Study:  Comparative toxicity of pesticides and environmental contaminants in bees: Are honey bees a useful proxy for wild bee species?

Heard,M.S., et al., Comparativetoxicity of pesticides and environmental contaminants in bees: Are honey bees a usefulproxy for wild bee species?, Sci Total Environ (2016)

Background:

  • Threats to wild and managed insect pollinators in Europe are cause for both ecological and socio-economic concern.
  • Multiple anthropogenic pressures may be exacerbating pollinator declines. One key pressure is exposure to chemicals including pesticides and other contaminants.
  • Historically the honey bee (Apis mellifera spp.) has been used as an ‘indicator’species for ‘standard’ ecotoxicological testing but it has been suggested that it is not always a good proxy for other types of eusocial and sol itary bees because of species differences in autecology and sensitivity to various stressors.
  • The researchers developed a common toxicity test system to conduct acute and chronic exposures of up to 240 h of similar doses of seven chemicals, targeting different metaboli cp athways, on three bee species (Apis mellifera spp., Bombus terrestris and Osmia bicornis).
  • The researchers compared the relative sensitivity between species in terms of potency between the chemicals and the influence of exposure time on toxicity.
  • The researchers state that while there were significant interspecific differences that varied through time, overall the magnitude of these differences (in terms of treatment effect ratios) was generally comparable (b2 fold) although there were some large divergences from this pattern.
  • They state that the results suggest that A.mellifera spp. could be used as a proxy for other bee species provided a reasonable assessment factor is used to cover interspecific variation.
  • The researchers state that their results show significant and large time dependency of toxicity across all three tested species that greatly exceeds species differences (N25 fold within test). These are rarely considered in standard regulatory testing but may have severe environmental consequences, especially when coupled with the likelihood of differential species exposures in the wild. These insights indicate that further work is required to understand how differences in toxicokinetics vary between species and mixtures of chemicals

(PDF Download Available from: https://www.researchgate.net/publication/310050491_Comparative_toxicity_of_pesticides_and
_environmental_contaminants_in_bees_Are_
honey_bees_a_useful_proxy_for_wild_bee_species - copy and paste the link into your browser).

My Comment

  • Testing on honey bees is potentially very valuable, because they can be managed easily within their colonies, and have a number of by-products that can be collected simply for testing - such as honey, wax, pollen, propolis. 
  • In addition, a colony is supposed to thrive for several years.  This means that it should be possible to conduct chronic toxicity tests on honey bees and the colony, and in addition, measure concentrations of pesticides in honey bee products over time. 
  • Colonies of wild bees may be shorter lived, and with far less by-product. Potentially, the effects of chemicals could arguably be more severe.


I genuinely dislike that we should be in a position  of testing poisons on bees, knowing we are likely to kill them.  Within the current methods of farming, and need for testing poisons, testing is demanded, but I really wish some other way would be found.  Research evidence calls in to question the value of a particular insecticide group, neonicotinoids - see: What's the point of neonicotinoids?





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