- Oct 21, 2013View Source
Hi bee monitoring group,
I want to share with you my new paper presenting a way of evaluating the importance of pesticide residues in trapped pollen from honey bees. I have been reading papers from others presenting pollen residues of many different pesticides as parts per billion, with no context about toxicity, so when the time came to present my own data about pesticides in pollen, I created this hazard quotient – residue in parts per billion divided by the LD50 for honey bees. LD50 is short for the dose lethal to 50% of the bees – a standard way of measuring acute toxicity of pesticides in the laboratory.
In the paper, I relate this quotient to how much pollen is consumed per day by nurse bees - they are the ones eating pollen directly in a honey bee hive – so that a hazard quotient for pollen can be related directly to a percentage of the LD50. And, in a note at the end, I relate a similar hazard quotient for nectar to a percentage of the LD50 for nectar foraging honey bees – the stage that consumes the most nectar per day.
I have attached the PDF of the paper, and here is the link to it at PLoS ONE – an open access journal, so anyone can read and download the paper:
Read the open-access, full-text article here:
This is a honey bee focused paper, but I would be interested in your thoughts about how to adapt this approach to wild bees. Others have shown that the LD50s for wild bees are different than for honey bees (both tested as adults). (Here is a link to a recent paper comparing toxicity to honey bees with toxicity to Osmia cornifrons: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0072587) However, I think I will still be using mostly honey bee LD50s because that’s what we have for most pesticides.
But beyond that, what wild bees consume is so much different than what honey bees consume. In honey bees, the pollen is mostly consumed by adult workers in their role as nurse bees. They produce the jelly eaten by larvae, and in comments on my paper, Randy Oliver told me that pesticide residues are greatly reduced in the transformation from pollen to jelly by the nurse bees. But in wild bees, the larvae are eating the pollen directly, mixed with some nectar. So, for effects of pollen, what we should really have is an LD50 for larvae feeding directly on the pollen. Does that data even exist for any wild bees?
I’d appreciate your thoughts.
Connecticut Agricultural Experiment Stationi