Another Bee Study Finds CCD is Likely Due to Combination of Factors Including Pesticides

Posted on August 10, 2013  Comments (2)

Abstract of open access science paper funded by the United States Department of Agriculture (USDA) Crop Pollination Exposes Honey Bees to Pesticides Which Alters Their Susceptibility to the Gut Pathogen Nosema ceranae:

Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee colonies. Such findings are of great concern given the large numbers and high levels of pesticides found in honey bee colonies. Thus it is crucial to determine how field-relevant combinations and loads of pesticides affect bee health.

We collected pollen from bee hives in seven major crops to determine 1) what types of pesticides bees are exposed to when rented for pollination of various crops and 2) how field-relevant pesticide blends affect bees’ susceptibility to the gut parasite Nosema ceranae. Our samples represent pollen collected by foragers for use by the colony, and do not necessarily indicate foragers’ roles as pollinators. In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling.

Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability of Nosema infection in bees that consumed pollen with a higher fungicide load.

Our results highlight a need for research on sub-lethal effects of fungicides and other chemicals that bees placed in an agricultural setting are exposed to.

The attempts to discover the main causes of bee colony deaths and find solutions continues to prove difficult years after the problems became major. The complex interaction of many variables makes it difficult. And special interest groups pushing pesticides and the like, which have seemed to be major contributors to the problem for years, make it even more difficult (by preventing restrictions on potentially damaging pesticide use).

The challenges in determining what is killing bees are similar to the challenges of discovering what practices are damaging human health. The success of studying complex biological interactions (to discover threats to human health) is extremely limited. I am concerned we are far too caviler about using large numbers of interventions (drugs, pesticides, massive antibiotics use in factory farms, pollution…).

Related: Europe Bans Certain Pesticides, USA Just Keeps Looking, Bees Keep DyingGermany Bans Chemicals Linked to Bee Deaths (2008)Virus Found to be One Likely Factor in Bee Colony Colapse Disorder (2007)Study of the Colony Collapse Disorder Continues as Bee Colonies Continue to Disappear

2 Responses to “Another Bee Study Finds CCD is Likely Due to Combination of Factors Including Pesticides”

  1. Vinnie
    August 15th, 2013 @ 10:20 am

    We are simply overusing stuff these days. Whenever someone gets a headache they reach for a pill. Anything regarding health can be solved by a pill. The same goes with the environment. Instead of finding some other way of managing parasites, we use outrageous quantities of chemicals which in the end will harm not only the other beings that are vital for the plants well-being but us humans as well.
    My though is that we must change the way we deal with things or else we’ll find ourselves with a larger problem on our doorstep.

  2. Anonymous
    August 20th, 2013 @ 6:09 am

    I agree with Vinnie’s comment. There is a preoccupation with trying to cure any “ill” (whether it be a medical problem or something like pests in farming) through the use of a drug or chemical. Sometimes (some would say in many instances) these create problems far greater than the initial one. So, we use pesticides to reduce pest numbers and increase yields to give us cheaper foods whilst at the same time wiping out bee populations.. which leads eventually to less pollination and lower yields, leading to limited food and higher food prices. Crazy!

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