Juvenile hormone pathway in honey bee larvae: A source of possible signal molecules for the reproductive behavior of Varroa destructor

Juvenile hormones (JHs) play a crucial role in the development of honey bee (Apis mellifera) worker larvae. Juvenile hormone analogs (JHAs), insecticides widely used in pest control, have been reported to affect the health and survival of honey bee worker larvae. However, the molecular mechanisms of JHAs in the honey bee remain unclear. In this study, we treated honey bee worker larvae with pyriproxyfen, fenoxycarb, and methoprene, three different JHAs. We monitored the changes in the transcription of genes encoding major JH response enzymes (CYP15A1, CYP6AS5, JHAMT, and CHT1) using RT-qPCR and analyzed the transcriptome changes in worker larvae under JHA stress using RNA-seq. We found that the enrichment pathways differed among the treatment groups, but the classification of each pathway was generally the same, and fenoxycarb affected more genes and more pathways than did the other two JHAs. Notably, treatment with different JHAs in the honey bee changed the JH titers in the insect to various extents. These results represent the first assessment of the effects of three different JHAs on honey bee larvae and provide a new perspective and molecular basis for the research of JH regulation and JHA toxicity in the honey bee.

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Identification and Treatment of European Foulbrood in Honey Bee Colonies

EDIS ◽

10.32473/edis-in1272-2019 ◽

2020 ◽

Vol 2020 (1) ◽

pp. 7

Author(s):

Catherine M. Mueller ◽

Cameron Jack ◽

Ashley N. Mortensen ◽

Jamie D. Ellis

Keyword(s):

Honey Bee ◽

Bacterial Disease ◽

American Foulbrood ◽

Fact Sheet ◽

European Foulbrood ◽

Bee Colonies ◽

Honey Bee Larvae

European foulbrood is a bacterial disease that affects Western honey bee larvae. It is a concern to beekeepers everywhere, though it is less serious than American foulbrood because it does not form spores, which means that it can be treated. This 7-page fact sheet written by Catherine M. Mueller, Cameron J. Jack, Ashley N. Mortensen, and Jamie Ellis and published by the UF/IFAS Entomology and Nematology Department describes the disease and explains how to identify it to help beekeepers manage their colonies effectively and prevent the spread of both American and European foulbrood.https://edis.ifas.ufl.edu/in1272

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The role of hormones

10.1093/oso/9780198797500.003.0004 ◽

2018 ◽

Author(s):

H. Frederik Nijhout ◽

Emily Laub

Keyword(s):

Phenotypic Plasticity ◽

Social Behavior ◽

Parental Care ◽

Juvenile Hormone ◽

Reproductive Behavior ◽

Hormonal Control ◽

Plastic Trait

Many behaviors of insects are stimulated, modified, or modulated by hormones. The principal hormones involved are the same as the ones that control moulting, metamorphosis, and other aspects of development, principally ecdysone and juvenile hormone. In addition, a small handful of neurosecretory hormones are involved in the control of specific behaviors. Because behavior is a plastic trait, this chapter begins by outlining the biology and hormonal control of phenotypic plasticity in insects, and how the hormonal control of behavior fits in with other aspects of the control of phenotypic plasticity. The rest of the chapter is organized around the diversity of behaviors that are known to be controlled by or affected by hormones. These include eclosion and moulting behavior, the synthesis and release of pheromones, migration, parental care, dominance, reproductive behavior, and social behavior.

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Exploring Two Honey Bee Traits for Improving Resistance Against Varroa destructor: Development and Genetic Evaluation

Insects ◽

10.3390/insects12030216 ◽

2021 ◽

Vol 12 (3) ◽

pp. 216

Author(s):

Matthieu Guichard ◽

Benoît Droz ◽

Evert W. Brascamp ◽

Adrien von Virag ◽

Markus Neuditschko ◽

...

Keyword(s):

Apis Mellifera ◽

Honey Bee ◽

Honey Bees ◽

Varroa Destructor ◽

Field Trial ◽

Genetic Evaluation ◽

Phenotypic Correlation ◽

Apis Mellifera Mellifera ◽

Novel Traits ◽

Resistance Traits

For the development of novel selection traits in honey bees, applicability under field conditions is crucial. We thus evaluated two novel traits intended to provide resistance against the ectoparasitic mite Varroa destructor and to allow for their straightforward implementation in honey bee selection. These traits are new field estimates of already-described colony traits: brood recapping rate (‘Recapping’) and solidness (‘Solidness’). ‘Recapping’ refers to a specific worker characteristic wherein they reseal a capped and partly opened cell containing a pupa, whilst ‘Solidness’ assesses the percentage of capped brood in a predefined area. According to the literature and beekeepers’ experiences, a higher recapping rate and higher solidness could be related to resistance to V. destructor. During a four-year field trial in Switzerland, the two resistance traits were assessed in a total of 121 colonies of Apis mellifera mellifera. We estimated the repeatability and the heritability of the two traits and determined their phenotypic correlations with commonly applied selection traits, including other putative resistance traits. Both traits showed low repeatability between different measurements within each year. ‘Recapping’ had a low heritability (h2 = 0.04 to 0.05, depending on the selected model) and a negative phenotypic correlation to non-removal of pin-killed brood (r = −0.23). The heritability of ‘Solidness’ was moderate (h2 = 0.24 to 0.25) and did not significantly correlate with resistance traits. The two traits did not show an association with V. destructor infestation levels. Further research is needed to confirm the results, as only a small number of colonies was evaluated.

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