title: Extending standard testing period in honeybees to predict lifespan impacts of pesticides and heavy metals using dynamic energy budget modelling.
abstract: Concern over reported honeybee (Apis mellifera spp.) losses has highlighted chemical exposure as a risk. Current laboratory oral toxicity tests in A. mellifera spp. use short-term, maximum 96 hour, exposures which may not necessarily account for chronic and cumulative toxicity. Here, we use extended 240 hour (10 day) exposures to examine seven agrochemicals and trace environmental pollutant toxicities for adult honeybees. Data were used to parameterise a dynamic energy budget model (DEBtox) to further examine potential survival effects up to 30 day and 90 day summer and winter worker lifespans. Honeybees were most sensitive to insecticides (clothianidin > dimethoate ≫ tau-fluvalinate), then trace metals/metalloids (cadmium, arsenic), followed by the fungicide propiconazole and herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). LC50s calculated from DEBtox parameters indicated a 27 fold change comparing exposure from 48 to 720 hours (summer worker lifespan) for cadmium, as the most time-dependent chemical as driven by slow toxicokinetics. Clothianidin and dimethoate exhibited more rapid toxicokinetics with 48 to 720 hour LC50s changes of <4 fold. As effects from long-term exposure may exceed those measured in short-term tests, future regulatory tests should extend to 96 hours as standard, with extension to 240 hour exposures further improving realism.
authors.affiliation: Centre for Ecology &Hydrology, MacLean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK.
authors.forename: H
authors.initials: H
authors.lastname: Hesketh
authors.affiliation: Centre for Ecology &Hydrology, MacLean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK.
authors.forename: E
authors.initials: E
authors.lastname: Lahive
authors.affiliation: Centre for Ecology &Hydrology, MacLean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK.
authors.forename: A A
authors.initials: AA
authors.lastname: Horton
authors.affiliation: Centre for Ecology &Hydrology, MacLean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK.
authors.forename: A G
authors.initials: AG
authors.lastname: Robinson
authors.affiliation: Centre for Ecology &Hydrology, MacLean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK.
authors.forename: C
authors.initials: C
authors.lastname: Svendsen
authors.affiliation: European Food Safety Authority, 1a, Via Carlo Magno, 1A, 43126 Parma PR, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Rortais
authors.affiliation: European Food Safety Authority, 1a, Via Carlo Magno, 1A, 43126 Parma PR, Italy.
authors.forename: J-L
authors.initials: JL
authors.lastname: Dorne
authors.affiliation: Centre for Ecology &Hydrology, MacLean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK.
authors.forename: J
authors.initials: J
authors.lastname: Baas
authors.affiliation: Centre for Ecology &Hydrology, MacLean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Spurgeon
authors.affiliation: Centre for Ecology &Hydrology, MacLean Building, Benson Lane, Wallingford, Oxfordshire, OX10 8BB, UK.
authors.forename: M S
authors.initials: MS
authors.lastname: Heard