of mating with virgin queens, transferring their colony’s genes to their mates for the production of fertilized, worker-destined eggs. Therefore, factors affecting drone health and reproductive competency may directly affect queen fitness and longevity, having great implications at the colony level. Several environmental and in-hive conditions can affect the quality and viability of drones in general and their sperm in particular. Here we review the extant studies that describe how environmental factors including nutrition, temperature, season, and age may influence drone reproductive health. We also review studies that describe other factors, such as pesticide exposure during and after development, that may also influence drone reproductive quality. Given that sperm development in drones is completed during pupation prior to adult emergence, particular attention needs to be paid to these factors during drone development, not just during adulthood. The present review showcases a growing body of evidence indicating that drones are very sensitive to environmental fluctuations and that these factors cause drones to underperform, potentially compromising the reproductive health of their queen mates, as well as the overall fitness of their colony.

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Acute Thiamethoxam exposure in Apis mellifera : Absence of both stress-induced changes in mRNA splicing and synergistic effects of common fungicide and herbicide

10.1101/641407 ◽

2019 ◽

Cited By ~ 3

Author(s):

Pâmela Decio ◽

Pinar Ustaoglu ◽

Thaisa C. Roat ◽

Osmar Malaspina ◽

Jean-Marc Devaud ◽

...

Keyword(s):

Apis Mellifera ◽

Honey Bee ◽

Pesticide Exposure ◽

Negative Impact ◽

Synergistic Effects ◽

Spliceosomal Intron ◽

Simultaneous Exposure ◽

Complex Process ◽

Induced Changes ◽

First Time

AbstractSecuring food supply for a growing population is one of the current major challenges and heavily relies on the use of agrochemicals to maximize crop yield. Neonicotinoids are globally one of the most widely used insecticides. It is increasingly recognized, that neonicotinoids have a negative impact on non-target organisms, including important pollinators such as the European honey bee Apis mellifera. Toxicity of neonicotinoids may be enhanced through simultaneous exposure with additional pesticides, which could help explain, in part, the global decline of honey bee colonies. Here we examined whether exposure effects of the neonicotinoid Thiamethoxam are enhanced by the commonly used fungicide Carbendazim and the herbicide Glyphosate. For the first time, we also analysed alternative splicing changes upon pesticide exposure in the honey bee. In particular, we examined transcripts of three genes: i) the stress sensor gene X box binding protein-1 (Xbp1), ii) the Down Syndrome Cell Adhesion Molecule (Dscam) gene and iii) the embryonic lethal/abnormal visual system (elav) gene, both important genes for neuronal function. Our results indicate that neonicotinoid toxicity applied at sub-lethal doses is not enhanced by Carbendazim nor Glyphosate. Likewise, toxicity of these compounds did not impact on the complex process of spliceosomal-directed joining of exons and non-spliceosomal intron excision in the analysed mRNAs.

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